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  • richardmitnick 8:54 pm on May 23, 2022 Permalink | Reply
    Tags: "Planets of binary stars as possible homes for alien life", , , Bursts may influence the structure of the later planetary system., , , , , Planetary research, , The binary star systems studied in this work-NGC 1333-IRAS2A-is surrounded by a disc consisting of gas and dust., , The team has complemented the observations with computer simulations reaching both backwards and forwards in time., The two stars encircle each other and at given intervals their joint gravity will affect the surrounding gas and dust disc in a way which causes huge amounts of material to fall towards the star.   

    From The Niels Bohr Institute [Niels Bohr Institutet] (DK): “Planets of binary stars as possible homes for alien life” 

    Niels Bohr Institute bloc

    From The Niels Bohr Institute [Niels Bohr Institutet] (DK)

    at

    University of Copenhagen [Københavns Universitet] [UCPH] (DK)

    23 May 2022

    Contacts:

    Jes Kristian Jørgensen
    Professor
    Astrophysics and Planetary Science
    Niels Bohr Institute
    University of Copenhagen
    jeskj@nbi.ku.dk
    +45 35 32 41 86

    Rajika L. Kuruwita
    Postdoc
    Astrophysics and Planetary Science
    Niels Bohr Institute
    University of Copenhagen
    rajika.kuruwita@nbi.ku.dk
    +45 35 32 79 98

    Maria Hornbek
    Journalist
    Faculty of Science
    University of Copenhagen
    maho@science.ku.dk
    +45 22 95 42 83

    Nearly half of Sun-size stars are binary. According to University of Copenhagen research, planetary systems around binary stars may be very different from those around single stars. This points to new targets in the search for extraterrestrial life forms.

    Since the only known planet with life, the Earth, orbits the Sun, planetary systems around stars of similar size are obvious targets for astronomers trying to locate extraterrestrial life. Nearly every second star in that category is a binary star. A new result from research at University of Copenhagen indicate that planetary systems are formed in a very different way around binary stars than around single stars such as the Sun.

    “The result is exciting since the search for extraterrestrial life will be equipped with several new, extremely powerful instruments within the coming years. This enhances the significance of understanding how planets are formed around different types of stars. Such results may pinpoint places which would be especially interesting to probe for the existence of life,” says Professor Jes Kristian Jørgensen, Niels Bohr Institute, University of Copenhagen, heading the project.

    The results from the project, which also has participation of astronomers from Taiwan and USA, are published in the distinguished journal Nature.

    Bursts shape the planetary system

    The new discovery has been made based on observations made by the ALMA telescopes in Chile of a young binary star about 1,000 lightyears from Earth.

    The binary star system, NGC 1333-IRAS2A, is surrounded by a disc consisting of gas and dust. The observations can only provide researchers with a snapshot from a point in the evolution of the binary star system. However, the team has complemented the observations with computer simulations reaching both backwards and forwards in time.

    “The observations allow us to zoom in on the stars and study how dust and gas move towards the disc. The simulations will tell us which physics are at play, and how the stars have evolved up till the snapshot we observe, and their future evolution,” explains Postdoc Rajika L. Kuruwita, Niels Bohr Institute, second author of the Nature article.

    2
    Simulation of binary star (from the scientific article by Jørgensen, Kuruwita et al.)

    Notably, the movement of gas and dust does not follow a continuous pattern. At some points in time – typically for relatively shorts periods of ten to one hundred years every thousand years – the movement becomes very strong. The binary star becomes ten to one hundred times brighter, until it returns to its regular state.

    Presumably, the cyclic pattern can be explained by the duality of the binary star. The two stars encircle each other, and at given intervals their joint gravity will affect the surrounding gas and dust disc in a way which causes huge amounts of material to fall towards the star.

    “The falling material will trigger a significant heating. The heat will make the star much brighter than usual,” says Rajika L. Kuruwita, adding:

    “These bursts will tear the gas and dust disc apart. While the disc will build up again, the bursts may still influence the structure of the later planetary system.”

    Comets carry building blocks for life.

    The observed stellar system is still too young for planets to have formed. The team hopes to obtain more observational time at ALMA, allowing to investigate the formation of planetary systems.

    Not only planets but also comets will be in focus:

    “Comets are likely to play a key role in creating possibilities for life to evolve. Comets often have a high content of ice with presence of organic molecules. It can well be imagined that the organic molecules are preserved in comets during epochs where a planet is barren, and that later comet impacts will introduce the molecules to the planet’s surface,” says Jes Kristian Jørgensen.

    Understanding the role of the bursts is important in this context:

    “The heating caused by the bursts will trigger evaporation of dust grains and the ice surrounding them. This may alter the chemical composition of the material from which planets are formed.”

    Thus, chemistry is a part of the research scope:

    “The wavelengths covered by ALMA allow us to see quite complex organic molecules, so molecules with 9-12 atoms and containing carbon. Such molecules can be building blocks for more complex molecules which are key to life as we know it. For example, amino acids which have been found in comets.”

    Powerful tools join the search for life in space

    ALMA (Atacama Large Millimeter/submillimeter Array) is not a single instrument but 66 telescopes operating in coordination. This allows for a much better resolution than could have been obtained by a single telescope.

    Very soon the new James Webb Space Telescope (JWST) will join the search for extraterrestrial life.

    Near the end of the decade, JWST will be complemented by the ELT (European Large Telescope) and the extremely powerful SKA (Square Kilometer Array) both planned to begin observing in 2027.

    The ELT will with its 39-meter mirror be the biggest optical telescope in the world and will be poised to observe the atmospheric conditions of exoplanets (planets outside the Solar System, ed.). SKA will consist of thousands of telescopes in South Africa and in Australia working in coordination and will have longer wavelengths than ALMA.

    ”The SKA will allow for observing large organic molecules directly. The James Webb Space Telescope operates in the infrared which is especially well suited for observing molecules in ice. Finally, we continue to have ALMA which is especially well suited for observing molecules in gas form. Combining the different sources will provide a wealth of exciting results,” Jes Kristian Jørgensen concludes.

    See the full article here .


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    Stem Education Coalition

    Niels Bohr Institute Campus

    The Niels Bohr Institutet (DK) is a research institute of the Københavns Universitet [UCPH] (DK). The research of the institute spans astronomy, geophysics, nanotechnology, particle physics, quantum mechanics and biophysics.

    The Institute was founded in 1921, as the Institute for Theoretical Physics of the Københavns Universitet [UCPH] (DK), by the Danish theoretical physicist Niels Bohr, who had been on the staff of the University of Copenhagen since 1914, and who had been lobbying for its creation since his appointment as professor in 1916. On the 80th anniversary of Niels Bohr’s birth – October 7, 1965 – the Institute officially became The Niels Bohr Institutet (DK). Much of its original funding came from the charitable foundation of the Carlsberg brewery, and later from the Rockefeller Foundation.

    During the 1920s, and 1930s, the Institute was the centre of the developing disciplines of atomic physics and quantum physics. Physicists from across Europe (and sometimes further abroad) often visited the Institute to confer with Bohr on new theories and discoveries. The Copenhagen interpretation of quantum mechanics is named after work done at the Institute during this time.

    On January 1, 1993 the institute was fused with the Astronomic Observatory, the Ørsted Laboratory and the Geophysical Institute. The new resulting institute retained the name Niels Bohr Institutet (DK).

    Københavns Universitet (UCPH) (DK) is the oldest university and research institution in Denmark. Founded in 1479 as a studium generale, it is the second oldest institution for higher education in Scandinavia after Uppsala University (1477). The university has 23,473 undergraduate students, 17,398 postgraduate students, 2,968 doctoral students and over 9,000 employees. The university has four campuses located in and around Copenhagen, with the headquarters located in central Copenhagen. Most courses are taught in Danish; however, many courses are also offered in English and a few in German. The university has several thousands of foreign students, about half of whom come from Nordic countries.

    The university is a member of the International Alliance of Research Universities (IARU), along with University of Cambridge (UK), Yale University , The Australian National University (AU), and University of California-Berkeley , amongst others. The 2016 Academic Ranking of World Universities ranks the University of Copenhagen as the best university in Scandinavia and 30th in the world, the 2016-2017 Times Higher Education World University Rankings as 120th in the world, and the 2016-2017 QS World University Rankings as 68th in the world. The university has had 9 alumni become Nobel laureates and has produced one Turing Award recipient.

     
  • richardmitnick 5:33 pm on February 22, 2021 Permalink | Reply
    Tags: "SwRI scientists image a bright meteoroid explosion in Jupiter’s atmosphere", A large meteoroid exploded in a bright fireball in Jupiter's upper atmosphere., , , , Comet Shoemaker Levy 9 was still responsible for 95% of the stratospheric water on Jupiter 15 years after the impact., Comet Shoemaker-Levy was the largest observed Jupiter impactor., , Planetary research, , The Ultraviolet Spectrograph (UVS) on Juno spacecraft., Transient Luminous Events (TLEs) are upper atmospheric phenomenon triggered by lightning lasting milliseconds.   

    From Southwest Research Institute: “SwRI scientists image a bright meteoroid explosion in Jupiter’s atmosphere” 

    SwRI bloc

    From Southwest Research Institute

    February 22, 2021

    From aboard the Juno spacecraft, a Southwest Research Institute-led instrument observing auroras serendipitously spotted a bright flash above Jupiter’s clouds last spring. The Ultraviolet Spectrograph (UVS) team studied the data and determined that they had captured a bolide, an extremely bright meteoroid explosion in the gas giant’s upper atmosphere.

    NASA/Juno at Jupiter.

    1
    SwRI scientists studied the area imaged by Juno’s UVS instrument on April 10, 2020, and determined that a large meteoroid had exploded in a bright fireball in Jupiter’s upper atmosphere.

    2
    The Ultraviolet Spectrograph (UVS) on Juno spacecraft. Credit: NASA.

    The UVS swath includes a segment of Jupiter’s northern auroral oval, appearing purely in green, representing hydrogen emissions. In contrast, the bright spot (see enlargement) appears mostly yellow, indicating significant emissions at longer wavelengths. Credit: SwRI.

    “Jupiter undergoes a huge number of impacts per year, much more than the Earth, so impacts themselves are not rare,” said SwRI’s Dr. Rohini Giles, lead author of a paper outlining these findings in Geophysical Research Letters. “However, they are so short-lived that it is relatively unusual to see them. Only larger impacts can be seen from Earth, and you have to be lucky to be pointing a telescope at Jupiter at exactly the right time. In the last decade, amateur astronomers have managed to capture six impacts on Jupiter.”

    Since Juno arrived at Jupiter in 2016, UVS has been used to study the morphology, brightness and spectral characteristics of Jupiter’s auroras as the spacecraft cartwheels close to its surface every 53 days. During the course of a 30-second spin, UVS observes a swath of the planet. The UVS instrument has occasionally observed short-lived, localized ultraviolet emissions outside of the auroral zone, including a singular event on April 10, 2020.

    “This observation is from a tiny snapshot in time — Juno is a spinning spacecraft, and our instrument observed that point on the planet for just 17 milliseconds, and we don’t know what happened to the bright flash outside of that time frame,” Giles said, “But we do know that we didn’t see it on an earlier spin or a later spin, so it must have been pretty short-lived.”

    Previously, UVS had observed a set of eleven bright transient flashes that lasted 1 to 2 milliseconds. They were identified as Transient Luminous Events (TLEs), an upper atmospheric phenomenon triggered by lightning. The team initially thought this bright flash might be a TLE, however, it was different in two key ways. While it was also short-lived, it lasted at least 17 milliseconds, much longer than a TLE. It also had very different spectral characteristics. Spectra of TLEs and auroras feature emissions of molecular hydrogen, the main component of Jupiter’s atmosphere. This bolide event had a smooth “blackbody’’ curve, which is what is expected from a meteor.

    “The flash duration and spectral shape match up well with what we expect from an impact,” Giles said. “This bright flash stood out in the data, as it had very different spectral characteristics than the UV emissions from the Jupiter’s auroras. From the UV spectrum, we can see that the emission came from blackbody with a temperature of 9600 Kelvin, located at an altitude of 140 miles above the planet’s cloud tops. By looking at the brightness of the bright flash, we estimate that it was caused by an impactor with a mass of 550–3,300 pounds.”

    Comet Shoemaker-Levy was the largest observed Jupiter impactor. The comet broke apart in July 1992 and collided with Jupiter in July 1994, which was closely observed by astronomers worldwide and the Galileo spacecraft.

    ESA Galileo Spacecraft

    An SwRI-led team detected impact-related X-ray emissions from Jupiter’s northern hemisphere, and prominent scars from the impacts persisted for many months.

    “Impacts from asteroids and comets can have a significant impact on the planet’s stratospheric chemistry — 15 years after the impact, comet Shoemaker Levy 9 was still responsible for 95% of the stratospheric water on Jupiter,” Giles said. “Continuing to observe impacts and estimating the overall impact rates is therefore an important element of understanding the planet’s composition.”

    The Jet Propulsion Laboratory, a division of Caltech in Pasadena, California, manages the Juno mission for the principal investigator, Dr. Scott J. Bolton, of Southwest Research Institute. Juno is part of NASA’s New Frontiers Program, which is managed at NASA’s Marshall Space Flight Center in Huntsville, Alabama, for the agency’s Science Mission Directorate in Washington. Lockheed Martin Space in Denver built and operates the spacecraft.

    See the full article here .

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    Please help promote STEM in your local schools.

    Stem Education Coalition

    SwRI Campus

    Southwest Research Institute (SwRI) is an independent, nonprofit applied research and development organization. The staff of nearly 2,800 specializes in the creation and transfer of technology in engineering and the physical sciences. SwRI’s technical divisions offer a wide range of technical expertise and services in such areas as engine design and development, emissions certification testing, fuels and lubricants evaluation, chemistry, space science, nondestructive evaluation, automation, mechanical engineering, electronics, and more.

     
  • richardmitnick 10:11 am on November 19, 2020 Permalink | Reply
    Tags: "Stanford researchers model source of eruption on Jupiter’s moon Europa", , , , , Planetary research,   

    From Stanford University: “Stanford researchers model source of eruption on Jupiter’s moon Europa” 

    Stanford University Name
    From Stanford University

    November 10, 2020
    Danielle Torrent Tucker

    A new model shows how brine on Jupiter’s moon Europa can migrate within the icy shell to form pockets of salty water that erupt to the surface when freezing. The findings, which are important for the upcoming Europa Clipper mission, may explain cryovolcanic eruptions across icy bodies in the solar system.

    NASA/Europa Clipper annotated.

    NASA Europa Clipper depiction

    On Jupiter’s icy moon Europa, powerful eruptions may spew into space, raising questions among hopeful astrobiologists on Earth: What would blast out from miles-high plumes? Could they contain signs of extraterrestrial life? And where in Europa would they originate? A new explanation now points to a source closer to the frozen surface than might be expected.

    1
    This artist’s conception of Jupiter’s icy moon Europa shows a hypothesized cryovolcanic eruption, in which briny water from within the icy shell blasts into space. A new model of this process on Europa may also explain plumes on other icy bodies. Credit: Justice Blaine Wainwright.

    Rather than originating from deep within Europa’s oceans, some eruptions may originate from water pockets embedded in the icy shell itself, according to new evidence from researchers at Stanford University, the University of Arizona, the University of Texas and NASA’s Jet Propulsion Laboratory.

    Using images collected by the NASA spacecraft Galileo, the researchers developed a model to explain how a combination of freezing and pressurization could lead to a cryovolcanic eruption, or a burst of water.

    NASA/Galileo 1989-2003

    The results, published Nov. 10 in Geophysical Research Letters, have implications for the habitability of Europa’s underlying ocean – and may explain eruptions on other icy bodies in the solar system.

    Harbingers of life?

    Scientists have speculated that the vast ocean hidden beneath Europa’s icy crust could contain elements necessary to support life. But short of sending a submersible to the moon to explore, it’s difficult to know for sure. That’s one reason Europa’s plumes have garnered so much interest: If the eruptions are coming from the subsurface ocean, the elements could be more easily detected by a spacecraft like the one planned for NASA’s upcoming Europa Clipper mission [above].

    But if the plumes originate in the moon’s icy shell, they may be less hospitable to life, because it is more difficult to sustain the chemical energy to power life there. In this case, the chances of detecting habitability from space are diminished.

    “Understanding where these water plumes are coming from is very important for knowing whether future Europa explorers could have a chance to actually detect life from space without probing Europa’s ocean,” said lead author Gregor Steinbrügge, a postdoctoral researcher at Stanford’s School of Earth, Energy & Environmental Sciences (Stanford Earth).

    The researchers focused their analyses on Manannán, an 18-mile-wide crater on Europa that was created by an impact with another celestial object some tens of millions of years ago. Reasoning that such a collision would have generated a tremendous amount of heat, they modeled how melting and subsequent freezing of a water pocket within the icy shell could have caused the water to erupt.

    “The comet or asteroid hitting the ice shell was basically a big experiment which we’re using to construct hypotheses to test,” said co-author Don Blankenship, senior research scientist at the University of Texas Institute for Geophysics (UTIG) and principal investigator of the Radar for Europa Assessment and Sounding: Ocean to Near-surface (REASON) instrument that will fly on Europa Clipper. “The polar and planetary sciences team at UTIG are all currently dedicated to evaluating the ability of this instrument to test those hypotheses.”

    The model indicates that as Europa’s water transformed into ice during the later stages of the impact, pockets of water with increased salinity could be created in the moon’s surface. Furthermore, these salty water pockets can migrate sideways through Europa’s ice shell by melting adjacent regions of less brackish ice, and consequently become even saltier in the process.

    “We developed a way that a water pocket can move laterally – and that’s very important,” Steinbrügge said. “It can move along thermal gradients, from cold to warm, and not only in the down direction as pulled by gravity.”

    A salty driver

    The model predicts that when a migrating brine pocket reached the center of Manannán crater, it became stuck and began freezing, generating pressure that eventually resulted in a plume, estimated to have been over a mile high. The eruption of this plume left a distinguishing mark: a spider-shaped feature on Europa’s surface that was observed by Galileo imaging and incorporated in the researchers’ model.

    “Even though plumes generated by brine pocket migration would not provide direct insight into Europa’s ocean, our findings suggest that Europa’s ice shell itself is very dynamic,” said co-lead author Joana Voigt, a graduate research assistant at the University of Arizona, Tucson.

    The relatively small size of the plume that would form at Manannán indicates that impact craters probably can’t explain the source of other, larger plumes on Europa that have been hypothesized based on Hubble and Galileo data, the researchers say. But the process modeled for the Manannán eruption could happen on other icy bodies – even without an impact event.

    “Brine pocket migration is not uniquely applicable to Europan craters,” Voigt said. “Instead the mechanism might provide explanations on other icy bodies where thermal gradients exist.”

    The study also provides estimates of how salty Europa’s frozen surface and ocean may be, which in turn could affect the transparency of its ice shell to radar waves. The calculations, based on imaging from Galileo from 1995 to 1997, show Europa’s ocean may be about one-fifth as salty as Earth’s ocean – a factor that will improve the capacity for the Europa Clipper mission’s radar sounder to collect data from its interior.

    The findings may be discouraging to astrobiologists hoping Europa’s erupting plumes might contain clues about the internal ocean’s capacity to support life, given the implication that plumes do not have to connect to Europa’s ocean. However, the new model offers insights toward untangling Europa’s complex surface features, which are subject to hydrological processes, the pull of Jupiter’s gravity and hidden tectonic forces within the icy moon.

    “This makes the shallow subsurface – the ice shell itself – a much more exciting place to think about,” said co-author Dustin Schroeder, an assistant professor of geophysics at Stanford. “It opens up a whole new way of thinking about what’s happening with water near the surface.”

    See the full article here .


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    Please help promote STEM in your local schools.

    Stem Education Coalition

    Stanford University campus. No image credit

    Stanford University

    Leland and Jane Stanford founded the University to “promote the public welfare by exercising an influence on behalf of humanity and civilization.” Stanford opened its doors in 1891, and more than a century later, it remains dedicated to finding solutions to the great challenges of the day and to preparing our students for leadership in today’s complex world. Stanford, is an American private research university located in Stanford, California on an 8,180-acre (3,310 ha) campus near Palo Alto. Since 1952, more than 54 Stanford faculty, staff, and alumni have won the Nobel Prize, including 19 current faculty members

    Stanford University Seal

     
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