From ALMA: “Event Horizon Telescope Images of a Black-Hole Powered Jet”

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

From ALMA

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

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

Bárbara Ferreira
ESO Public Information Officer
Garching bei München, Germany
Phone: +49 89 3200 6670
Email: pio@eso.org

Iris Nijman
Public Information Officer
National Radio Astronomy Observatory Charlottesville, Virginia – USA
Cell phone: +1 (434) 249 3423
Email: alma-pr@nrao.edu

Illustration of multiwavelength 3C 279 jet structure in April 2017. The observing epochs, arrays, and wavelengths are noted at each panel. Credit: J.Y. Kim (MPIfR), Boston University Blazar Program (VLBA and GMVA), and Event Horizon Telescope Collaboration.

Something is Lurking in the Heart of Quasar 3C 279. One year ago, the Event Horizon Telescope (EHT) Collaboration published the first image of a black hole in the nearby radio galaxy Messier 87.

Mesier 87*, The first image of a black hole. This is the supermassive black hole at the center of the galaxy Messier 87. Image via JPL/ Event Horizon Telescope Collaboration.

Now the collaboration has extracted new information from the EHT data of the far quasar 3C 279: they observed in the finest detail ever a relativistic jet that is believed to originate from the vicinity of a supermassive black hole. In their analysis, which was led by astronomer Jae-Young Kim from the Max Planck Institute for Radio Astronomy in Bonn, they studied the jet’s fine-scale morphology close to the jet base where highly variable gamma-ray emission is thought to originate. The technique used for observing the jet is called very long baseline interferometry (VLBI). The results are published in the coming issue of “Astronomy & Astrophysics”, April 2020.

The EHT collaboration continues extracting information from the groundbreaking data collected in its global campaign in April 2017. One target of the observations was the quasar 3C 279, a galaxy 5 billion light-years away, in the constellation Virgo that scientists classify as a quasar because a point of light at its center shines ultra-bright and flickers as massive amounts of gases and stars fall into the giant black hole there. The black hole is about one billion times the mass of the Sun, that is, 200 more massive than our Galactic Centre black hole. It is shredding the gas and stars that come near into an inferred accretion disk and we see it is squirting some of the gas back out in two fine fire-hose-like jets of plasma at velocities approaching the speed of light. This tells of enormous forces at play in the center.

The EHT collaboration continues extracting information from the groundbreaking data collected in its global campaign in April 2017. One target of the observations was the quasar 3C 279, a galaxy 5 billion light-years away, in the constellation Virgo that scientists classify as a quasar because a point of light at its center shines ultra-bright and flickers as massive amounts of gases and stars fall into the giant black hole there. The black hole is about one billion times the mass of the Sun, that is, 200 more massive than our Galactic Centre black hole. It is shredding the gas and stars that come near into an inferred accretion disk and we see it is squirting some of the gas back out in two fine fire-hose-like jets of plasma at velocities approaching the speed of light. This tells of enormous forces at play in the center.

The interpretation of the observations is challenging. Motions different than the jet direction, and apparently as fast as about 20 times the speed of light are difficult to reconcile with the early understanding of the source, this suggests traveling shocks or instabilities in a bent, possibly rotating jet, which also emits at high energies, such gamma-rays.

The telescopes contributing to this result were ALMA, APEX, the IRAM 30-meter telescope, the James Clerk Maxwell Telescope, the Large Millimeter Telescope, the Submillimeter Array, the Submillimeter Telescope, and the South Pole Telescope.

The telescopes work together using a technique called very long baseline interferometry (VLBI). This synchronizes facilities around the world and exploits the rotation of our planet to form one huge, Earth-size telescope. VLBI allows the EHT to achieve a resolution of 20 micro-arcseconds — equivalent to identifying an orange on Earth as seen by an astronaut from the Moon. The data analysis to transform raw data to an image required specific computers (or correlators), hosted by the MPIfR in Bonn and the MIT Haystack Observatory.

Anton Zensus, Director at the MPIfR and Chair of the EHT Collaboration Board, stresses the achievement as a global effort: “Last year we could present the first image of the shadow of a black hole. Now we see unexpected changes in the shape of the jet in 3C 279, and we are not done yet. We are working on the analysis of data from the centre of our Galaxy in Sgr A*, and on other active galaxies such as Centaurus A, OJ 287, and NGC 1052. As we told last year: this is just the beginning.”

Opportunities to conduct EHT observing campaigns occur once a year in early Northern springtime, but the March/April 2020 campaign had to be cancelled in response to the CoViD-19 global outbreak. In announcing the cancellation Michael Hecht, astronomer from the MIT/Haystack Observatory and EHT Deputy Project Director, concluded that: “We will now devote our full concentration to completion of scientific publications from the 2017 data and dive into the analysis of data obtained with the enhanced EHT array in 2018. We are looking forward to observations with the EHT array expanded to eleven observatories in the spring of 2021”.

Additional Information

The Event Horizon Telescope international collaboration announced the first-ever image of a black hole at the heart of the radio galaxy Messier 87 on April 10, 2019 by creating a virtual Earth-sized telescope. Supported by considerable international investment, the EHT links existing telescopes using novel systems — creating a new instrument with the highest angular resolving power that has yet been achieved.

The individual telescopes involved in the EHT collaboration are: the Atacama Large Millimetre Telescope (ALMA), the Atacama Pathfinder EXplorer (APEX), the Greenland Telescope (since 2018), the IRAM 30-meter Telescope, the IRAM NOEMA Observatory (expected 2021), the Kitt Peak Telescope (expected 2021), the James Clerk Maxwell Telescope (JCMT), the Large Millimeter Telescope (LMT), the Submillimeter Array (SMA), the Submillimeter Telescope (SMT), and the South Pole Telescope (SPT).

The EHT consortium consists of 13 stakeholder institutes; the Academia Sinica Institute of Astronomy and Astrophysics, the University of Arizona, the University of Chicago, the East Asian Observatory, Goethe-Universität Frankfurt, Institut de Radioastronomie Millimétrique, Large Millimeter Telescope, Max-Planck-Institut für Radioastronomie, MIT Haystack Observatory, National Astronomical Observatory of Japan, Perimeter Institute for Theoretical Physics, Radboud University and the Smithsonian Astrophysical Observatory.

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 ESOblog: “From the ground to the sky”

From ESOblog

27 March 2020. People@ESO.

As well as being an Operations Astronomer at the ESO ALMA Regional Centre, María Díaz Trigo is a world-renowned expert in high-energy astrophysics and lends her expertise to X-ray space missions. In this week’s blog post, we find out what Maria does on a daily basis, how she fits everything in, and why she thinks it’s important that ground- and space-based astronomy evolve in parallel.

María Díaz Trigo

Artist”s impression of the black holes studied by the astronomers, using ULTRACAM attached to ESO’s Very Large Telescope [below]. The systems — designated Swift J1753.5-0127 and GX 339-4 — each contain a black hole and a normal star separated by a few million kilometres. That’s less than 10 percent of the distance between Mercury and our Sun. Because the two objects are so close to each other, a stream of matter spills from the normal star toward the black hole and forms a disc of hot gas around it. As matter collides in this so-called accretion disc, it heats up to millions of degrees. Near the black hole, intense magnetic fields in the disc accelerate some of this hot gas into tight jets that flow in opposite directions away from the black hole. The orbital period of Swift J1753.5-0127 — just 3.2 hours — is the fastest found for a black hole. The orbital period of GX 339-4, by contrast, is about 1.7 days. Credit: ESO/L. Calçada.

Q. Firstly, could you tell us a bit about your role at ESO? What do you do on a daily basis?

A. I’m an ALMA astronomer, meaning half of my time is dedicated to ALMA Observatory duties.

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

This spans a range of activities, including scheduling different projects to happen at the right time, under the right conditions.

The other half of my time is spent on my own research, where I am really free to work on whatever I want. So I focus on X-ray binary systems, which consist of either a small black hole (by which I mean around ten times the mass of the Sun!) or a neutron star, as well as a normal star. The black hole or neutron star pulls matter from the normal star. This process, called accretion, powers the most energetic phenomena in the Universe and releases a lot of X-rays. These X-rays can be observed using dedicated space telescopes, and I look at these X-ray observations together with observations of the same systems in other wavelengths of light made by telescopes on the ground. This gives me a lot of information about what’s going on in different parts of the system.

Q. What first got you interested in astronomy?

A. At university I specialised in particle physics, but after my master’s degree, particle physics seemed to be at the stage where the most exciting science had already been done. It is also difficult to work on your own research in particle physics; everything needs big expensive particle accelerators and extensive collaborations. So I switched to astronomy because of the amazing number of things that can be done with telescopes — both by collecting new data and by analysing data that already exist.

This artist’s impression shows the surroundings of a supermassive black hole, typical of that found at the heart of many galaxies. The black hole itself is surrounded by a brilliant accretion disc of very hot, infalling material and, further out, a dusty torus. There are also often high-speed jets of material ejected at the black hole’s poles that can extend huge distances into space. Observations with ALMA have detected a very strong magnetic field close to the black hole at the base of the jets and this is probably involved in jet production and collimation. Credit: ESO/L. Calçada.

Q. And you are now an expert in high-energy astrophysics. Could you tell us a bit more about your research and why it inspires you?

A. When a black hole or neutron star in a binary system pulls matter from a companion star, a disc forms around the black hole or neutron star, consisting of matter dragged off of the companion star, and this is what feeds the heavier object. At some point this disc is heated so much that the upper layers evaporate and matter flies away from the system in the form of winds. These winds have speeds of the order of 1000 km/s and are detected predominantly in X-rays and sometimes with telescopes that observe optical light. However, these winds are “slow” compared to the very narrow, collimated, extremely high-speed jets that are also expelled from the system and detected from radio to infrared wavelengths.

I study these winds and jets and try to figure out how they fit in with the rest of the system. One of the biggest mysteries is how to feed black holes so that they get as big as those found at the centres of galaxies, which weigh as much as millions of Suns. Even if black holes are attracting matter from gas and stars, it seems as if a significant part of that matter is ejected in winds and possibly jets before it even gets to the black hole, so we’re still wondering how matter actually reaches the black hole so it can grow.

Q. How does this research fit in with being a European Participating Scientist for JAXA’s X-ray Imaging and Spectroscopy Mission (XRISM)? Why did you choose to take on this role?

Artist’s impression of the JAXA/NASA X-ray Imaging and Spectroscopy Mission (XRISM).
Credit: JAXA

A. Well, I wanted to contribute to making the mission a success in getting us to the next stage of X-ray instrumentation! XRISM is a JAXA/NASA collaborative mission, with participation from the European Space Agency (ESA). It will carry a revolutionary micro-calorimeter providing a spectral resolution higher than conventional X-ray imaging spectrometers by a factor of 30. A micro-calorimeter will also be flown on ESA’s next large X-ray space mission Athena and we hope to learn lots of lessons from XRISM!

I was selected by ESA around two years ago to represent the European scientific community on XRISM, and I mostly contribute scientific expertise in the area of X-ray binaries. I meet with a whole group of participating scientists every six months in person and monthly remotely, and we form part of the mission’s science team. We are currently considering which X-ray-emitting objects we should observe during the first six months after XRISM is launched in 2022, which will be the performance verification phase. During this period we will use the telescope to observe lots of different sources to check how the instrument fares — where it works well and where it works less well — so that the science community can prepare their own observations for the operational phase.

Q. Do you think it’s important that ground-based astronomy and space-based astronomy evolve in parallel, with astronomers from both areas working together? If so, why?

A. Absolutely! Astronomy is a complex science and one telescope observing one wavelength of light is not enough to have a full picture of what’s going on out there in the Universe. For example, one mystery surrounding black holes is that the supermassive black holes at the centre of galaxies emit X-rays, and so do the little black holes that I observe in binary systems, but medium-sized black holes don’t emit any X-rays! We didn’t even know whether these medium-sized black holes existed until gravitational waves allowed us to detect them for the first time. Now we can find out more about them and figure out why we don’t see any X-rays from them.

Q. And what about collaboration between different scientific organisations? Why is this important?

A. Knowledge sharing is always important. ESO and ESA have an ongoing collaboration to share knowledge and experience in the areas of science, technology and operations. This is mostly done through a working group for each of the three areas. I am part of the science working group in which we try to see where we can collaborate to advance scientific projects. For example, for some ESA space missions to achieve their full science goals, their observations are followed up by ESO’s ground-based telescopes.

ALMA itself is a partnership between ESO, the US National Science Foundation, and Japan’s National Institute of Natural Sciences in cooperation with the Republic of Chile. So representatives from most continents are involved and the telescope is showing what can be achieved through a global collaboration. It’s hard work but very, very rewarding.

Space missions are also becoming more complex and expensive, making it difficult for one agency alone to build and fund them. Costs and expertise have to be shared; this is demonstrated in XRISM where expertise comes from scientists around the world.

Q. It sounds like you’ve got a lot on your plate! How do you fit everything in?

A. (María laughs) I do what I can! It is a lot, but it’s one of the challenges that comes with working in science. The 50% of time many scientists have available to spend on “‘science” is not really all “own research time” in the end. We have to do a lot of work for the community otherwise the community can’t move forward. Being involved in advisory committees or selecting proposals from other scientists for observations with a given telescope indeed leaves less time for research, but it means that we extend and share our expertise.

For example, for XRISM I contribute my knowledge about X-ray binaries, but there are so many other objects out there that emit X-rays. I’ve recently been learning from cosmological experts who work on very, very distant X-ray-emitting clusters of galaxies.

Q. Finally, you’ve also got a degree in philosophy. How does that fit in with your interests in physics and understanding the Universe?

A. Aside from being influenced by a fantastic teacher, I was always very attracted by philosophy because it’s at the core of thinking. Centuries ago, philosophers were the physicists of their times – their aim was to understand the Universe. Nowadays unfortunately we’re locked into small areas of expertise making it difficult to see the bigger picture. I found this very unsatisfactory; I can do many things to better understand my little black holes but in the end our aim is to discover why we are here and where we go now. I can’t answer these questions with my data alone.

Seeing the bigger picture gives us a direction, something to aim for. Fortunately, we are now moving in the direction of multidisciplinary work; people from different areas are working together and combining their knowledge to solve bigger problems.

See the full article here .

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ESO is the foremost intergovernmental astronomy organisation in Europe and the world’s most productive ground-based astronomical observatory by far. It is supported by 16 countries: Austria, Belgium, Brazil, the Czech Republic, Denmark, France, Finland, Germany, Italy, the Netherlands, Poland, Portugal, Spain, Sweden, Switzerland and the United Kingdom, along with the host state of Chile. ESO carries out an ambitious programme focused on the design, construction and operation of powerful ground-based observing facilities enabling astronomers to make important scientific discoveries. ESO also plays a leading role in promoting and organising cooperation in astronomical research. ESO operates three unique world-class observing sites in Chile: La Silla, Paranal and Chajnantor. At Paranal, ESO operates the Very Large Telescope, the world’s most advanced visible-light astronomical observatory and two survey telescopes. VISTA works in the infrared and is the world’s largest survey telescope and the VLT Survey Telescope is the largest telescope designed to exclusively survey the skies in visible light. ESO is a major partner in ALMA, the largest astronomical project in existence. And on Cerro Armazones, close to Paranal, ESO is building the 39-metre European Extremely Large Telescope, the E-ELT, which will become “the world’s biggest eye on the sky”.

ESO VLT at Cerro Paranal in the Atacama Desert, •ANTU (UT1; The Sun ),
•KUEYEN (UT2; The Moon ),
•MELIPAL (UT3; The Southern Cross ), and
•YEPUN (UT4; Venus – as evening star).
elevation 2,635 m (8,645 ft) from above Credit J.L. Dauvergne & G. Hüdepohl atacama photo,

Glistening against the awesome backdrop of the night sky above ESO_s Paranal Observatory, four laser beams project out into the darkness from Unit Telescope 4 UT4 of the VLT, a major asset of the Adaptive Optics system

ESO/Cerro LaSilla 600 km north of Santiago de Chile at an altitude of 2400 metres.

ESO VLT 4 lasers on Yepun

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

ESO/NTT at Cerro LaSilla 600 km north of Santiago de Chile at an altitude of 2400 metres.

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

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

ESO/E-ELT,to be on top of Cerro Armazones in the Atacama Desert of northern Chile. located at the summit of the mountain at an altitude of 3,060 metres (10,040 ft).

ESO/MPIfR APEX high on the Chajnantor plateau in Chile’s Atacama region, at an altitude of over 4,800 m (15,700 ft)at the Llano de Chajnantor Observatory in the Atacama desert.

A novel gamma ray telescope under construction on Mount Hopkins, Arizona. a large project known as the Cherenkov Telescope Array, composed of hundreds of similar telescopes to be situated in the Canary Islands and Chile. The telescope on Mount Hopkins will be fitted with a prototype high-speed camera, assembled at the University of Wisconsin–Madison, and capable of taking pictures at a billion frames per second. Credit: Vladimir Vassiliev

From ALMA: “ALMA Resolves Gas Impacted by Young Jets from Supermassive Black Hole”

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

From ALMA

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

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

Bárbara Ferreira
ESO Public Information Officer
Garching bei München, Germany
Phone: +49 89 3200 6670
Email: pio@eso.org

Iris Nijman
Public Information Officer
National Radio Astronomy Observatory Charlottesville, Virginia – USA
Cell phone: +1 (434) 249 3423
Email: alma-pr@nrao.edu

Reconstructed images of what MG J0414+0534 would look like if gravitational lensing effects were turned off. The emissions from dust and ionized gas around a quasar　are shown in red. The emissions from carbon monoxide gas are shown in green, which have a bipolar structure along the jets. Credit: ALMA (ESO/NAOJ/NRAO), K. T. Inoue et al.

ALMA image of MG J0414+0534 (emissions from dust and ionized gas shown in red and emissions from carbon monoxide gas shown in green). Credit: ALMA (ESO/NAOJ/NRAO), K. T. Inoue at al.

Artist’s impression of MG J0414+0534. The central supermassive black hole has just emitted powerful jets, which are disturbing the surrounding gas in the host galaxy. Credit: Kindai University

Astronomers obtained the first resolved image of disturbed gaseous clouds in a galaxy 11 billion light-years away by using the Atacama Large Millimeter/submillimeter Array (ALMA). The team found that the disruption is caused by young powerful jets ejected from a supermassive black hole residing at the center of the host galaxy. This result will cast light on the mystery of the evolutionary process of galaxies in the early Universe.

It is commonly known that black holes exert strong gravitational attraction on surrounding matter. However, it is less well known that some black holes have fast-moving streams of ionized matter, called jets. In some nearby galaxies, evolved jets blow off galactic gaseous clouds, resulting in suppressed star formation. Therefore, to understand the evolution of galaxies, it is crucial to observe the interaction between black hole jets and gaseous clouds throughout cosmic history. However, it had been difficult to obtain clear evidence of such interaction, especially in the early Universe.

In order to obtain such clear evidence, the team used ALMA to observe an interesting object known as MG J0414+0534. A distinctive feature of MG J0414+0534 is that the paths of light traveling from it to Earth are significantly distorted by the gravity of another ‘lensing’ galaxy between MG J0414+0534 and us, causing significant magnification.

“This distortion works as a ‘natural telescope’ to enable a detailed view of distant objects,” says Takeo Minezaki, an associate professor at the University of Tokyo.

Another feature is that MG J0414+0534 has a supermassive black hole with bipolar jets at the center of the host galaxy. The team was able to reconstruct the ‘true’ image of gaseous clouds as well as the jets in MG J0414+0534 by carefully accounting for the gravitational effects exerted by the intervening lensing galaxy.

“Combining this cosmic telescope and ALMA’s high-resolution observations, we obtained exceptionally sharp vision, that is 9,000 times better than human eyesight,” adds Kouichiro Nakanishi, a project associate professor at the National Astronomical Observatory of Japan/SOKENDAI. “With this extremely high resolution, we were able to obtain the distribution and motion of gaseous clouds around jets ejected from a supermassive black hole.”

Thanks to such a superior resolution, the team found that gaseous clouds along the jets have violent motion with speeds as high as 600 km/s, showing clear evidence of impacted gas. Moreover, it turned out that the size of the impacted gaseous clouds and the jets are much smaller than the typical size of a galaxy at this age.

“We are perhaps witnessing the very early phase of jet evolution in the galaxy,” says Satoki Matsushita, a research fellow at Academia Sinica Institute of Astronomy and Astrophysics. “It could be as early as several tens of thousands of years after the launch of the jets.”

“MG J0414+0534 is an excellent example because of the youth of the jets,” summarizes Kaiki Inoue, a professor at Kindai University, Japan, and the lead author of the research paper which appeared in the Astrophysical Journal Letters. “We found telltale evidence of significant interaction between jets and gaseous clouds even in the very early evolutionary phase of jets. I think that our discovery will pave the way for a better understanding of the evolutionary process of galaxies in the early Universe.”
Additional Information

These observation results are presented in K. T. Inoue et al. “ALMA 50-parsec resolution imaging of jet-ISM interaction in the lensed quasar MG J0414+0534” appeared in The Astrophysical Journal Letters on March 27, 2020.

The research team members are Kaiki T. Inoue (Kindai University), Satoki Matsushita (Academia Sinica Institute of Astronomy and Astrophysics), Kouichiro Nakanishi (National Astronomical Observatory of Japan/SOKENDAI), and Takeo Minezaki (The University of Tokyo).

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 AAS NOVA: “Featured Image: Evidence for Planets in Disks?”

From AAS NOVA

23 March 2020
Susanna Kohler

Disk Substructures at High Angular Resolution Project (DSHARP) ESO/ALMA

Are baby planets responsible for the gaps and rings we’ve spotted in the disks that surround distant, young stars? A new study led by Christophe Pinte (Monash University, Australia; Univ. Grenoble Alpes, France) has found evidence supporting this theory in the images of eight circumstellar disks observed in the Disk Substructures at High Angular Resolution (DSHARP) project. DSHARP uses the Atacama Large Millimeter/submillimeter Array (ALMA) to explore the gas distributed within the disks around young stars.

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

In the image above the left-most panel shows the 1.3-millimeter dust continuum images of five complex circumstellar disks. The panels to the right show gas measurements for each disk in different velocity channels, revealing “velocity kinks” — deviations from the normal Keplerian velocity expected from unperturbed, orbiting gas. According to Pinte and collaborators, the kinks signatures of planets that perturb the gas flow in their vicinity. For more information, check out the article below.

Citation

“Nine Localized Deviations from Keplerian Rotation in the DSHARP Circumstellar Disks: Kinematic Evidence for Protoplanets Carving the Gaps,” C. Pinte et al 2020 ApJL 890 L9.

https://iopscience.iop.org/article/10.3847/2041-8213/ab6dda

See the full article here .

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AAS Mission and Vision Statement

The mission of the American Astronomical Society is to enhance and share humanity’s scientific understanding of the Universe.

The Society, through its publications, disseminates and archives the results of astronomical research. The Society also communicates and explains our understanding of the universe to the public.
The Society facilitates and strengthens the interactions among members through professional meetings and other means. The Society supports member divisions representing specialized research and astronomical interests.
The Society represents the goals of its community of members to the nation and the world. The Society also works with other scientific and educational societies to promote the advancement of science.
The Society, through its members, trains, mentors and supports the next generation of astronomers. The Society supports and promotes increased participation of historically underrepresented groups in astronomy.
The Society assists its members to develop their skills in the fields of education and public outreach at all levels. The Society promotes broad interest in astronomy, which enhances science literacy and leads many to careers in science and engineering.

Adopted June 7, 2009

From ALMA: “The Strange Orbits of ‘Tatooine’ Planetary Disks”

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

From ALMA

Ian Czekala
University of California at Berkeley
Phone: +1 (631) 793 9292
Email: iczekala@berkeley.edu

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

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

Bárbara Ferreira
ESO Public Information Officer
Garching bei München, Germany
Phone: +49 89 3200 6670
Email: pio@eso.org

Iris Nijman
Public Information Officer
National Radio Astronomy Observatory Charlottesville, Virginia – USA
Cell phone: +1 (434) 249 3423
Email: alma-pr@nrao.edu

Two examples of aligned and misaligned protoplanetary disks around binary stars (circumbinary disks), observed with ALMA. Binary star orbits are added for clarity. Left: in star system HD 98800 B, the disk is misaligned with inner binary stars. The stars are orbiting each other (in this view, towards and away from us) in 315 days. Right: in star system AK Sco, the disk is in line with the orbit of its binary stars. The stars are orbiting each other in 13.6 days. Credit: ALMA (ESO/NAOJ/NRAO), I. Czekala and G. Kennedy; NRAO/AUI/NSF, S. Dagnello.

Artist impression of a double sunset on a ‘Tatooine’ exoplanet forming in a circumbinary disk that is misaligned with the orbits of its binary stars. Credit: NRAO/AUI/NSF, S. Dagnello.

Astronomers using the Atacama Large Millimeter/submillimeter Array (ALMA) have found striking orbital geometries in protoplanetary disks around binary stars. While disks orbiting the most compact binary star systems share very nearly the same plane, disks encircling wide binaries have orbital planes that are severely tilted. These systems can teach us about planet formation in complex environments.

In the last two decades, thousands of planets have been found orbiting stars other than our Sun. Some of these planets orbit two stars, just like Luke Skywalker’s home Tatooine. Planets are born in protoplanetary disks – we now have wonderful observations of these thanks to ALMA – but most of the disks studied so far orbit single stars. ‘Tatooine’ exoplanets form in disks around binary stars, so-called circumbinary disks.

Studying the birthplaces of ‘Tatooine’ planets provides a unique opportunity to learn about how planets form in different environments. Astronomers already know that the orbits of binary stars can warp and tilt the disk around them, resulting in a circumbinary disk misaligned relative to the orbital plane of its host stars. For example, in a 2019 study led by Grant Kennedy of the University of Warwick, UK [Nature Astronomy], ALMA found a striking circumbinary disk in a polar configuration.

“With our study, we wanted to learn more about the typical geometries of circumbinary disks,” said astronomer Ian Czekala of the University of California at Berkeley. Czekala and his team used ALMA data to determine the degree of alignment of nineteen protoplanetary disks around binary stars. “The high resolution ALMA data was critical for studying some of the smallest and faintest circumbinary disks yet,” said Czekala.

The astronomers compared the ALMA data of the circumbinary disks with the dozen ‘Tatooine’ planets that have been found with the Kepler space telescope. To their surprise, the team found that the degree to which binary stars and their circumbinary disks are misaligned is strongly dependent on the orbital period of the host stars. The shorter the orbital period of the binary star, the more likely it is to host a disk in line with its orbit. However, binaries with periods longer than a month typically host misaligned disks.

“We see a clear overlap between the small disks, orbiting compact binaries, and the circumbinary planets found with the Kepler mission,” Czekala said. Because the primary Kepler mission lasted 4 years, astronomers were only able to discover planets around binary stars that orbit each other in fewer than 40 days. And all of these planets were aligned with their host star orbits. A lingering mystery was whether there might be many misaligned planets that Kepler would have a hard time finding. “With our study, we now know that there likely isn’t a large population of misaligned planets that Kepler missed, since circumbinary disks around tight binary stars are also typically aligned with their stellar hosts,” added Czekala.

Still, based on this finding, the astronomers conclude that misaligned planets around wide binary stars should be out there and that it would be an exciting population to search for with other exoplanet-finding methods like direct imaging and microlensing.

Direct imaging-This false-color composite image traces the motion of the planet Fomalhaut b, a world captured by direct imaging. Credit: NASA, ESA, and P. Kalas (University of California, Berkeley and SETI Institute

Gravitational microlensing, S. Liebes, Physical Review B, 133 (1964): 835

(NASA’s Kepler mission used the transit method, which is one of the ways to find a planet.)

Planet transit. NASA/Ames.

Czekala now wants to find out why there is such a strong correlation between disk (mis)alignment and the binary star orbital period. “We want to use existing and coming facilities like ALMA and the next generation Very Large Array to study disk structures at exquisite levels of precision,” he said, “and try to understand how warped or tilted disks affect the planet formation environment and how this might influence the population of planets that form within these disks.”

“This research is a great example of how new discoveries build on previous observations,” said Joe Pesce, National Science Foundation Program Officer for NRAO and ALMA. “Discerning trends in the circumbinary disk population was only made possible by building on the foundation of archival observational programs undertaken by the ALMA community in previous cycles.”

The astronomers published their results in The Astrophysical Journal.

See the full article here .

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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 Spots Metamorphosing Aged Star”

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

From ALMA

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

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

Bárbara Ferreira
ESO Public Information Officer
Garching bei München, Germany
Phone: +49 89 3200 6670
Email: pio@eso.org

Iris Nijman
Public Information Officer
National Radio Astronomy Observatory Charlottesville, Virginia – USA
Cell phone: +1 (434) 249 3423
Email: alma-pr@nrao.edu

ALMA image of the old star system W43A. The high velocity bipolar jets ejected from the central aged star are seen in blue, low velocity outflow is shown in green, and dusty clouds entrained by the jets are shown in orange.
Credit: ALMA (ESO/NAOJ/NRAO), Tafoya et al.

Artist’s impression of W43A based on the ALMA observation results. Diffuse spherical gas was emitted from the star in the past. W43A has just started ejecting bipolar jets which entrain the surrounding material. Bright spots in radio emissions from water molecules are distributed around the interface of the jets and the diffuse gas.
Credit: NAOJ.

An international team of astronomers using the Atacama Large Millimeter/submillimeter Array (ALMA) captured the very moment when an old star first starts to alter its environment. The star has ejected high-speed bipolar gas jets which are now colliding with the surrounding material; the age of the observed jet is estimated to be less than 60 years. These are key features to understand how the complex shapes of planetary nebulae are formed.
Sun-like stars evolve to puffed-up Red Giants in the final stage of their lives. Then, the star expels gas to form a remnant called a planetary nebula. There is a wide variety in the shapes of planetary nebulae; some are spherical, but others are bipolar or show complicated structures. Astronomers are interested in the origins of this variety, but the thick dust and gas expelled by an old star obscure the system and make it difficult to investigate the inner-workings of the process.

To tackle this problem, a team of astronomers led by Daniel Tafoya in Chalmers University of Technology, Sweden, pointed ALMA at W43A, an old star system in the constellation Aquila, the Eagle.

Thanks to ALMA’s high resolution, the team obtained a very detailed view of the space around W43A. “The most notable structures are its small bipolar jets,” says Tafoya, the lead author of the research paper published by the Astrophysical Journal Letters. The team found that the velocity of the jets is as high as 175 km per second, which is much higher than previous estimations. Based on this speed and the size of the jets, the team calculated the age of the jets to be less than a human life-span.

“Considering the youth of the jets compared to the overall lifetime of a star, it is safe to say we are witnessing the ‘exact moment’ that the jets have just started to shove through the surrounding gas,” explains Tafoya. “When the jets carve through the surrounding material in some 60 years, a single person can watch the progress in their life.”

In fact, the ALMA image clearly maps the distribution of dusty clouds entrained by the jets, which is telltale evidence that it is impacting on the surroundings.

The team assumes that this entrainment is the key to form a bipolar-shaped planetary nebula. In their scenario, the aged star originally ejects gas spherically and the core of the star loses its envelope. If the star has a companion, gas from the companion pours onto the core of the dying star, and a portion of this new gas forms the jets. Therefore, whether or not the old star has a companion is an important factor to determine the structure of the resulting planetary nebula.

“W43A is one of the peculiar so called ‘water fountain’ objects,” says Hiroshi Imai at Kagoshima University, Japan, a member of the team. “Some old stars show characteristic radio emissions from water molecules. We suppose that spots of these water emissions indicate the interface region between the jets and the surrounding material. We named them ‘water fountains,’ and it could be a sign that the central source is a binarity system launching a new jet.”

“There are only 15 ‘water fountain’ objects identified to date, despite the fact that more than 100 billion stars are included in our Milky Way Galaxy,” explains José Francisco Gómez at Instituto de Astrofísica de Andalucía, Spain. “This is probably because the lifetime of the jets is quite short, so we are very lucky to see such rare objects.”

Additional Information

These observation results were presented in D. Tafoya et al. “Shaping the envelope of the asymptotic giant branch star W43A with a collimated fast jet” published by The Astrophysical Journal Letters on February 13, 2020.

The research team members are Daniel Tafoya (Calmers University of Technology), Hiroshi Imai (Kagoshima University), José F. Gómez (Instituto de Astrofísica de Andalucía, CSIC), Jun-ichi Nakashima (Sun Yat-sen University), Gabor Orosz (University of Tasmania/Xinjiang Astronomical Observatory), and Bosco H. K. Yung (Nicolaus Copernicus Astronomical Center)

This research was supported by MEXT KAKENHI (No. 16H02167), the Invitation Program for Foreign Researchers of the Japan Society for Promotion of Science (JSPS grant S14128), MINECO (Spain) Grant AYA2017-84390-C2-R (co-funded by FEDER), State Agency for Research of the Spanish MCIU through the “Center of Excellence Severo Ochoa” award for the Instituto de Astrofisica de Andalucía (SEV-2017-0709), Australian Research Council Discovery project DP180101061 of the Australian government, CAS LCWR 2018-XBQNXZ-B-021, and National Key R&D Program 2018YFA0404602 of China.

See the full article here .

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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: “Galactic Cosmic Rays Affect Titan’s Atmosphere”

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

18 February, 2020

Valeria Foncea
Education and Public Outreach Officer
Joint ALMA Observatory Santiago – Chile
Phone: +56 2 2467 6258
Cell phone: +56 9 7587 1963
Email: valeria.foncea@alma.cl

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

Bárbara Ferreira
ESO Public Information Officer
Garching bei München, Germany
Phone: +49 89 3200 6670
Email: pio@eso.org

Iris Nijman
Public Information Officer
National Radio Astronomy Observatory Charlottesville, Virginia – USA
Cell phone: +1 (434) 249 3423
Email: alma-pr@nrao.edu

Optical image of Titan taken by NASA Cassini spacecraft. Credit: NASA/JPL-Caltech/Space Science Institute.

NASA/ESA/ASI Cassini-Huygens Spacecraft

ALMA spectra of CH3CN and CH3C15N Titan’s atmosphere. Dotted vertical lines indicate the frequency of emission lines of two molecules predicted by a theoretical model. Credit: Iino et al. (The University of Tokyo.)

Planetary scientists using the Atacama Large Millimeter/submillimeter Array (ALMA) revealed the secrets of the atmosphere of Titan, the largest moon of Saturn. The team found a chemical footprint in Titan’s atmosphere indicating that cosmic rays coming from outside the Solar System affect the chemical reactions involved in the formation of nitrogen-bearing organic molecules.

Cosmic rays produced by high-energy astrophysics sources (ASPERA collaboration – AStroParticle ERAnet)

This is the first observational confirmation of such processes, and impacts the understanding of the intriguing environment of Titan.

Titan is attracting much interest because of its unique atmosphere with a number of organic molecules that form a pre-biotic environment.

Takahiro Iino, a scientist at the University of Tokyo, and his team used ALMA to reveal the chemical processes in Titan’s atmosphere. They found faint but firm signals of acetonitrile (CH3CN) and its rare isotopomer CH3C15N in the ALMA data.

“We found that the abundance of 14N in acetonitrile is higher than those in other nitrogen bearing species such as HCN and HC3N,” says Iino. “It well matches the recent computer simulation of chemical processes with high energy cosmic rays.”

There are two important players in the chemical processes of the atmosphere: ultraviolet (UV) light from the Sun and cosmic rays coming from outside the Solar System. In the upper stratosphere, UV light selectively destroys nitrogen molecules containing 15N because UV light with the specific wavelength that interacts with 14N14N is neutralized at that altitude due to the strong absorption. Thus, nitrogen-bearing species produced at that altitude tend to exhibit a high 15N abundance. On the other hand, cosmic rays penetrate deeper and interact with nitrogen molecules containing only 14N. As a result, there is a difference in the abundance of molecules with 14N and 15N. The team revealed that acetonitrile in the lower stratosphere is more abundant in 14N than those of other previously measured nitrogen-bearing molecules.

“We suppose that galactic cosmic rays play an important role in the atmospheres of other solar system bodies,” says Hideo Sagawa, an associate professor at Kyoto Sangyo University and a member of the research team. “The process could be universal, so understanding the role of cosmic rays in Titan is crucial in overall planetary science.”

Titan is one of the most popular objects in ALMA observations. The data obtained with ALMA needs to be calibrated to remove fluctuations due to variations of on-site weather and mechanical glitches. For referencing, the observatory staff often points the telescope at bright sources, such as Titan, from time to time in science observations. Therefore, a large amount of Titan data is stored in the ALMA Science Archive. Iino and his team have dug into the archive and re-analyzed the Titan data and found subtle fingerprints of very tiny amounts of CH3C15N.

More information

These observation results are published as T. Iino et al. in The Astrophysical Journal.

The research team members are: Takahiro Iino (The University of Tokyo), Hideo Sagawa (Kyoto Sangyo University) and Takashi Tsukagoshi (National Astronomical Observatory of Japan).

This research was supported by the JSPS KAKENHI (No. 17K14420 and 19K14782), the Telecommunication Advancement Foundation, and the Astrobiology Center, National Institutes of Natural Sciences.

See the full article here .

five-ways-keep-your-child-safe-school-shootings

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: “How Newborn Stars Prepare for the Birth of Planets”

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

From ALMA

20 February, 2020

Valeria Foncea
Education and Public Outreach Officer
Joint ALMA Observatory Santiago – Chile
Phone: +56 2 2467 6258
Cell phone: +56 9 7587 1963
Email: valeria.foncea@alma.cl

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

Bárbara Ferreira
ESO Public Information Officer
Garching bei München, Germany
Phone: +49 89 3200 6670
Email: pio@eso.org

Iris Nijman
Public Information Officer
National Radio Astronomy Observatory Charlottesville, Virginia – USA
Cell phone: +1 (434) 249 3423
Email: alma-pr@nrao.edu

VANDAM survey
ALMA and the VLA observed more than 300 protostars and their young protoplanetary disks in Orion. This image shows a subset of stars, including a few binaries. The ALMA and VLA data compliment each other: ALMA sees the outer disk structure (visualized in blue), and the VLA observes the inner disks and star cores (orange).

NRAO/Karl V Jansky Expanded Very Large Array, on the Plains of San Agustin fifty miles west of Socorro, NM, USA, at an elevation of 6970 ft (2124 m)

An international team of astronomers used two of the most powerful radio telescopes in the world to create more than three hundred images of planet-forming disks around very young stars in the Orion Clouds. These images reveal new details about the birthplaces of planets and the earliest stages of star formation.

Most of the stars in the universe are accompanied by planets. These planets are born in rings of dust and gas, called protoplanetary disks. Even very young stars are surrounded by these disks. Astronomers want to know exactly when these disks start to form, and what they look like. But young stars are very faint, and there are dense clouds of dust and gas surrounding them in stellar nurseries. Only highly sensitive radio telescope arrays can spot the tiny disks around these infant stars amidst the densely packed material in these clouds.

For this new research, astronomers pointed both the Atacama Large Millimeter/submillimeter Array (ALMA) and the National Science Foundation’s Karl G. Jansky Very Large Array (VLA) to a region in space where many stars are born: the Orion Molecular Clouds. This survey, called VLA/ALMA Nascent Disk and Multiplicity (VANDAM), is the largest survey of young stars and their disks to date.

Very young stars, also called protostars, form in clouds of gas and dust in space. The first step in the formation of a star is when these dense clouds collapse due to gravity. As the cloud collapses, it begins to spin – forming a flattened disk around the protostar. Material from the disk continues to feed the star and make it grow. Eventually, the left-over material in the disk is expected to form planets.

Many aspects about these first stages of star formation, and how the disk forms, are still unclear. But this new survey provides some missing clues as the VLA and ALMA peered through the dense clouds and observed hundreds of protostars and their disks in various stages of their formation.

Young planet-forming disks

“This survey revealed the average mass and size of these very young protoplanetary disks,” said John Tobin of the National Radio Astronomy Observatory (NRAO) in Charlottesville, Virginia, and leader of the survey team. “We can now compare them to older disks that have been studied intensively with ALMA as well.”

What Tobin and his team found, is that very young disks can be similar in size, but are on average much more massive than older disks. “When a star grows, it eats away more and more material from the disk. This means that younger disks have a lot more raw material from which planets could form. Possibly bigger planets already start to form around very young stars.”

Four special protostars

Among hundreds of survey images, four protostars looked different than the rest and caught the scientists’ attention. “These newborn stars looked very irregular and blobby,” said team member Nicole Karnath of the University of Toledo, Ohio (now at SOFIA Science Center). “We think that they are in one of the earliest stages of star formation and some may not even have formed into protostars yet.”

It is special that the scientists found four of these objects. “We rarely find more than one such irregular object in one observation,” added Karnath, who used these four infant stars to propose a schematic pathway for the earliest stages of star formation. “We are not entirely sure how old they are, but they are probably younger than ten thousand years.”

To be defined as a typical (class 0) protostar, stars should not only have a flattened rotating disk surrounding them, but also an outflow – spewing away material in opposite directions – that clears the dense cloud surrounding the stars and makes them optically visible. This outflow is important, because it prevents stars from spinning out of control while they grow. But when exactly these outflows start to happen, is an open question in astronomy.

One of the infant stars in this study, called HOPS 404, has an outflow of only two kilometers (1.2 miles) per second (a typical protostar-outflow of 10-100 km/s or 6-62 miles/s). “It is a big puffy sun that is still gathering a lot of mass, but just started its outflow to lose angular momentum to be able to keep growing,” explained Karnath. “This is one of the smallest outflows that we have seen and it supports our theory of what the first step in forming a protostar looks like.”

Combining ALMA and VLA

The exquisite resolution and sensitivity provided by both ALMA and the VLA were crucial to understand both the outer and inner regions of protostars and their disks in this survey. While ALMA can examine the dense dusty material around protostars in great detail, the images from the VLA made at longer wavelengths were essential to understand the inner structures of the youngest protostars at scales smaller than our solar system.

“The combined use of ALMA and the VLA has given us the best of both worlds,” said Tobin. “Thanks to these telescopes, we start to understand how planet formation begins.”

The National Radio Astronomy Observatory is a facility of the National Science Foundation, operated under cooperative agreement by Associated Universities, Inc.

More Information

This research was presented in two papers:

The VLA/ALMA Nascent Disk and Multiplicity (VANDAM) Survey of Orion Protostars. A Statistical Characterization of Class 0 and I Protostellar Disks,” by J. Tobin et al., The Astrophysical Journal.

“Detection of Irregular, Sub-mm Opaque Structures in the Orion Molecular Clouds: Protostars within 10000 years of formation?,” by N. Karnath et al., The Astrophysical Journal.

Observed protostars in Orion Molecular Clouds
This image shows the Orion Molecular Clouds, the target of the VANDAM survey. Yellow dots are the locations of the observed protostars on a blue background image made by Herschel. Side panels show nine young protostars imaged by ALMA (blue) and the VLA (orange). Credit: ALMA (ESO/NAOJ/NRAO), J. Tobin; NRAO/AUI/NSF, S. Dagnello; Herschel/ESA

Schematic showing the formation of protostars
This schematic shows a proposed pathway (top row) for the formation of protostars, based on four very young protostars (bottom row) observed by VLA (orange) and ALMA (blue). Step 1 represents the collapsing fragment of gas and dust. In step 2, an opaque region starts to form in the cloud. In step 3, a hydrostatic core starts to form due to an increase in pressure and temperature, surrounded by a disk-like structure and the beginning of an outflow. Step 4 depicts the formation of a class 0 protostar inside the opaque region, that may have a rotationally supported disk and more well-defined outflows. Step 5 is a typical class 0 protostar with outflows that have broken through the envelope (making it optically visible), an actively accreting, rotationally supported disk. In the bottom row, white contours are the protostar outflows as seen with ALMA.
Credit: ALMA (ESO/NAOJ/NRAO), N. Karnath; NRAO/AUI/NSF, B. Saxton and S. Dagnello

Star chart of constellation Orion and observed protostars
The Orion Molecular Clouds (blue, as seen with Herschel) are located in the constellation Orion. Red dots show the locations of the observed protostars in the VANDAM survey.
Credit: IAU; Sky & Telescope magazine; NRAO/AUI/NSF, S. Dagnello; Herschel/ESA; ALMA (ESO/NAOJ/NRAO), J. Tobin

See the full article here .

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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 AAS NOVA: “ALMA Explores Possible Interacting Twin Disks”

From AAS NOVA

17 February 2020
Susanna Kohler

Artist’s impression of one of the two stars in the FU Orionis binary system, surrounded by an accreting disk of material. What has caused this star — and others like it — to dramatically brighten? [NASA/JPL-Caltech]

Some young stars seem to spend a brief portion of their lives undergoing dramatic, flaring outbursts. A new study has used the Atacama Large Millimeter/submillimeter Array (ALMA) in Chile to get the closest look yet at one of these systems — possibly identifying the cause of the flares.

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

Artist’s impression of a young star throwing a temper tantrum as it suddenly increases its accretion rate and flares. [Caltech/T. Pyle (IPAC)]

Young Stellar Temper Tantrums

FU Orionis (FU Ori, for short) objects are young, pre-main-sequence stars that grow suddenly brighter — by several magnitudes! — over the span of perhaps a year. These flaring states can last on the order of decades, and they’re thought to be related to a period of increased accretion onto the star during its early years. A star may gain a significant portion of its final mass during these events.

Beyond this general picture, there’s much we don’t understand about how or why this increase in accretion occurs. Does every star undergo a FU Ori phase early in its lifetime, accumulating extra mass in spurts and brightening each time it does? Or do only some stars behave this way? What causes the change in accretion rate? What ends this phase?

The first step to answering some of these questions is to obtain high-resolution images of FU Ori objects so that we can better explore their structure and behavior. In a new study, a team of scientists led by Sebastián Pérez (University of Santiago, Chile; University of Chile) has used ALMA to capture a detailed look at the archetypal FU Ori system for which these objects were named.

Signs of Interaction

ALMA continuum observations show the dust of the two disks surrounding the binary stars of FU Orionis. Each disk is about 11 AU in radius. [Pérez et al. 2020]

FU Orionis is a binary pair of young stars that lies roughly 1,360 light-years away in the constellation of Orion. Pérez and collaborators’ ALMA observations of the system resolved, for the first time, the disks of accreting dust surrounding each of the young stars. Modeling of these disks allowed the authors to infer that they are roughly 11 AU in radius and their separation is perhaps 250 AU.

Observations of the gas in the disks reveal its kinematics, demonstrating that the rotation of each disk is somewhat asymmetric and skewed. The authors propose that this indicates some sort of close encounter for the disks — perhaps the flyby of another star within this crowded star-forming region, or possibly even the direct interaction of the two disks of the binary with each other.

An elongated arc of gas may connect the two components, further strengthening the argument that the two disks are interacting. And close passes between the disks of a binary or perturbations from a flyby could easily increase the accretion rate onto the stars, fueling the FU Ori outburst that we now observe.

Several other FU Ori systems are in known binaries, providing additional targets that we can follow up with to test whether disk interactions can truly explain these objects’ sudden, dramatic flares. Meanwhile, ALMA continues to play an important role in helping us to explore how stars form and evolve.

Citation

“Resolving the FU Orionis System with ALMA: Interacting Twin Disks?,” Sebastián Pérez et al 2020 ApJ 889 59.
https://iopscience.iop.org/article/10.3847/1538-4357/ab5c1b

See the full article here .

five-ways-keep-your-child-safe-school-shootings

Please help promote STEM in your local schools.

Stem Education Coalition

AAS Mission and Vision Statement

The mission of the American Astronomical Society is to enhance and share humanity’s scientific understanding of the Universe.

The Society, through its publications, disseminates and archives the results of astronomical research. The Society also communicates and explains our understanding of the universe to the public.
The Society facilitates and strengthens the interactions among members through professional meetings and other means. The Society supports member divisions representing specialized research and astronomical interests.
The Society represents the goals of its community of members to the nation and the world. The Society also works with other scientific and educational societies to promote the advancement of science.
The Society, through its members, trains, mentors and supports the next generation of astronomers. The Society supports and promotes increased participation of historically underrepresented groups in astronomy.
The Society assists its members to develop their skills in the fields of education and public outreach at all levels. The Society promotes broad interest in astronomy, which enhances science literacy and leads many to careers in science and engineering.

Adopted June 7, 2009

From ALMA:”Galactic Cosmic Rays Affect Titan’s Atmosphere”

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

From ALMA

2020.02.14

Planetary scientists using the Atacama Large Millimeter/submillimeter Array (ALMA) revealed the secrets of the atmosphere of Titan, the largest moon of Saturn. The team found a chemical footprint in Titan’s atmosphere indicating that cosmic rays coming from outside the Solar System affect the chemical reactions involved in the formation of nitrogen-bearing organic molecules. This is the first observational confirmation of such processes, and impacts the understanding of the intriguing environment of Titan.

Optical image of Titan taken by NASA Cassini spacecraft. Credit: NASA/JPL-Caltech/Space Science Institute

NASA/ESA/ASI Cassini-Huygens Spacecraft

Titan is attracting much interest because of its unique atmosphere with a number of organic molecules that form a pre-biotic environment.

Takahiro Iino, a scientist at the University of Tokyo, and his team used ALMA to reveal the chemical processes in Titan’s atmosphere. They found faint but firm signals of acetonitrile (CH3CN) and its rare isotopomer CH3C^15N in the ALMA data.

ALMA spectra of CH3CN and CH3C^15N Titan’s atmosphere. Dotted vertical lines indicate the frequency of emission lines of two molecules predicted by a theoretical model.
Credit: Iino et al. (The University of Tokyo)

“We found that the abundance of 14N in acetonitrile is higher than those in other nitrogen bearing species such as HCN and HC3N,” says Iino. “It well matches the recent computer simulation of chemical processes with high energy cosmic rays.”

There are two important players in the chemical processes of the atmosphere;
ultraviolet (UV) light from the Sun and cosmic rays coming from outside the Solar System. In the upper atmosphere, UV light selectively destroys nitrogen molecules containing 15N because the UV light with the specific wavelength that interacts with 14N14N is easily absorbed at that altitude. Thus, nitrogen-bearing species produced at that altitude tend to exhibit a high 15N abundance. On the other hand, cosmic rays penetrate deeper and interact with nitrogen molecules containing 14N. As a result, there is a difference in the abundance of molecules with 14N and 15N. The team revealed that acetonitrile in the stratosphere is more abundant in 14N than those of other previously measured nitrogen-bearing molecules.

“We suppose that galactic cosmic rays play an important role in the atmospheres of other solar system bodies,” says Hideo Sagawa, an associate professor at Kyoto Sangyo University and a member of the research team. “The process could be universal, so understanding the role of cosmic rays in Titan is crucial in overall planetary science.”

Titan is one of the most popular objects in ALMA observations. The data obtained with ALMA needs to be calibrated to remove fluctuations due to variations of on-site weather and mechanical glitches. For referencing, the observatory staff often points the telescope at bright sources, such as Titan, from time to time in science observations. Therefore, a large amount of Titan data is stored in the ALMA Science Archive. Iino and his team have dug into the archive and re-analyzed the Titan data and found subtle fingerprints of very tiny amounts of CH3C15N.

Paper and the research team
These observation results are published as T. Iino et al. “14N/15N isotopic ratio in CH3CN of Titan’s atmosphere measured with ALMA” in The Astrophysical Journal published on February 2019.

The research team members are:
Takahiro Iino (The University of Tokyo), Hideo Sagawa (Kyoto Sangyo University) and Takashi Tsukagoshi (National Astronomical Observatory of Japan).

This research was supported by the JSPS KAKENHI (No. 17K14420 and 19K14782), the Telecommunication Advancement Foundation, and the Astrobiology Center, National Institutes of Natural Sciences.

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.