From ALMA: “Researchers at ALMA study the effects of working at high altitude”

ESO/NRAO/NAOJ ALMA Array in Chile in the Atacama at Chajnantor plateau, at 5,000 metres
ALMA

17 August, 2017

Nicolás Lira
Education and Public Outreach Coordinator
Joint ALMA Observatory, Santiago – Chile
Phone: +56 2 2467 6519
Cell phone: +56 9 9445 7726
nicolas.lira@alma.cl

An international team of doctors and researchers conducted a study at the Atacama Large Millimeter/submillimeter Array (ALMA) to identify the consequences of working at high altitude where the body can experience oxygen deficiency, a medical condition known as hypoxia. The extreme altitude of the observatory — 2,900 meters at the Operations Support Facility (OSF) and the Array Operations Site (AOS) at 5,000 meters — makes it a natural laboratory for this type of research, which is extremely useful to both ALMA and other operations at high altitudes. The first results of these studies are being made available to the scientific community (see posters) and will soon be published.

Canadian, Swiss, and Chilean experts met at ALMA in April 2016 to examine workers who volunteered for the study, separating those who suffer from chronic illnesses such as hypertension or obesity from healthy workers in order to compare and understand the effects of hypoxia. Over the course of six weeks, doctors examined their cognitive skills, sleep quality, breathing patterns, blood flow to the brain, and hemodynamic changes between the heart and lungs.

For Dr. Marc Poulin from the University of Calgary, Canada, who forms part of this study, “The working conditions at ALMA are ideal for our research. It has high quality infrastructure and is a true natural laboratory due to its high altitude.”

An international team of doctors and researchers conducted a study at ALMA to identify the consequences of working at high altitude where the body can experience oxygen deficiency, a medical condition known as hypoxia. The extreme altitude of the observatory — 2,900 meters at the OSF and the AOS at 5,000 meters — makes it a natural laboratory for this type of research, which is extremely useful to both ALMA and other operations at high altitudes. Credit: Iván López – ALMA (NRAO/NAOJ/ESO)

Most of the workers at the observatory live in cities located at low altitudes, and work 8×6 shifts (8 days of work followed by 6 days off) at the ALMA OSF. The camp where the workers sleep is located here, as well as the laboratories, workshops, offices and antenna control room. Some workers have to ascend to the ALMA AOS at 5,000 meters, where they work with the antennas and correlator that synchronizes their signals. It is at this higher altitude that some staff experience intermittent hypoxia.

The purpose of this study is to understand the long-term effects on workers’ performance, health, and safety from ongoing or intermittent exposure to hypoxia. This study is meant to optimize treatments that would help workers operate at altitude. It also may lead to new treatments from the lessons learned through this study in development.

“We are very happy about this study, as it gives us an objective database of the effects of hypoxia in workers and helps adapt the risk prevention program to real conditions, in order to improve the quality of life of all staff,” says Iván López, ALMA Risk Prevention, Health, Environment and Safety Manager.

An international team of doctors and researchers conducted a study at ALMA to identify the consequences of working at high altitude where the body can experience oxygen deficiency, a medical condition known as hypoxia. The extreme altitude of the observatory — 2,900 meters at the OSF and the AOS at 5,000 meters — makes it a natural laboratory for this type of research, which is extremely useful to both ALMA and other operations at high altitudes. Credit: Iván López – ALMA (NRAO/NAOJ/ESO)

Early results from these studies suggest that intermittent and/or regular exposure to high altitudes may have a negative effect on psychomotor alertness, which is especially evident in those who work on tasks that require a high level of concentration, such as those found in mining and astronomical observatories. It also has bearing on athletes performing at high altitude.

These studies also indicate that there is an alteration in workers’ sleep quality, although acclimatization would reduce these effects after a few days of exposure. Cognitive abilities would also be affected at extreme altitude exposure (5,050 meters above sea level), especially cognitive abilities and, to a much lesser extent, executive capacity. These effects would also be partially reduced as workers are acclimatized after a few days.

Among the measures taken by ALMA to reduce the effects of hypoxia are the mandatory use of portable medical oxygen for all workers performing tasks over an altitude of 3000 meters, permanent oxygenation of the technical building located at an altitude of 5000 meters, and constant on-site monitoring by the observatory’s medical team. In addition, new strategies are being developed that include a special diet and exercise program.

See the full article here .

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The Atacama Large Millimeter/submillimeter Array (ALMA), an international astronomy facility, is a partnership of Europe, North America and East Asia in cooperation with the Republic of Chile. ALMA is funded in Europe by the European Organization for Astronomical Research in the Southern Hemisphere (ESO), in North America by the U.S. National Science Foundation (NSF) in cooperation with the National Research Council of Canada (NRC) and the National Science Council of Taiwan (NSC) and in East Asia by the National Institutes of Natural Sciences (NINS) of Japan in cooperation with the Academia Sinica (AS) in Taiwan.

ALMA construction and operations are led on behalf of Europe by ESO, on behalf of North America by the National Radio Astronomy Observatory (NRAO), which is managed by Associated Universities, Inc. (AUI) and on behalf of East Asia by the National Astronomical Observatory of Japan (NAOJ). The Joint ALMA Observatory (JAO) provides the unified leadership and management of the construction, commissioning and operation of ALMA.

From CfA: “Magnetic Fields in Massive, Star Formation Cores”

Center For Astrophysics

A far-infrared image of the long filament of star formation activity known as DR21, seen here in emission by the Herschel Space Telescope. A study of the magnetic field along the filament and around six star-forming cores within it finds that magnetic effects are primarily important during the early stages of star formation. ESA/Herschel

ESA/Herschel spacecraft

Studies of molecular clouds have revealed that star formation usually occurs in a two step process. First, supersonic flows compress the clouds into dense filaments light-years long, after which gravity collapses the densest material in the filament into cores. In this scenario, massive cores (each more than about twenty solar–masses) preferentially form at intersections where filaments cross, producing sites of clustered star formation. The process sounds reasonable and is expected to be efficient, but the observed rate of star formation in dense gas is only a few percent of the rate expected if the material really were freely collapsing. To solve the problem, astronomers have proposed that magnetic fields support the cores against the collapse induced by self-gravity.

Magnetic fields are difficult to measure and difficult to interpret. CfA astronomers Tao-Chung Ching, Qizhou Zhang, and Josep Girat led a team that used the Submillimeter Array to study six dense cores in a nearby star formation region in Cygnus.

CfA Submillimeter Array Mauna Kea, Hawaii, USA

They measured the field strengths from the polarization of the millimeter radiation; elongated dust grains are known to be aligned by magnetic fields and to scatter light with a preferred polarization direction. The scientists then correlated the field direction in these cores with the field direction along the filament out of which the cores developed.

The astronomers find that the magnetic field along the filament is well-ordered and parallel to the structure, but at the cores themselves the field direction is much more complex, sometimes parallel and sometimes perpendicular. They conclude that during the formation of the cores the magnetic fields, at least at small scales, become unimportant compared to turbulence and infall. Although the field may play an important role as the filament initially collapses, once the dense cores develop the local kinematics from infall and gravitational effects become more important.

Reference(s):

Magnetic Fields in the Massive Dense Cores of the DR21 Filament: Weakly Magnetized Cores in a Strongly Magnetized Filament,Tao-Chung Ching, Shih-Ping Lai1, Qizhou Zhang, Josep M. Girart, Keping Qiu, and Hauyu B. Liu, ApJ 838, 121, 2017.

See the full article here .

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The Center for Astrophysics combines the resources and research facilities of the Harvard College Observatory and the Smithsonian Astrophysical Observatory under a single director to pursue studies of those basic physical processes that determine the nature and evolution of the universe. The Smithsonian Astrophysical Observatory (SAO) is a bureau of the Smithsonian Institution, founded in 1890. The Harvard College Observatory (HCO), founded in 1839, is a research institution of the Faculty of Arts and Sciences, Harvard University, and provides facilities and substantial other support for teaching activities of the Department of Astronomy.

From ALMA: “Running Out of Gas: Gas Loss Puts Breaks on Stellar Baby Boom”

ESO/NRAO/NAOJ ALMA Array in Chile in the Atacama at Chajnantor plateau, at 5,000 metres
ALMA

2 August, 2017

Nicolás Lira
Education and Public Outreach Coordinator
Joint ALMA Observatory, Santiago – Chile
Phone: +56 2 2467 6519
Cell phone: +56 9 9445 7726
nicolas.lira@alma.cl

Masaaki Hiramatsu
Education and Public Outreach Officer, NAOJ Chile
Observatory
, Tokyo – Japan
Phone: +81 422 34 3630
hiramatsu.masaaki@nao.ac.jp

Charles E. Blue
Public Information Officer
National Radio Astronomy Observatory Charlottesville, Virginia – USA
Phone: +1 434 296 0314
Cell phone: +1 202 236 6324
cblue@nrao.edu

Richard Hook
Public Information Officer, ESO
Garching bei München, Germany
Phone: +49 89 3200 6655
Cell phone: +49 151 1537 3591
rhook@eso.org

No image caption or credit

Astronomers observed a galaxy cluster 9.4 billion light-years away using the ALMA radio telescope array and found evidence that hot gas strips away the cold gas in the member galaxies. Since cold gas is the material for forming new stars, removing the cold gas inhibits star formation. This result is key to understanding the declining birthrate of stars throughout the history of the Universe and the evolutionary process of galaxy clusters.

Understanding the history of star formation in the Universe is a central theme in modern astronomy. Various observations have shown that the star formation activity has varied through the 13.8 billion-year history of the Universe. The stellar birth rate peaked around 10 billion years ago and has declined steadily since then. However, the cause of the declining stellar birth rate is still not well understood.

“Aiming to investigate what suppresses the star formation activity, we focused on the environment around the galaxies,” said Masao Hayashi at the National Astronomical Observatory of Japan (NAOJ).

Hayashi and his colleagues observed the galaxy cluster XMMXCS J2215.9–1738 located 9.4 billion light-years away [1] with the Atacama Large Millimeter/submillimeter Array (ALMA). Because it takes time for the light from distant objects to reach us, observing far-away galaxies shows us what the Universe looked like when the light was emitted. In this case, the light from XMMXCS J2215.9-1738 was emitted 9.4 billion years ago, which is around the time that the stellar birth rate peaked. In fact, previous observations with NAOJ’s Subaru Telescope revealed that many of the galaxies in the cluster are actively forming stars.

NAOJ/Subaru Telescope at Mauna Kea Hawaii, USA

ALMA detected radio signals emitted from carbon monoxide gas in 17 of the galaxies in the cluster. This is a record-high number for the detection of gas-rich galaxies at such a distance. Interestingly, the gas-rich galaxies detected with ALMA are located towards the outer part of the galaxy cluster, not in the center. This is the first time ever that such a location differentiation has been found in a galaxy cluster 10 billion light-years away.

Galaxy cluster XMMXCS J2215.9–1738 observed with ALMA and the Hubble Space Telescope. Gas rich galaxies detected with ALMA are shown in red and marked with circles. Most gas rich galaxies are located in the outer part, not the center, of the galaxy cluster (around the center of the image). Credit: ALMA (ESO/NAOJ/NRAO), Hayashi et al., the NASA/ESA Hubble Space Telescope

NASA/ESA Hubble Telescope

The team assumes that the gas-rich galaxies detected with ALMA are in an intermediate step in the process of becoming members of the cluster. As new member galaxies pass through the hot gas filling the cluster, cold gas in the galaxies is stripped away by the hot gas. Active star formation consumes what little gas survives in the galaxies. As the cold gas needed to make stars run out, star formation stops.

Actually, there are some galaxies with active star formation at the central part of the cluster. The team suggests that they are rather evolved, old members of the cluster consuming the last of their gas to form stars.

“Recent observational and theoretical studies show that the distribution of gas is key to understanding the evolution of galaxies,” explains Hayashi. “Our observations provide robust statistics showing that a number of gas-rich galaxies are located in the outer part of a galaxy cluster. With this result, we have opened a future path for revealing the evolutionary process of galaxies in galaxy clusters.”

Notes

[1] The measured redshift of the galaxy cluster is z=1.46. A calculation based on the latest cosmological parameters measured with Planck (H0=67.3 km/s/Mpc, Ωm=0.315, Λ=0.685: Planck 2013 Results) yields the distance of 9.4 billion light-years. Please refer to “Expressing the distance to remote objects” for the details.

Additional Information

These observation results were published as Hayashi et al. Evolutionary Phases of Gas-rich Galaxies in a Galaxy Cluster at z = 1.46 in The Astrophysical Journal Letters in May 2017.

The research team members are: Masao Hayashi (National Astronomical Observatory of Japan), Tadayuki Kodama (NAOJ/SOKENDAI/Tohoku University), Kotaro Kohno (The University of Tokyo), Yuki Yamaguchi (The University of Tokyo), Ken-ichi Tadaki (NAOJ/Max Planck Institute for Extraterrestrial Physics), Bunyo Hatsukade (The University of Tokyo), Yusei Koyama (NAOJ/SOKENDAI), Rhythm Shimakawa (NAOJ/University of California), Yoichi Tamura (The University of Tokyo/Nagoya University), and Tomoko L. Suzuki (NAOJ)

This research was supported by Grants-in-Aid from the Japan Society for the Promotion of Science and the Ministry of Education, Culture, Sports, Science and Technology, Japan (No. 26707006, 21340045, 24244015, 15H02073, 25247019).

See the full article here .

Please help promote STEM in your local schools.

Stem Education Coalition

The Atacama Large Millimeter/submillimeter Array (ALMA), an international astronomy facility, is a partnership of Europe, North America and East Asia in cooperation with the Republic of Chile. ALMA is funded in Europe by the European Organization for Astronomical Research in the Southern Hemisphere (ESO), in North America by the U.S. National Science Foundation (NSF) in cooperation with the National Research Council of Canada (NRC) and the National Science Council of Taiwan (NSC) and in East Asia by the National Institutes of Natural Sciences (NINS) of Japan in cooperation with the Academia Sinica (AS) in Taiwan.

ALMA construction and operations are led on behalf of Europe by ESO, on behalf of North America by the National Radio Astronomy Observatory (NRAO), which is managed by Associated Universities, Inc. (AUI) and on behalf of East Asia by the National Astronomical Observatory of Japan (NAOJ). The Joint ALMA Observatory (JAO) provides the unified leadership and management of the construction, commissioning and operation of ALMA.

From COSMOS: “How non-optical telescopes see the universe”

COSMOS Magazine

24 July 2017
Jake Port

The human eye can only see a tiny band of the electromagnetic spectrum. That tiny band is enough for most day-to-day things you might want to do on Earth, but stars and other celestial objects radiate energy at wavelengths from the shortest (high-energy, high-frequency gamma rays) to the longest (low-energy, low-frequency radio waves).

The electromagnetic spectrum is made up of radiation of all frequencies and wavelengths. Only a tiny range is visible to the human eye. NASA.

Beyond the visible spectrum

To see what’s happening in the distant reaches of the spectrum, astronomers use non-optical telescopes. There are several varieties, each specialised to catch radiation of particular wavelengths.

Non-optical telescopes utilise many of the techniques found in regular telescopes, but also employ a variety of techniques to convert invisible light into spectacular imagery. In all cases, a detector is used to capture the image rather than an eyepiece, with a computer then processing the data and constructing the final image.

There are also more exotic ways of looking at the universe that don’t use electromagnetic radiation at all, like neutrino telescopes and the cutting-edge gravitational wave telescopes, but they’re a separate subject of their own.

To start off, let’s go straight to the top with the highest-energy radiation, gamma rays.

Gamma ray telescopes

Gamma radiation is generally defined as radiation of wavelengths less than 10−11 m, or a hundredth of a nanometre.

Gamma-ray telescopes focus on the highest-energy phenomena in the universe, such as black holes and exploding stars. A high-energy gamma ray may contain a billion times as much energy as a photon of visible light, which can make them difficult to study.

Unlike photons of visible light, that can be redirected using mirrors and reflectors, gamma rays simply pass through most materials. This means that gamma-ray telescopes must use sophisticated techniques that track the movement of individual gamma rays to construct an image.

One technology that does this, in use in the Fermi Gamma-ray Space Telescope among other places, is called a pair production telescope.

NASA/Fermi Telescope

It uses a multi-layer sandwich of converter and detector materials. When a gamma ray enters the front of the detector it hits a converter layer, made of dense material such as lead, which causes the gamma-ray to produce an electron and a positron (known as a particle-antiparticle pair).

The electron and the positron then continue to traverse the telescope, passing through layers of detector material. These layers track the movement of each particle by recording slight bursts of electrical charge along the layer. This trail of bursts allows astronomers to reconstruct the energy and direction of the original gamma ray. Tracing back along that path points to the source of the ray out in space. This data can then be used to create an image.

The video below shows how this works in the space-based Fermi Large Area Telescope.

NASA/Fermi LAT

X-ray telescopes

X-rays are radiation with wavelengths between 10 nanometres and 0.01 nanometres. They are used every day to image broken bones and scan suitcases in airports and can also be used to image hot gases floating in space. Celestial gas clouds and remnants of the explosive deaths of large stars, known as supernovas, are the focus of X-ray telescopes.

Like gamma rays, X-rays are a high-energy form of radiation that can pass straight through most materials. To catch X-rays you need to use materials that are very dense.

X-ray telescopes often use highly reflective mirrors that are coated with dense metals such as gold, nickel or iridium. Unlike optical mirrors, which can bounce light in any direction, these mirrors can only slightly deflect the path of the X-ray. The mirror is orientated almost parallel to the direction of the incoming X-rays. The X-rays lightly graze the mirror before moving on, a little like a stone skipping on a pond. By using lots of mirrors, each changing the direction of the radiation by a small amount, enough X-rays can be collected at the detector to produce an image.

To maximise image quality the mirrors are loosely stacked, creating an internal structure resembling the layers of an onion.

Diagram showing how ‘grazing incidence’ mirrors are used in X-ray telescopes. NASA.

NASA/Chandra X-ray Telescope

ESA/XMM Newton X-ray telescope

NASA NuSTAR X-ray telescope

Ultraviolet telescopes

Ultraviolet light is radiation with wavelengths just too short to be visible to human eyes, between 400 nanometres and 0.01 nanometres. It has less energy than X-rays and gamma rays, and ultraviolet telescopes are more like optical ones.

Mirrors coated in materials that reflect UV radiation, such as silicon carbide, can be used to redirect and focus incoming light. The Hopkins Ultraviolet Telescope, which flew two short missions aboard the space shuttle in the 1990s, used a parabolic mirror coated with this material.

A schematic of the Hopkins Ultraviolet Telescope. NASA.

NASA Hopkins Ultraviolet Telescope which flew on the ISS

As redirected light reaches the focal point, a central point where all light beams converge, they are detected using a spectrogram. This specialised device can separate the UV light into individual wavelength bands in a way akin to splitting visible light into a rainbow.

Analysis of this spectrogram can indicate what the observation target is made of. This allows astronomers to analyse the composition of interstellar gas clouds, galactic centres and planets in our solar system. This can be particularly useful when looking for elements essential to carbon-based life such as oxygen and carbon.

Optical telescopes

Optical telescopes are used to view the visible spectrum: wavelengths roughly between 400 and 700 nanometres. See separate article here.

Keck Observatory, Maunakea, Hawaii, USA

ESO/VLT at Cerro Paranal, with an elevation of 2,635 metres (8,645 ft) above sea level

Gran Telescopio Canarias at the Roque de los Muchachos Observatory on the island of La Palma, in the Canaries, Spain, sited on a volcanic peak 2,267 metres (7,438 ft) above sea level

Gemini/North telescope at Maunakea, Hawaii, USA

Gemini South telescope, Cerro Tololo Inter-American Observatory (CTIO) campus near La Serena, Chile

Infrared telescopes

Sitting just below visible light on the electromagnetic spectrum is infrared light, with wavelengths between 700 nanometres and 1 millimetre.

It’s used in night vision goggles, heaters and tracking devices as found in heat-seeking missiles. Any object or material that is hotter than absolute zero will emit some amount of infrared radiation, so the infrared band is a useful window to look at the universe through.

Much infrared radiation is absorbed by water vapour in the atmosphere, so infrared telescopes are usually at high altitudes in dry places or even in space, like the Spitzer Space Telescope.

Infrared telescopes are often very similar to optical ones. Mirrors and reflectors are used to direct the infrared light to a detector at the focal point. The detector registers the incoming radiation, which a computer then converts into a digital image.

NASA/Spitzer Infrared Telescope

Radio telescopes

At the far end of the electromagnetic spectrum we find the radio waves, with frequencies less than 1000 megahertz and wavelengths of a metre and more. Radio waves penetrate the atmosphere easily, unlike higher-frequency radiation, so ground-based observatories can catch them.

Radio telescopes feature three main components that each play an important role in capturing and processing incoming radio signals.

The first is the massive antenna or ‘dish’ that faces the sky. The Parkes radio telescope in New South Wales, Australia, for instance, has a dish with a diameter of 64 metres, while the Aperture Spherical Telescope in southwest China is has a whopping 500-metre diameter.

The great size allows for the collection of long wavelengths and very quiet signals. The dish is parabolic, directing radio waves collected over a large area to be focused to a receiver sitting in front of the dish. The larger the antenna, the weaker the radio source that can be detected, allowing larger telescopes to see more distant and faint objects billions of light years away.

The receiver works with an amplifier to boost the very weak radio signal to make it strong enough for measurement. Receivers today are so sensitive that they use powerful coolers to minimise thermal noise generated by the movement of atoms in the metal of the structure.

Finally, a recorder stores the radio signal for later processing and analysis.

Radio telescopes are used to observe a wide array of subjects, including energetic pulsar and quasar systems, galaxies, nebulae, and of course to listen out for potential alien signals.

CSIRO/Parkes Observatory, located 20 kilometres north of the town of Parkes, New South Wales, Australia

GBO radio telescope, Green Bank, West Virginia, USA

See the full article here .

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From ALMA: “Heart of an Exploded Star Observed in 3-D”

ESO/NRAO/NAOJ ALMA Array in Chile in the Atacama at Chajnantor plateau, at 5,000 metres
ALMA

10 July, 2017

Nicolás Lira
Education and Public Outreach Coordinator
Joint ALMA Observatory, Santiago – Chile
Phone: +56 2 2467 6519
Cell phone: +56 9 9445 7726
nicolas.lira@alma.cl

Charles E. Blue
Public Information Officer
National Radio Astronomy Observatory Charlottesville, Virginia – USA
Phone: +1 434 296 0314
Cell phone: +1 202 236 6324
cblue@nrao.edu

Masaaki Hiramatsu
Education and Public Outreach Officer, NAOJ Chile
Observatory
, Tokyo – Japan
Phone: +81 422 34 3630
hiramatsu.masaaki@nao.ac.jp

Richard Hook
Public Information Officer, ESO
Garching bei München, Germany
Phone: +49 89 3200 6655
Cell phone: +49 151 1537 3591
rhook@eso.org

This artist’s illustration of Supernova 1987A reveals the cold, inner regions of the exploded star’s remnants (red) where tremendous amounts of dust were detected and imaged by ALMA. This inner region is contrasted with the outer shell (blue), where the energy from the supernova is colliding (green) with the envelope of gas ejected from the star prior to its powerful detonation. Credit: A. Angelich; NRAO/AUI/NSF

Deep inside the remains of an exploded star lies a twisted knot of newly minted molecules and dust forged in the cooling aftermath of a supernova first detected in 1987. Using ALMA, astronomers mapped the location of these new molecules to create a high-resolution 3-D image of this “dust factory,” providing important insights into the relationship between a young supernova remnant and its home galaxy.

Supernovas — the violent ending of the brief but brilliant lives of massive stars — are among the universe’s most cataclysmic events. Though supernovas mark the death of stars, they also trigger the birth of new elements and the formation of molecules that fill the universe.

In February of 1987, astronomers witnessed one of these events unfold inside the Large Magellanic Cloud, a tiny dwarf galaxy in the suburbs of the Milky Way approximately 163,000 light-years from Earth.

Over the next 30 years, observations of the remnant of that explosion revealed never-before-seen details about the death of stars and how atoms created in those stars — like carbon, oxygen, and nitrogen — spill out into space and combine to form new molecules and dust. These microscopic particles may eventually find their way into future generations of stars and planets.

Remnant of Supernova 1987A as seen by ALMA. Purple area indicates emission from SiO molecules. Yellow area is emission from CO molecules. The blue ring is actual Hubble data (H-alpha) that has been artificially expanded into 3-D. Credit: ALMA (ESO/NAOJ/NRAO); R. Indebetouw

NASA/ESA Hubble Telescope

Recently, astronomers used the Atacama Large Millimeter/submillimeter Array (ALMA) to probe the heart of this supernova, named SN 1987A. ALMA’s ability to see remarkably fine details allowed the researchers to produce a detailed 3-D rendering of newly formed molecules inside the supernova remnant. These results are published in the Astrophysical Journal Letters.

The researchers also discovered a variety of previously undetected molecules in the remnant. Those results will appear in the Monthly Notices of the Royal Astronomical Society.

“When this supernova exploded now more than 30 years ago, astronomers knew much less about the way these events reshape interstellar space and how the hot, glowing debris from an exploded star eventually cools and produces new molecules,” said Rémy Indebetouw, an astronomer at the University of Virginia and the National Radio Astronomy Observatory (NRAO) in Charlottesville. “Thanks to ALMA we can finally see cold ‘star dust’ as it forms, revealing important insights into the original star itself and the way supernovas create the basic building blocks of planets.”

Supernovas – Star Death to Dust Birth

Prior to ongoing investigations of SN 1987A, there was only so much astronomers could determine about these explosive cosmic events.

It was well understood that massive stars, those approximately 10 times the mass of our sun, ended their lives in spectacular fashion. When these stars run out of fuel, there is no longer enough heat and energy to fight back against the force of gravity. The outer reaches of the star, once held up by the power of fusion, then come crashing down on the core with tremendous force. The rebound of this collapse triggers an explosion that blasts material into space.

As the endpoint of massive stars, scientists have learned that supernovas have far-reaching effects on galaxies across the universe. To get a better understanding of these effects, Indebetouw helps break down the impact of these star-shattering events. “The reason some galaxies have the appearance that they do today is in large part because of the supernovas that have occurred in them,” he said. “Though less than 10 percent of stars in galaxies , the ones that explode as supernovas dominate the evolution of galaxies.”

Throughout the observable universe, supernovas are quite common, but since they appear – on average – about once every 50 years in a galaxy the size of the Milky Way, astronomers have precious few opportunities to study one from its first detonation to the point where it cools enough to form new molecules. Though SN 1987A is not technically in our home galaxy, it is still close enough for ALMA and other telescopes to study in fine detail.

Astronomers combined observations from three different observatories to produce this colorful, multiwavelength image of the intricate remains of Supernova 1987A.The red color shows newly formed dust in the center of the supernova remnant, taken at submillimeter wavelengths by the Atacama Large Millimeter/submillimeter Array (ALMA) telescope in Chile. The green and blue hues reveal where the expanding shock wave from the exploded star is colliding with a ring of material around the supernova. The green represents the glow of visible light, captured by NASA’s Hubble Space Telescope. The blue color reveals the hottest gas and is based on data from NASA’s Chandra X-ray Observatory.The ring was initially made to glow by the flash of light from the original explosion. Over subsequent years the ring material has brightened considerably as the explosion’s shock wave slams into it. Supernova 1987A resides 163,000 light-years away in the Large Magellanic Cloud, where a firestorm of star birth is taking place. Credit: NASA/ESA, ALMA (ESO/NAOJ/NRAO)

NASA/Chandra Telescope

Capturing 3-D Image of SN1987A with ALMA

For decades, radio, optical, and even X-ray observatories have studied of SN 1987 A, but obscuring dust in the outer regions of the remnant made it difficult to analyze the supernova’s innermost core. ALMA’s ability to observe at millimeter wavelengths – a region of the electromagnetic spectrum between infrared and radio light – made it possible to see through the intervening dust and gas and study the abundance and location of newly formed molecules – especially silicon monoxide (SiO) and carbon monoxide (CO), which shine brightly at the short submillimeter wavelengths that ALMA can perceive.

In the new ALMA image and animation, emission from SiO (colored purple) and CO (colored yellow) is located in discrete clumps within the core of SN 1987A. Indebetouw said that scientists previously predicted how and where these molecules would appear, but without ALMA they were unable to capture images with high enough resolution to confirm the structure inside the remnant and test those models.

Aside from obtaining the first 3-D image of SN 1987A, the ALMA data also reveal compelling details about how the physical conditions have changed and continues to change over time. These observations also provide insights into the physical instabilities in a supernova.

New Insights from SN 1987A

Earlier observations with ALMA verified that SN 1987A produced a massive amount of dust. The new observations provide more details on how the supernova made the dust as well as the type of molecules found in it.

“One of our goals was to observe SN 1987A in a blind search for other molecules,” said Indebetouw. “We expected to find carbon monoxide and silicon monoxide, since we had previously detected these molecules.” The astronomers, however, were excited to find the previously undetected molecules HCO+ and sulfur monoxide (SO).

“These molecules had never been detected in a young supernova remnant before,” noted Indebetouw. “HCO+ is especially interesting because its formation requires particularly vigorous mixing during the explosion.”

The current observations allow the astronomers to estimate that about 1 in 1000 silicon atoms from the exploded star are now found in SiO molecules; astronomers think that the majority of the silicon is currently in dust grains. Even the small amount of SiO that is present is 100 times greater than predicted by dust formation models. These new observations will aid astronomers in refining these models.

These observations also find that 10 percent or more of the carbon in the exploded star is currently in a CO molecule. Only a few out of every million carbon atoms are in a HCO+ molecule.

New Questions and Future Research

Even though the new ALMA observations shed important light on SN 1987A, there are still several questions that remain. Exactly how abundant are the molecules of HCO+ and SO? Are there other molecules that have yet to be detected? How will the 3-D structure of SN 1987A continue to change over time?

Future ALMA observations at different wavelengths may also shed light on what sort of compact object — a pulsar or neutron star — resides at the center of this object. Such an object has been predicted but so far not detected inside SN 1987A.

There are many animations in the article which are [foolishly] in Vimeo, which I cannot reproduce. See the full article for these animations.

See the full article here .

Please help promote STEM in your local schools.

Stem Education Coalition

The Atacama Large Millimeter/submillimeter Array (ALMA), an international astronomy facility, is a partnership of Europe, North America and East Asia in cooperation with the Republic of Chile. ALMA is funded in Europe by the European Organization for Astronomical Research in the Southern Hemisphere (ESO), in North America by the U.S. National Science Foundation (NSF) in cooperation with the National Research Council of Canada (NRC) and the National Science Council of Taiwan (NSC) and in East Asia by the National Institutes of Natural Sciences (NINS) of Japan in cooperation with the Academia Sinica (AS) in Taiwan.

ALMA construction and operations are led on behalf of Europe by ESO, on behalf of North America by the National Radio Astronomy Observatory (NRAO), which is managed by Associated Universities, Inc. (AUI) and on behalf of East Asia by the National Astronomical Observatory of Japan (NAOJ). The Joint ALMA Observatory (JAO) provides the unified leadership and management of the construction, commissioning and operation of ALMA.

From ALMA: “ALMA Reveals Turbulent Birth of Twin Baby Stars”

ESO/NRAO/NAOJ ALMA Array in Chile in the Atacama at Chajnantor plateau, at 5,000 metres
ALMA

Nicolás Lira T.
Press Coordinator
Joint ALMA Observatory
Santiago, Chile
Tel: +56 2 24 67 65 19
Cell: +56 9 94 45 77 26
Email: nicolas.lira@alma.cl

Masaaki Hiramatsu
Education and Public Outreach Officer, NAOJ Chile
Observatory
Tokyo, Japan

Tel: +81 422 34 3630

E-mail: hiramatsu.masaaki@nao.ac.jp

Charles E. Blue
Public Information Officer
National Radio Astronomy Observatory
Charlottesville, Virginia, USA
Tel: +1 434 296 0314
Cell: +1 202 236 6324
E-mail: cblue@nrao.edu

Richard Hook
Public Information Officer, ESO

Garching bei München, Germany

Tel: +49 89 3200 6655

Cell: +49 151 1537 3591
Email: rhook@eso.org

Artist’s impression of the baby twin system IRAS 04191+1523. Credit: ALMA (ESO/NAOJ/NRAO)

Using the Atacama Large Millimeter/submillimeter Array (ALMA), researchers obtained a critical clue to an underlying problem: how are widely separated twin stars formed? The team found very low mass newborn twin stars with misaligned rotation axes. This misalignment indicates that they were formed in a pair of fragmented gas clouds produced through turbulence, not via evolution of tightly-coupled twin. This finding strongly supports the turbulent fragmentation theory of binary star formation down to the substellar regime.

An international team of astronomers led by Jeong-Eun Lee in Kyung Hee University, Korea, observed the baby twin star system IRAS 04191+1523 with ALMA. Thanks to the high resolution of ALMA, the team successfully imaged the rotation of the gas disks around the very low mass twin stars and found that the rotation axes of the two stars are misaligned.

“This revelation is particularly interesting because both baby stars’ masses derived from our ALMA data are about 10% of the solar mass, which is very low. The formation of very low mass wide binary stars has been a mystery. But our result is strong evidence that wide binaries of these very low mass stars and even brown dwarfs can form in the same way as normal stars via turbulent fragmentation.” said Lee.

More than a half of the stars in the Universe are born as twins or multiple systems. Therefore, unveiling the formation mechanism of twin stars is crucial for a comprehensive understanding of stellar evolution.

There are two types of multiple stars: close systems and widely separated systems. Astronomers have witnessed a close system being formed via fragmentation of the gas disk around the firstborn stars [1]. On the other hand, there is no clear evidence on how widely separated systems are formed. Some researchers assume that a close system evolves into a wide system over millions of years due to dynamical interactions, but others guess that turbulence in a gas cloud fragments the cloud into smaller ones and stars are formed in each small cloud.

Aiming to find clues to the formation of wide binary systems, the researchers selected IRAS 04191+1523 as the target of their ALMA observations. The separation of the two stars is about 30 times the distance of Neptune from the Sun and classified as a wide binary. The age of the system is estimated to be far younger than half a million years old, therefore it is a good target to investigate the initial phase of wide binary formation.

Composite image of the very young baby twin star system IRAS 04191+1523. ALMA revealed the disks around two stars (white) and a common gas envelope (yellow). Red color shows the distribution of a dense cloud seen in far infrared light observed by the Herschel Space Observatory. Credit: ALMA (ESO/NAOJ/NRAO), Lee et al., ESA/Herschel/PACS

ESA/Herschel spacecraft

The team analyzed the signal from carbon monoxide molecules in the disks to derive their motion and found that the two disks around the baby stars are not aligned. The angle between the rotation axes of the disks is 77 degrees.

“The system is too young for the alignment of axes to have been modified by interactions,” said Lee [2], “so we conclude that this system was formed by the turbulent fragmentation of a cloud, not by disk fragmentation and migration.”

If a binary system is formed via disk fragmentation, the rotational moment of the gas aligns the axes of two stars. This alignment would be maintained even if the separation between the two is extended via tidal interactions. The misalignment of the axes in the infant system IRAS 04191+1523 clearly rejects this scenario.

Notes

ALMA revealed the detailed structure of the ongoing fragmentation of a gas disk around a young triple star system L1448 IRS 3B.

Previous ALMA observations of a young binary system HK Tauri show that the two disks are misaligned. However, HK Tauri is much more evolved than IRAS 04191+1523 and it is difficult to reject the possibility of orbit evolution to become a widely-separated system.

Additional information

These observation results were published as Lee et al. Formation of Wide Binaries by Turbulent Fragmentation in Nature Astronomy on June 30, 2017.

The research team members are:

Jeong-Eun Lee (Kyung Hee University), Seokho Lee (Kyung Hee University), Michel Dunham (State University of New York at Fredonia), Ken’ichi Tatematsu (National Astronomical Observatory of Japan / SOKENDAI), Minho Choi (Korea Astronomy and Space Science Institute), Edwin A. Bergin (University of Michigan), Neal J. Evans II (Korea Astronomy and Space Science Institute / The University of Texas at Austin)

This research was supported by the Basic Science Research Program through the National Research Foundation of Korea (NRF) (grant No. NRF-2015R1A2A2A01004769) and the Korea Astronomy and Space Science Institute under the R&D program (Project No. 2015-1-320-18) supervised by the Ministry of Science, ICT and Future Planning, Korea.

See the full article here .

Please help promote STEM in your local schools.

Stem Education Coalition

The Atacama Large Millimeter/submillimeter Array (ALMA), an international astronomy facility, is a partnership of Europe, North America and East Asia in cooperation with the Republic of Chile. ALMA is funded in Europe by the European Organization for Astronomical Research in the Southern Hemisphere (ESO), in North America by the U.S. National Science Foundation (NSF) in cooperation with the National Research Council of Canada (NRC) and the National Science Council of Taiwan (NSC) and in East Asia by the National Institutes of Natural Sciences (NINS) of Japan in cooperation with the Academia Sinica (AS) in Taiwan.

ALMA construction and operations are led on behalf of Europe by ESO, on behalf of North America by the National Radio Astronomy Observatory (NRAO), which is managed by Associated Universities, Inc. (AUI) and on behalf of East Asia by the National Astronomical Observatory of Japan (NAOJ). The Joint ALMA Observatory (JAO) provides the unified leadership and management of the construction, commissioning and operation of ALMA.

From ALMA: “Chaotically Magnetized Cloud Is No Place to Build a Star, or Is It?”

ESO/NRAO/NAOJ ALMA Array in Chile in the Atacama at Chajnantor plateau, at 5,000 metres
ALMA

14 June 2017
Nicolás Lira T.
Press Coordinator
Joint ALMA Observatory
Santiago, Chile
Tel: +56 2 24 67 65 19
Cell: +56 9 94 45 77 26
Email: nicolas.lira@alma.cl

Charles E. Blue
Public Information Officer
National Radio Astronomy Observatory
Charlottesville, Virginia, USA
Tel: +1 434 296 0314
Cell: +1 202 236 6324
E-mail: cblue@nrao.edu

Masaaki Hiramatsu

Education and Public Outreach Officer, NAOJ Chile
Observatory
Tokyo, Japan

Tel: +81 422 34 3630

E-mail: hiramatsu.masaaki@nao.ac.jp

Richard Hook
Public Information Officer, ESO

Garching bei München, Germany

Tel: +49 89 3200 6655

Cell: +49 151 1537 3591
Email: rhook@eso.org

Artist impression of chaotic magnetic field lines very near a newly emerging protostar. Credit: NRAO/AUI/NSF; D. Berry

For decades, scientists believed that the magnetic field lines around a forming star were extremely powerful and orderly, warping only under extreme force and at great distance from the nascent star.

Now, a team of astronomers using the Atacama Large Millimeter/submillimeter Array (ALMA) has discovered a weak and wildly disorganized magnetic field strikingly near a newly emerging protostar. These observations suggest that the impact of magnetic fields on star formation is more complex than previously thought.

The researchers used ALMA to map the surprisingly disorganized magnetic field surrounding a young protostar dubbed Ser-emb 8, which resides about 1400 light-years away in the Serpens star-forming region. These new observations are the most sensitive ever made of the small-scale magnetic field suffusing the region surrounding a young forming star. They also provide important insights into the formation of low-mass stars like own sun.

Previous observations with other telescopes have confirmed that magnetic fields surrounding some young protostars form a classic “hourglass” shape – a hallmark of a strong magnetic field – that starts near the protostar and extends many light-years into the surrounding molecular cloud.

“Before now, we didn’t know if all stars formed in regions that were controlled by strong magnetic fields. Using ALMA, we found our answer,” said Charles L. H. “Chat” Hull, an astronomer and NRAO Jansky Fellow at the Harvard-Smithsonian Center for Astrophysics (CfA) in Cambridge, Mass., and lead author on a paper appearing in the Astrophysical Journal Letters. “We can now study magnetic fields in star-forming clouds from the broadest of scales all the way down to the forming star itself. This is exciting because it may mean stars can emerge from a wider range of conditions than we once thought.”

ALMA is able to study magnetic fields at the small scales inside star-forming clumps by mapping the polarization of light emitted by dust grains that have aligned themselves with the magnetic field.

Texture represents the magnetic field orientation in the region surrounding the Ser-emb 8 protostar, as measured by ALMA. The gray region is the millimeter wavelength dust emission. Credit: ALMA (ESO/NAOJ/NRAO); P. Mocz, C. Hull, CfA

By comparing the structure of the magnetic field in the observations with cutting-edge supercomputer simulations on multiple size scales, the astronomers gained important insights into the earliest stages of magnetized star formation. The simulations – which extend from a relatively nearby 140 astronomical units from the protostar (about 4 times the distance from the sun to Pluto) to as far out as 17 light-years – were performed by CfA astronomers Philip Mocz and Blakesley Burkhart, who are coauthors on the paper.

In the case of Ser-emb 8, the astronomers believe they have captured the original magnetic field around the protostar “red handed,” before outflowing material from the star could erase the pristine signature of the magnetic field in the surrounding molecular cloud, noted Mocz.

“Our observations show that the importance of the magnetic field in star formation can vary widely from star to star,” concluded Hull. “This protostar seems to have formed in a weakly magnetized environment dominated by turbulence, while previous observations show sources that clearly formed in strongly magnetized environments. Future studies will reveal how common each scenario is.”

Additional information

This research was presented in a paper titled Unveiling the Role of the Magnetic Field at the Smallest Scales of Star Formation, by C. Hull et al., appearing in the Astrophysical Journal Letters.

See the full article here .

Please help promote STEM in your local schools.

Stem Education Coalition

The Atacama Large Millimeter/submillimeter Array (ALMA), an international astronomy facility, is a partnership of Europe, North America and East Asia in cooperation with the Republic of Chile. ALMA is funded in Europe by the European Organization for Astronomical Research in the Southern Hemisphere (ESO), in North America by the U.S. National Science Foundation (NSF) in cooperation with the National Research Council of Canada (NRC) and the National Science Council of Taiwan (NSC) and in East Asia by the National Institutes of Natural Sciences (NINS) of Japan in cooperation with the Academia Sinica (AS) in Taiwan.

ALMA construction and operations are led on behalf of Europe by ESO, on behalf of North America by the National Radio Astronomy Observatory (NRAO), which is managed by Associated Universities, Inc. (AUI) and on behalf of East Asia by the National Astronomical Observatory of Japan (NAOJ). The Joint ALMA Observatory (JAO) provides the unified leadership and management of the construction, commissioning and operation of ALMA.

From ALMA: “Baby Star Spits a ‘Spinning Jet’ As It Munches Down on a ‘Space Hamburger’ “

ESO/NRAO/NAOJ ALMA Array in Chile in the Atacama at Chajnantor plateau, at 5,000 metres
ALMA

12 June 2017
Dr. Chin-Fei Lee
Institute of Astrophysics and Astronomy
Academia Sinica
Tel: +886-2-2366-5445
Email: cflee@asiaa.sinica.edu.tw

Nicolás Lira T.
Press Coordinator
Joint ALMA Observatory
Santiago, Chile
Tel: +56 2 24 67 65 19
Cell: +56 9 94 45 77 26
Email: nicolas.lira@alma.cl

Masaaki Hiramatsu

Education and Public Outreach Officer, NAOJ Chile
Observatory
Tokyo, Japan

Tel: +81 422 34 3630

E-mail: hiramatsu.masaaki@nao.ac.jp

Richard Hook
Public Information Officer, ESO

Garching bei München, Germany

Tel: +49 89 3200 6655

Cell: +49 151 1537 3591
Email: rhook@eso.org

Charles E. Blue
Public Information Officer
National Radio Astronomy Observatory
Charlottesville, Virginia, USA
Tel: +1 434 296 0314
Cell: +1 202 236 6324
E-mail: cblue@nrao.edu

Figure 1: Jet and disk in the HH 212 protostellar system: (a) Molecular jet (green image) ejected from the innermost part of the accretion disk (orange image), observed with ALMA at a resolution of 8 au. A dark lane is seen in the disk equator, causing the disk to appear as a “hamburger”. A size scale of our solar system is shown in the lower right corner for size comparison. (b) Split of the redshifted (turning away from us) and blueshifted (turning toward us) emission of the jet in order to show the spinning motion of the jet, as indicated by the green arrows. Blue and red arrows show the rotation of the disk, which has a direction the same as the jet rotation. Credit: ALMA (ESO/NAOJ/NRAO)/Lee et al.

Protostellar jets are seen coming out from protostars (baby stars), representing one of the most intriguing signposts of star formation. An international research team, led by Chin-Fei Lee in Academia Sinica Institute of Astronomy and Astrophysics (ASIAA, Taiwan), has made a new breakthrough observation with the Atacama Large Millimeter/submillimeter Array (ALMA), finding a protostellar jet to be spinning, convincingly for the first time. This new result confirms the expected role of the jet in removing the excess angular momentum from the innermost region of an accretion disk (space hamburger), providing a solution to the long-standing problem of how the inner accretion disk can feed a protostar.

“We see jets coming out from most of baby stars, like a train of bullets speeding down along the rotational axis of the accretion disks. We always wonder what their role is. Are they spinning, as expected in current models of jet launching? However, since the jets are very narrow and their spinning motion is very small, we had not been able to confirm their spinning motion. Now using the ALMA with its unprecedented combination of spatial and velocity resolutions, we not only resolve a jet near a protostar down to 10 astronomical units (au) but also detect its spinning motion”, says Chin-Fei Lee at ASIAA. “It looks like a baby star spits a spinning bullet each time it takes a bite of a space hamburger.”

“The central problem in forming a star is the angular momentum in the accretion disk which prevents material from falling into the central protostar. Now with the jet carrying away the excess angular momentum from the material in the innermost region of the disk, the material can readily fall into the central protostar from the disk”, says Paul Ho at ASIAA.

HH 212 is a nearby protostellar system in Orion at about 1300 lightyears. The central protostar is very young with an age of only 40,000 years (which is about 10 millionth of the age of the Sun) and a mass of only a fifth of the Sun. Recent ALMA observations at submillimeter wavelength have detected an accretion disk feeding the central protostar. The disk is nearly edge-on and has a radius of about 60 au. Interestingly, it shows a prominent equatorial dark lane sandwiched between two brighter features, appearing as a “space hamburger”.

Figure 2: A 3D cartoon showing a spinning jet coming out from an accretion disk that feeds the central protostar. (Left) The jet is spinning (as shown by the green arrows), with the blue part turning toward us and the red part turning away from us. In the disk, the blue color is cooler than the orange color. (Right) A zoom-in to the innermost region, showing the possible disk accretion and jet launching processes near the protostar. Our results imply that the jet is launched at about 0.05 au, as shown by the green arrows. The jet carries away the excess angular momentum, allowing the disk material there to fall into the central protostar, as shown by the blue arrows. As in current jet models, the jet is hollow and higher resolution is needed to check it. Credit: Lee, C.-F.

The central protostar drives a powerful bipolar jet. Previous observations at a spatial resolution of 140 au could not confirm a rotation for the jet. Now with ALMA at a resolution of 8 au, which is about 17 times higher, we zoom in to the innermost part of the jet down to within 10 au of the central protostar and find a jet rotation. The angular momentum is so small that the jet must be launched from the innermost region of the disk at about 0.05 au from the central protostar, well consistent with current models of the jet launching.

Credit: Lee, C.-F.

This new finding indicates that the jet indeed carries away part of the angular momentum (rotational momentum) from the material in the innermost region of the accretion disk (space hamburger), which is rotating around the central protostar. This reduces the rotation of the material there, allowing the disk to feed the central protostar.

These observations open an exciting possibility of detecting and measuring jet rotation around the protostars through high-resolution imaging with ALMA, which provides strong constraints on theories of jet formation in star formation. In addition, these observations also open the possibility of detecting jet rotation in other kind of objects, e.g., active nuclei of galaxies, which may play the same role of extracting disk angular momentum as the protostellar jets.

Additional information

ALMA also clearly imaged the rotation of a gas outflow from a massive protostar. (Press release ALMA Hears Birth Cry of a Massive Baby Star).

This research was presented in a paper A Rotating Protostellar Jet Launched from the Innermost Disk of HH 212, by Lee et al. to appear in the journal Nature Astronomy.

The team is composed of Chin-Fei Lee (ASIAA, Taiwan; National Taiwan University, Taiwan), Paul T.P. Ho (ASIAA, Taiwan; East Asia Observatory), Zhi-Yun Li (University of Virginia, USA), Naomi Hirano (ASIAA, Taiwan), Qizhou Zhang (Harvard-Smithsonian Center for Astrophysics, USA), and Hsien Shang (ASIAA, Taiwan).

See the full article here .

Please help promote STEM in your local schools.

Stem Education Coalition

The Atacama Large Millimeter/submillimeter Array (ALMA), an international astronomy facility, is a partnership of Europe, North America and East Asia in cooperation with the Republic of Chile. ALMA is funded in Europe by the European Organization for Astronomical Research in the Southern Hemisphere (ESO), in North America by the U.S. National Science Foundation (NSF) in cooperation with the National Research Council of Canada (NRC) and the National Science Council of Taiwan (NSC) and in East Asia by the National Institutes of Natural Sciences (NINS) of Japan in cooperation with the Academia Sinica (AS) in Taiwan.

ALMA construction and operations are led on behalf of Europe by ESO, on behalf of North America by the National Radio Astronomy Observatory (NRAO), which is managed by Associated Universities, Inc. (AUI) and on behalf of East Asia by the National Astronomical Observatory of Japan (NAOJ). The Joint ALMA Observatory (JAO) provides the unified leadership and management of the construction, commissioning and operation of ALMA.

From ALMA: “ALMA Observes Birth Cry of a Massive Baby Star”

ESO/NRAO/NAOJ ALMA Array in Chile in the Atacama at Chajnantor plateau, at 5,000 metres
ALMA

12 June 2017
Nicolás Lira T.
Press Coordinator
Joint ALMA Observatory
Santiago, Chile
Tel: +56 2 24 67 65 19
Cell: +56 9 94 45 77 26
Email: nicolas.lira@alma.cl

Masaaki Hiramatsu
Education and Public Outreach Officer, NAOJ Chile
Observatory
Tokyo, Japan

Tel: +81 422 34 3630

E-mail: hiramatsu.masaaki@nao.ac.jp

Richard Hook
Public Information Officer, ESO

Garching bei München, Germany

Tel: +49 89 3200 6655

Cell: +49 151 1537 3591
Email: rhook@eso.org

Charles E. Blue
Public Information Officer
National Radio Astronomy Observatory
Charlottesville, Virginia, USA
Tel: +1 434 296 0314
Cell: +1 202 236 6324
E-mail: cblue@nrao.edu

Figure 3. The rotation of the outflow from Orion KL Source I imaged with ALMA. The color shows the motion of the gas; red shows gas moving away from us, whereas blue shows gas moving toward us. The disk is shown in white. Credit: ALMA (ESO/NAOJ/NRAO), Hirota et al.

An international research team used the Atacama Large Millimeter/submillimeter Array (ALMA) to determine how the enigmatic gas flow from a massive baby star is launched. The astronomers observed the baby star and obtained clear evidence of rotation in the outflow. The motion and the shape of the outflow indicate that the interplay of centrifugal and magnetic forces in a disk surrounding the star plays a crucial role in the star’s birth cry.

Stars form from gas and dust floating in interstellar space. But, astronomers do not yet fully understand how it is possible to form the massive stars seen in space. One key issue is gas rotation. The parent cloud rotates slowly in the initial stage and the rotation becomes faster as the cloud shrinks due to self-gravity. Stars formed in such a process should have very rapid rotation, but this is not the case. The stars observed in the Universe rotate more slowly.

How is the rotational momentum dissipated? One possible scenario involves that the gas emanating from baby stars. If the gas outflow rotates, it can carry rotational momentum away from the system. Astronomers have tried to detect the rotation of the outflow to test this scenario and understand its launching mechanism. In a few cases signatures of rotation have been found, but it has been difficult to resolve clearly, especially around massive baby stars.

Figure 1. Artist’s impression of Orion KL Source I. The massive protostar is surrounded by a disk of gas and dust. The outflow is launched from the surface of the outer disk. Credit: ALMA (ESO/NAOJ/NRAO)

The team of astronomers led by Tomoya Hirota, an assistant professor at the National Astronomical Observatory of Japan (NAOJ) and SOKENDAI (the Graduate University for Advanced Studies) observed a massive baby star called Orion KL Source I in the famous Orion Nebula, located 1,400 light-years away from the Earth. The Orion Nebula is the closest massive-star forming region to Earth. Thanks to its close vicinity and ALMA’s advanced capabilities, the team could reveal the nature of the outflow from Source I.

“We have clearly imaged the rotation of the outflow,” said Hirota, the lead author of the research paper published in the journal Nature Astronomy. “In addition, the result gives us important insight into the launching mechanism of the outflow.”

The new ALMA observations beautifully illustrate the rotation of the outflow, in the same direction as the gas disk surrounding the star. This strongly supports the idea that the outflow plays an important role in dissipating the rotational energy.

Figure 2. Orion KL Source I observed with ALMA. The massive protostar is in the center and surrounded by a gas disk (red). A bipolar gas outflow is ejected from the protostar (blue). Credit: ALMA (ESO/NAOJ/NRAO), Hirota et al.

Furthermore, ALMA clearly shows that the outflow is launched not from the vicinity of the baby star itself, but rather from the outer edge of the disk. This morphology agrees well with the “magnetocentrifugal disk wind model.” In this model, gas in the rotating disk moves outward due to the centrifugal force and then moves upward along the magnetic field lines to form outflows. Although previous observations with ALMA have found supporting evidence around a low-mass protostar, there was little compelling evidence around massive protostars because most of the massive-star forming regions are rather distant and difficult to investigate in detail.

“In addition to high sensitivity and fidelity, high resolution submillimeter-wave observation is essential to our study, which ALMA made possible for the first time. Submillimeter waves are a unique diagnostic tool for the dense innermost region of the outflow, and at that exact place we detected the rotation,” explained Hirota. “ALMA’s resolution will become even higher in the future. We would like to observe other objects to improve our understanding of the launching mechanism of outflows and the formation scenario of massive stars with the assistance of theoretical research.”

Additional information

ALMA also imaged rotation of a gas jet from a low-mass protostar. Please read the press release Baby Star Spits a ‘Spinning Jet’ As It Munches -Down on a ‘Space Hamburger’ from the Academia Sinica Institute of Astronomy and Astrophysics, Taiwan.

These observation results were published as Hirota et al. Disk-Driven Rotating Bipolar Outflow in Orion Source I in Nature Astronomy on June 12, 2017.

The research team members are:

Tomoya Hirota (National Astronomical Observatory of Japan / SOKENDAI), Masahiro Machida (Kyushu University), Yuko Matsushita (Kyushu University), Kazuhito Motogi (Yamaguchi University / NAOJ), Naoko Matsumoto (Yamaguchi University / NAOJ), Mi Kyoung Kim (Korean Astronomy and Space Science Institute), Ross A. Burns (Joint Institute for VLBI ERIC), Mareki Honma (NAOJ/SOKENDAI)

This research was supported by Grants-in-Aid from the Japan Society for the Promotion of Science and the Ministry of Education, Culture, Sports, Science and Technology, Japan (No. 21224002、 24684011、25108005、15H03646、15K17613、24540242、25120007).

See the full article here .

Please help promote STEM in your local schools.

Stem Education Coalition

The Atacama Large Millimeter/submillimeter Array (ALMA), an international astronomy facility, is a partnership of Europe, North America and East Asia in cooperation with the Republic of Chile. ALMA is funded in Europe by the European Organization for Astronomical Research in the Southern Hemisphere (ESO), in North America by the U.S. National Science Foundation (NSF) in cooperation with the National Research Council of Canada (NRC) and the National Science Council of Taiwan (NSC) and in East Asia by the National Institutes of Natural Sciences (NINS) of Japan in cooperation with the Academia Sinica (AS) in Taiwan.

ALMA construction and operations are led on behalf of Europe by ESO, on behalf of North America by the National Radio Astronomy Observatory (NRAO), which is managed by Associated Universities, Inc. (AUI) and on behalf of East Asia by the National Astronomical Observatory of Japan (NAOJ). The Joint ALMA Observatory (JAO) provides the unified leadership and management of the construction, commissioning and operation of ALMA.

From ALMA: “ALMA Finds Ingredient of Life Around Infant Sun-like Stars”

ESO/NRAO/NAOJ ALMA Array in Chile in the Atacama at Chajnantor plateau, at 5,000 metres
ALMA

8 June 2017
Rafael Martín-Doménech
Centro de Astrobiología
Madrid, Spain
Email: rmartin@cab.inta-csic.es

Victor Rivilla
INAF-Osservatorio Astrofisico di Arcetri
Italy
Email: rivilla@arcetri.astro.it

Audrey Coutens
Laboratoire d’Astrophysique de Bordeaux
France
Email: audrey.coutens@u-bordeaux.fr

Niels Ligterink
Sackler Laboratory for Astrophysics, Leiden Observatory
Netherlands
Tel: +31 (0) 71 527 5844
Email: ligterink@strw.leidenuniv.nl

Nicolás Lira T.
Press Coordinator
Joint ALMA Observatory
Santiago, Chile
Tel: +56 2 24 67 65 19
Cell: +56 9 94 45 77 26
Email: nicolas.lira@alma.cl

Richard Hook
Public Information Officer, ESO

Garching bei München, Germany

Tel: +49 89 3200 6655

Cell: +49 151 1537 3591
Email: rhook@eso.org

Charles E. Blue
Public Information Officer
National Radio Astronomy Observatory
Charlottesville, Virginia, USA
Tel: +1 434 296 0314
Cell: +1 202 236 6324
E-mail: cblue@nrao.edu

Masaaki Hiramatsu

Education and Public Outreach Officer, NAOJ Chile
Observatory
Tokyo, Japan

Tel: +81 422 34 3630

E-mail: hiramatsu.masaaki@nao.ac.jp

ALMA has observed stars like the Sun at a very early stage in their formation and found traces of methyl isocyanate — a chemical building block of life. This is the first ever detection of this prebiotic molecule towards solar-type protostars, the sort from which our Solar System evolved. The discovery could help astronomers understand how life arose on Earth.

Two teams of astronomers have harnessed the power of the Atacama Large Millimeter/submillimeter Array (ALMA) in Chile to detect the prebiotic complex organic molecule methyl isocyanate [1] in the multiple star system IRAS 16293-2422. One team was co-led by Rafael Martín-Doménech at the Centro de Astrobiología in Madrid, Spain, and Víctor M. Rivilla, at the INAF-Osservatorio Astrofisico di Arcetri in Florence, Italy; and the other by Niels Ligterink at the Leiden Observatory in the Netherlands and Audrey Coutens at University College London, United Kingdom.

“This star system seems to keep on giving! Following the discovery of sugars, we’ve now found methyl isocyanate. This family of organic molecules is involved in the synthesis of peptides and amino acids, which, in the form of proteins, are the biological basis for life as we know it,” explain Niels Ligterink and Audrey Coutens [2].

ALMA’s capabilities allowed both teams to observe the molecule at several different and characteristic wavelengths across the radio spectrum [3]. They found the unique chemical fingerprints located in the warm, dense inner regions of the cocoon of dust and gas surrounding young stars in their earliest stages of evolution. Each team identified and isolated the signatures of the complex organic molecule methyl isocyanate [4]. They then followed this up with computer chemical modelling and laboratory experiments to refine our understanding of the molecule’s origin [5].

IRAS 16293-2422 is a multiple system of very young stars, around 400 light-years away in a large star-forming region called Rho Ophiuchi in the constellation of Ophiuchus (The Serpent Bearer). The new results from ALMA show that methyl isocyanate gas surrounds each of these young stars.

The Rho Ophiuchi star formation region in the constellation of Ophiuchus

Earth and the other planets in our Solar System formed from the material left over after the formation of the Sun. Studying solar-type protostars can therefore open a window to the past for astronomers and allow them to observe conditions similar to those that led to the formation of our Solar System over 4.5 billion years ago.

Rafael Martín-Doménech and Víctor M. Rivilla, lead authors of one of the papers, comment: “We are particularly excited about the result because these protostars are very similar to the Sun at the beginning of its lifetime, with the sort of conditions that are well suited for Earth-sized planets to form. By finding prebiotic molecules in this study, we may now have another piece of the puzzle in understanding how life came about on our planet.”

Niels Ligterink is delighted with the supporting laboratory results: “Besides detecting molecules we also want to understand how they are formed. Our laboratory experiments show that methyl isocyanate can indeed be produced on icy particles under very cold conditions that are similar to those in interstellar space This implies that this molecule — and thus the basis for peptide bonds — is indeed likely to be present near most new young solar-type stars.”

Notes

[1] A complex organic molecule is defined in astrochemistry as consisting of six or more atoms, where at least one of the atoms is carbon. Methyl isocyanate contains carbon, hydrogen, nitrogen and oxygen atoms in the chemical configuration CH3NCO. This very toxic substance was the main cause of death following the tragic Bhopal industrial accident in 1984.

[2] The system was previously studied by ALMA in 2012 and found to contain molecules of the simple sugar glycolaldehyde, another ingredient for life.

[3] The team led by Rafael Martín-Doménech used new and archive data of the protostar taken across a large range of wavelengths across ALMA’s receiver Bands 3, 4 and 6. Niels Ligterink and his colleagues used data from the ALMA Protostellar Interferometric Line Survey (PILS), which aims to chart the chemical complexity of IRAS 16293-2422 by imaging the full wavelength range covered by ALMA’s Band 7 on very small scales, equivalent to the size of our Solar System.

[4] The teams carried out spectrographic analysis of the protostar’s light to determine the chemical constituents. The amount of methyl isocyanate they detected — the abundance — with respect to molecular hydrogen and other tracers is comparable to previous detections around two high-mass protostars (i.e. within the massive hot molecular cores of Orion KL and Sagittarius B2 North).

[5] Martín-Doménech’s team chemically modelled gas-grain formation of methyl isocyanate. The observed amount of the molecule could be explained by chemistry on the surface of dust grains in space, followed by chemical reactions in the gas phase. Moreover, Ligterink’s team demonstrated that the molecule can be formed at extremely cold interstellar temperatures, down to 15 Kelvin (–258 degrees Celsius), using cryogenic ultra-high-vacuum experiments in their laboratory in Leiden.

More information

This research was presented in two papers: First Detection of Methyl Isocyanate (CH3NCO) in a solar-type Protostar by R. Martín-Doménech et al. and The ALMA-PILS survey: Detection of CH3NCO toward the low-mass protostar IRAS 16293-2422 and laboratory constraints on its formation, by N. F. W. Ligterink et al.. Both papers will appear in the same issue of the Monthly Notices of the Royal Astronomical Society.

One team is composed of: R. Martín-Doménech (Centro de Astrobiología, Spain), V. M. Rivilla (INAF-Osservatorio Astrofisico di Arcetri, Italy), I. Jiménez-Serra (Queen Mary University of London, UK), D. Quénard (Queen Mary University of London, UK), L. Testi (INAF-Osservatorio Astrofisico di Arcetri, Italy; ESO, Garching, Germany; Excellence Cluster “Universe”, Germany) and J. Martín-Pintado (Centro de Astrobiología, Spain).

The other team is composed of: N. F. W. Ligterink (Sackler Laboratory for Astrophysics, Leiden Observatory, the Netherlands), A. Coutens (University College London, UK), V. Kofman (Sackler Laboratory for Astrophysics, The Netherlands), H. S. P. Müller (Universität zu Köln, Germany), R. T. Garrod (University of Virginia, USA), H. Calcutt (Niels Bohr Institute & Natural History Museum, Denmark), S. F. Wampfler (Center for Space and Habitability, Switzerland), J. K. Jørgensen (Niels Bohr Institute & Natural History Museum, Denmark), H. Linnartz (Sackler Laboratory for Astrophysics, The Netherlands) and E. F. van Dishoeck (Leiden Observatory, The Netherlands; Max-Planck-Institut für Extraterrestrische Physik, Germany).

The Atacama Large Millimeter/submillimeter Array (ALMA), an international astronomy facility, is a partnership of the European Organisation for Astronomical Research in the Southern Hemisphere (ESO), the U.S. National Science Foundation (NSF) and the National Institutes of Natural Sciences (NINS) of Japan in cooperation with the Republic of Chile. ALMA is funded by ESO on behalf of its Member States, by NSF in cooperation with the National Research Council of Canada (NRC) and the National Science Council of Taiwan (NSC) and by NINS in cooperation with the Academia Sinica (AS) in Taiwan and the Korea Astronomy and Space Science Institute (KASI).

ALMA construction and operations are led by ESO on behalf of its Member States; by the National Radio Astronomy Observatory (NRAO), managed by Associated Universities, Inc. (AUI), on behalf of North America; and by the National Astronomical Observatory of Japan (NAOJ) on behalf of East Asia. The Joint ALMA Observatory (JAO) provides the unified leadership and management of the construction, commissioning and operation of ALMA..

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The Atacama Large Millimeter/submillimeter Array (ALMA), an international astronomy facility, is a partnership of Europe, North America and East Asia in cooperation with the Republic of Chile. ALMA is funded in Europe by the European Organization for Astronomical Research in the Southern Hemisphere (ESO), in North America by the U.S. National Science Foundation (NSF) in cooperation with the National Research Council of Canada (NRC) and the National Science Council of Taiwan (NSC) and in East Asia by the National Institutes of Natural Sciences (NINS) of Japan in cooperation with the Academia Sinica (AS) in Taiwan.

ALMA construction and operations are led on behalf of Europe by ESO, on behalf of North America by the National Radio Astronomy Observatory (NRAO), which is managed by Associated Universities, Inc. (AUI) and on behalf of East Asia by the National Astronomical Observatory of Japan (NAOJ). The Joint ALMA Observatory (JAO) provides the unified leadership and management of the construction, commissioning and operation of ALMA.