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  • Amateur astronomer's data helps scientists discover a new exoplanet
    Freitag, 18.05.2018, 03:46:05 Uhr
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    Amateur astronomer's data helps scientists discover a new exoplanet Yekaterinburg, Russia (SPX) May 18, 2018 -
    One of the candidates previously found by the Kourovka Planet Search (KPS) project turned out to be the so-called hot Jupiter. The exoplanet, known as KPS-1b, orbits a star similar to the Sun with a period of 40 hours.The mass and size of the exoplanet KPS-1b are close to the characteristics of Jupiter, but it is located very close to its parent star. Due to such proximity to the star, the temperature of the atmosphere KPS-1b is much higher than that of Jupiter.Software for analyzing data and searching exoplanet candidates was developed in UrFU. Subsequent observations of exoplanets candidates were conducted in a number of observatories around the world including the Special Astrophysical Observatory of the Russian Academy of Sciences. Spectral observations, which allowed calculating the mass of the exoplanet, were conducted at Haute-Provence Observatory (France).According to the researchers, the current discovery is unique due to the fact that signs of exoplanet existence (exoplanetary transits) were found in the data gathered by an amateur astronomer using readily available and relatively affordable equipment.The discovery was made in collaboration with astronomers from Belgium, USA, England, France, the Netherlands, Turkey, Portugal, Lithuania, Italy and Canada.The search for new exoplanets, as well as detailed studies of already known extrasolar planets, allow scientists to come closer to understanding how our solar system was formed and evolved.Kourovka Planet Search (KPS) is a project of UrFU scientists, aimed at search for transit exoplanets. As part of this project, astronomers observed sites in the constellations Cygnus, Cassiopeia, and the Big Dipper.Research paper
  • Scientists crack how primordial life on Earth might have replicated itself
    Freitag, 18.05.2018, 03:46:05 Uhr
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    Scientists crack how primordial life on Earth might have replicated itself London, UK (SPX) May 16, 2018 -
    Scientists have created a new type of genetic replication system which demonstrates how the first life on Earth - in the form of RNA - could have replicated itself. The scientists from the Medical Research Council (MRC) Laboratory of Molecular Biology say the new RNA utilises a system of genetic replication unlike any known to naturally occur on Earth today.A popular theory for the earliest stages of life on Earth is that it was founded on strands of RNA, a chemical cousin of DNA. Like DNA, RNA strands can carry genetic information using a code of four molecular letters (bases), but RNA can be more than a simple 'string' of information. Some RNA strands can also fold up into three-dimensional shapes that can form enzymes, called ribozymes, and carry out chemical reactions.If a ribozyme could replicate folded RNA, it might be able to copy itself and support a simple living system.Previously, scientists had developed ribozymes that could replicate straight strands of RNA, but if the RNA was folded it blocked the ribozyme from copying it. Since ribozymes themselves are folded RNAs, their own replication is blocked.Now, in a paper published in the journal eLife, the scientists have resolved this paradox by engineering the first ribozyme that is able to replicate folded RNAs, including itself.Normally when copying RNA, an enzyme would add single bases (C, G, A or U) one at a time, but the new ribozyme uses three bases joined together, as a 'triplet' (e.g. GAU). These triplet building blocks enable the ribozyme to copy folded RNA, because the triplets bind to the RNA much more strongly and cause it to unravel - so the new ribozyme can copy its own folded RNA strands.The scientists say that the 'primordial soup' could have contained a mixture of bases in many lengths - one, two, three, four or more bases joined together - but they found that using strings of bases longer than a triplet made copying the RNA less accurate.Dr Philipp Holliger, from the MRC Laboratory of Molecular Biology and senior author on the paper, said: "We found a solution to the RNA replication paradox by re-thinking how to approach the problem - we stopped trying to mimic existing biology and designed a completely new synthetic strategy. It is exciting that our RNA can now synthesise itself."These triplets of bases seem to represent a sweet spot, where we get a nice opening up of the folded RNA structures, but accuracy is still high. Notably, although triplets are not used in present-day biology for replication, protein synthesis by the ribosome - an ancient RNA machine thought to be a relic of early RNA-based life - proceeds using a triplet code."However, this is only a first step because our ribozyme still needs a lot of help from us to do replication. We provided a pure system, so the next step is to integrate this into the more complex substrate mixtures mimicking the primordial soup - this likely was a diverse chemical environment also containing a range of simple peptides and lipids that could have interacted with the RNA."The experiments were conducted in ice at -7 C, because the researchers had previously discovered that freezing concentrates the RNA molecules in a liquid brine in tiny gaps between the ice crystals. This also is beneficial for the RNA enzymes, which are more stable and function better at cold temperatures.Dr Holliger added: "This is completely new synthetic biology and there are many aspects of the system that we have not yet explored. We hope in future, it will also have some biotechnology applications, such as adding chemical modifications at specific positions to RNA polymers to study RNA epigenetics or augment the function of RNA."Dr Nathan Richardson, Head of Molecular and Cellular Medicine at the MRC, said: "This is a really exciting example of blue skies research that has revealed important insights into how the very beginnings of life may have emerged from the 'primordial soup' some 3.7 billion years ago. Not only is this fascinating science, but understanding the minimal requirements for RNA replication and how these systems can be manipulated could offer exciting new strategies for treating human disease."Research paper
  • Orbital variations can trigger 'snowball states' on exoplanets
    Freitag, 18.05.2018, 03:46:05 Uhr
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    Orbital variations can trigger 'snowball states' on exoplanets Seattle WA (SPX) May 15, 2018 -
    Aspects of an otherwise Earthlike planet's tilt and orbital dynamics can severely affect its potential habitability - even triggering abrupt "snowball states" where oceans freeze and surface life is impossible, according to new research from astronomers at the University of Washington.The research indicates that locating a planet in its host star's "habitable zone" - that swath of space just right to allow liquid water on an orbiting rocky planet's surface - isn't always enough evidence to judge potential habitability.Russell Deitrick, lead author of a paper to be published in the Astronomical Journal, said he and co-authors set out to learn, through computer modeling, how two features - a planet's obliquity or its orbital eccentricity - might affect its potential for life. They limited their study to planets orbiting in the habitable zones of "G dwarf" stars, or those like the Sun.A planet's obliquity is its tilt relative to the orbital axis, which controls a planet's seasons; orbital eccentricity is the shape, and how circular or elliptical - oval - the orbit is. With elliptical orbits, the distance to the host star changes as the planet comes closer to, then travels away from, its host star.Deitrick, who did the work while with the UW, is now a post-doctoral researcher at the University of Bern. His UW co-authors are atmospheric sciences professor Cecilia Bitz, astronomy professors Rory Barnes, Victoria Meadows and Thomas Quinn and graduate student David Fleming, with help from undergraduate researcher Caitlyn Wilhelm. Other co-authors are Benjamin Charnay, a former UW post-doctoral researcher now with the LESIA Observatoire de Paris; and John Armstrong of Weber State University, who earned his doctorate at the UW.The Earth hosts life successfully enough as it circles the Sun at an axial tilt of about 23.5 degrees, wiggling only a very little over the millennia. But, Deitrick and co-authors asked in their modeling, what if those wiggles were greater on an Earthlike planet orbiting a similar star?Previous research indicated that a more severe axial tilt, or a tilting orbit, for a planet in a Sun-like star's habitable zone - given the same distance from its star - would make a world warmer. So Deitrick and team were surprised to find, through their modeling, that the opposite reaction appears true."We found that planets in the habitable zone could abruptly enter 'snowball' states if the eccentricity or the semi-major axis variations - changes in the distance between a planet and star over an orbit - were large or if the planet's obliquity increased beyond 35 degrees," Deitrick said.The new study helps sort out conflicting ideas proposed in the past. It used a sophisticated treatment of ice sheet growth and retreat in the planetary modeling, which is a significant improvement over several previous studies, co-author Barnes said."While past investigations found that high obliquity and obliquity variations tended to warm planets, using this new approach, the team finds that large obliquity variations are more likely to freeze the planetary surface," he said. "Only a fraction of the time can the obliquity cycles increase habitable planet temperatures."Barnes said Deitrick "has essentially shown that ice ages on exoplanets can be much more severe than on Earth, that orbital dynamics can be a major driver of habitability and that the habitable zone is insufficient to characterize a planet's habitability." The research also indicates, he added, "that the Earth may be a relatively calm planet, climate-wise."This kind of modeling can help astronomers decide which planets are worthy of precious telescope time, Deitrick said: "If we have a planet that looks like it might be Earth-like, for example, but modeling shows that its orbit and obliquity oscillate like crazy, another planet might be better for follow-up with telescopes of the future."The main takeaway of the research, he added, is that "We shouldn't neglect orbital dynamics in habitability studies."Research Report: "Exo-Milankovitch Cycles II: Climates of G-dwarf Planets in Dynamically Hot Systems," Russell Deitrick et al., 2018, to appear in the Astronomical Journal
  • ANU study sheds new light on how our solar
    Freitag, 18.05.2018, 03:46:05 Uhr
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    ANU study sheds new light on how our solar Canberra, Australia (SPX) May 11, 2018 -
    A study led by The Australian National University (ANU) and the University of Crete in Greece has shed new light on the mystery of how our solar system formed in a cloud of gas and dust in space billions of years ago.Lead researcher Dr Aris Tritsis from ANU said the study visualised the 3D shape of a star-forming cloud called Musca, which appears as a needle in the southern sky.Musca lies hundreds of light years away from Earth. The large gas cloud, formed mainly of molecular hydrogen and dust, stretches about 27 light years across the plain of the sky, with a depth of about 20 light years and width up to a fraction of a light year."We were able to reconstruct the 3D structure of a gas cloud in its very early stages of making new stars and planets, which will ultimately take millions of years to form," said Dr Tritsis from the ANU Research School of Astronomy and Astrophysics."Knowledge of the 3D shape of clouds will greatly improve our understanding of these nurseries of stars and the birth of our own solar system."He said scientists could now use Musca as a model to learn how stars and planets formed."With its 3D shape now determined, Musca can be used as a laboratory for testing star formation, astrochemical and dust-formation theories," Dr Tritsis said."We see, for the first time, that this cloud is not a thin, static streak of gas in space, but a vibrating, complex structure. Despite its needle-like appearance, Musca actually resembles a sheet viewed edge-on."Musca is surrounded by ordered hair-like structures called striations, which are produced by trapped waves of gas and dust caused by the global vibrations of the cloud.The research team was able to determine the shape of Musca by analysing the spatial frequencies of these vibrations, which were then converted into ringing tones to reveal the 'Song of Musca'."This is a cloud in space that is singing to us - all we had to do was listen. It's actually quite awesome," Dr Tritsis said.In addition to providing new insights into star and planet formation, the model of Musca cloud can also be used to see how molecules form in gas clouds.Co-researcher Dr Konstantinos Tassis from the University of Crete said Musca was the largest structure in the Milky Way galaxy found to be vibrating as a whole."There's a whole range of new things we can learn from this model," Dr Tassis said.The study, which was part of Dr Tritsis' PhD thesis, has made use of data from the European Space Agency's Herschel space telescope.The research is published in Science.NASA has some high quality optical images of the Musca gas cloud, such as this one: https://apod.nasa.gov/apod/ap150910.html
  • Atmospheric seasons could signal alien life
    Freitag, 18.05.2018, 03:46:05 Uhr
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    Atmospheric seasons could signal alien life Riverside CA (SPX) May 10, 2018 -
    Dozens of potentially habitable planets have been discovered outside our solar system, and many more are awaiting detection. Is anybody - or anything - there?The hunt for life in these places, which are impossible to visit in person, will begin with a search for biological products in their atmospheres. These atmospheric fingerprints of life, called biosignatures, will be detected using next-generation telescopes that measure the composition of gases surrounding planets that are light years away.It's a tricky business, since biosignatures based on single measurements of atmospheric gases could be misleading. To complement these markers, and thanks to funding from the NASA Astrobiology Institute, scientists at the University of California, Riverside's Alternative Earths Astrobiology Center are developing the first quantitative framework for dynamic biosignatures based on seasonal changes in the Earth's atmosphere.Titled "Atmospheric Seasonality As An Exoplanet Biosignature," a paper describing the research was published in The Astrophysical Journal Letters. The lead author is Stephanie Olson, a graduate student in UCR's Department of Earth Sciences.As Earth orbits the sun, its tilted axis means different regions receive more rays at different times of the year. The most visible signs of this phenomenon are changes in the weather and length of the days, but atmospheric composition is also impacted. For example, in the Northern Hemisphere, which contains most of the world's vegetation, plant growth in summer results in noticeably lower levels of carbon dioxide in the atmosphere. The reverse is true for oxygen."Atmospheric seasonality is a promising biosignature because it is biologically modulated on Earth and is likely to occur on other inhabited worlds," Olson said."Inferring life based on seasonality wouldn't require a detailed understanding of alien biochemistry because it arises as a biological response to seasonal changes in the environment, rather than as a consequence of a specific biological activity that might be unique to the Earth."Further, extremely elliptical orbits rather than axis tilt could yield seasonality on extrasolar planets, or exoplanets, expanding the range of possible targets.In the paper, the researchers identify the opportunities and pitfalls associated with characterizing the seasonal formation and destruction of oxygen, carbon dioxide, methane, and their detection using an imaging technique called spectroscopy.They also modeled fluctuations of atmospheric oxygen on a life-bearing planet with low oxygen content, like that of Earth billions of years ago.They found that ozone (O3), which is produced in the atmosphere through reactions involving oxygen gas (O2) produced by life, would be a more easily measurable marker for the seasonal variability in oxygen than O2 itself on weakly oxygenated planets."It's really important that we accurately model these kinds of scenarios now, so the space and ground-based telescopes of the future can be designed to identify the most promising biosignatures," said Edward Schwieterman, a NASA Postdoctoral Program fellow at UCR. "In the case of ozone, we would need telescopes to include ultraviolet capabilities to easily detect it."Schwieterman said the challenge in searching for life is the ambiguity of data collected from so far away. False positives - nonbiological processes that masquerade as life - and false negatives - life on a planet that produces few or no biosignatures - are both major concerns."Both oxygen and methane are promising biosignatures, but there are ways they can be produced without life," Schwieterman said.Olson said observing seasonal changes in oxygen or methane would be more informative."A potentially powerful way to assess exoplanets for inhabitation would be to observe their atmospheres throughout their orbits to see if we can detect changes in these biosignature gases over the course of a year," she said."In some circumstances, such changes would be difficult to explain without life and may even allow us to make progress towards characterizing, rather than simply recognizing, life on an exoplanet."Timothy Lyons, a professor of biogeochemistry in UCR's Department of Earth Science and director of the Alternative Earths Astrobiology Center, said this work advances the fundamental approach to searching for life on very distant planets."We are particularly excited about the prospect of characterizing oxygen fluctuations at the low levels we would expect to find on an early version of Earth," Lyons said. "Seasonal variations as revealed by ozone would be most readily detectable on a planet like Earth was billions of years ago, when most life was still microscopic and ocean dwelling."Research paper
  • Dutch astronomers photograph possible toddler planet by chance
    Freitag, 18.05.2018, 03:46:05 Uhr
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    Dutch astronomers photograph possible toddler planet by chance Amsterdam, Netherlands (SPX) May 09, 2018 -
    An international team of astronomers headed by Dutch researchers from Leiden University has coincidently found a small companion around the young double star CS Cha. The astronomers examined the dust disc of the binary, while they stumbled upon the companion.The researchers suspect that it is a planet in his toddler years that is still growing. The astronomers used the SPHERE instrument on the European Very Large Telescope in Chile. They will soon publish their findings in an article that is accepted by the journal Astronomy and Astrophysics.The binary star CS Cha and his special companion are located some six hundred light years away from Earth in a star formation area in the southern constellation Chameleon. The double star is just two to three million years young. The researchers wanted to study the star to search for a dust disc and for planets in the making.During their research on the binary star, the astronomers saw a small dot on the edge of their images. The researchers dived into the telescope archives and discovered the dot, but much fainter, also on 19 year old photographs taken with the Hubble Space Telescope and on 11 year old photographs of the Very Large Telescope.Thanks to the old photographs, the astronomers were able to show that the companion moves with the binary and that they belong together.What the companion looks like and how it was formed is unclear. The researchers tried to fit various models on the observations, but they do not give a hundred percent certainty. The companion may be a small brown dwarf star, but it can also be a big super-Jupiter.Lead author Christian Ginski (Leiden Observatory, Leiden University) explains: "The most exciting part is that the light of the companion is highly polarized. Such a preference in the direction of polarization usually occurs when light is scattered along the way. We suspect that the companion is surrounded by his own dust disc."The tricky part is that the disc blocks a large part of the light and that is why we can hardly determine the mass of the companion. So it could be a brown dwarf but also a super-Jupiter in his toddler years. The classical planet-forming-models can't help us."In the future, the researchers want to examine the star and the companion in more detail. They want to use the international ALMA telescope on the Chajnantor plateau in the North Chilean Andes.SPHERE is the abbreviation of Spectro-Polarimetric High-contrast Exoplanet REsearch instrument. It is a powerful planet hunter that is attached to the European Very Large Telescope at Cerro Paranal in northern Chile.The instrument has partly been developed in the Netherlands. SPHERE can make direct images of exoplanets and dust discs around stars. The instrument bypasses the bright star and looks specifically at polarized light that is reflected by the atmosphere of an exoplanet or the dust disc around a star.Research Report: "First direct detection of a polarized companion outside of a resolved circumbinary disk around CS Cha*"
  • An Exoplanet Atmosphere Free of Clouds
    Freitag, 18.05.2018, 03:46:05 Uhr
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    An Exoplanet Atmosphere Free of Clouds Exeter UK (SPX) May 08, 2018 -
    Scientists have detected an exoplanet atmosphere that is free of clouds, marking a pivotal breakthrough in the quest for greater understanding of the planets beyond our solar system.An international team of astronomers, led by Dr. Nikolay Nikolov from the University of Exeter, have found that the atmosphere of the 'hot Saturn' WASP-96b is cloud-free.Using Europe's 8.2-meter Very Large Telescope in Chile, the team studied the atmosphere of WASP-96b when the planet passed in front of its host star. This enabled the team to measure the decrease of starlight caused by the planet and its atmosphere, and thereby determine the planet's atmospheric composition.Just like an individual's fingerprints are unique, atoms and molecules have a unique spectral characteristic that can be used to detect their presence in celestial objects. The spectrum of WASP-96b shows the complete fingerprint of sodium, which can only be observed for an atmosphere free of clouds.The results are published in prestigious research journal Nature on May 7, 2018.WASP-96b is a typical 1,300 kelvin hot gas giant similar to Saturn in mass and exceeding the size of Jupiter by 20%. The planet periodically transits a Sun-like star 980 light-years away in the southern constellation Phoenix, halfway between the southern jewels Fomalhaut (Alpha Piscis Austrini) and Achernar (Alpha Eridani).It has long been predicted that sodium exists in the atmospheres of hot gas-giant exoplanets, and in a cloud-free atmosphere it would produce spectra that are similar in shape to the profile of a camping tent.Nikolay Nikolov, lead author and from the University of Exeter said, "We've been looking at more than twenty exoplanet transit spectra. WASP-96b is the only exoplanet that appears to be entirely cloud-free and shows such a clear sodium signature, making the planet a benchmark for characterization.""Until now, sodium was revealed either as a very narrow peak or found to be completely missing. This is because the characteristic 'tent-shaped' profile can only be produced deep in the atmosphere of the planet and for most planet clouds appear to get in the way."Clouds and hazes are known to exist in some of the hottest and coldest solar system planets and exoplanets. The presence or absence of clouds and their ability to block light plays an important role in the overall energy budget of planetary atmospheres."It is difficult to predict which of these hot atmospheres will have thick clouds. By seeing the full range of possible atmospheres, from very cloudy to nearly cloud-free like WASP-96b, we'll gain a better understanding of what these clouds are made of," explains Professor Jonathan J. Fortney, study co-author, based at the Other Worlds Laboratory (OWL) at the University of California, Santa Cruz (UCSC).The sodium signature seen in WASP-96b suggests an atmosphere free of clouds. The observation allowed the team to measure how abundant sodium is in the atmosphere of the planet, finding levels similar to those found in our own solar system."WASP-96b will also provide us with a unique opportunity to determine the abundances of other molecules, such as water, carbon monoxide and carbon dioxide with future observations," adds co-author Ernst de Mooij from Dublin City University.Sodium is the seventh most common element in the universe. On Earth, sodium compounds such as salt give sea water its salty taste and the white colour of salt pans in deserts. In animal life, sodium is known to regulate heart activity and metabolism. Sodium is also used in technology, such as in the sodium-vapour street lights, where it produces yellow-orange light.The team aims to look at the signature of other atmospheric species, such as water, carbon monoxide and carbon dioxide with the Hubble and James Webb Space Telescopes as well as telescopes on the ground.'An Absolute Sodium Abundance for a Cloud-Free 'Hot Saturn' Exoplanet," Nikolay Nikolov et al., 2018 May 7, Nature
  • The Cheops ccience instrument arrives in Madrid
    Freitag, 18.05.2018, 03:46:05 Uhr
    The Cheops ccience instrument arrives in Madrid Madrid, Spain (ESA) May 04, 2018 -
    Members of the CHEOPS consortium could be proud of their achievement as the science instrument of the upcoming exoplanet mission left Bern on its journey to Madrid last month.The science instrument and its tailor-made handling equipment left Switzerland by truck in six containers, designed to provide protection from shock, moisture and dust, on 10 April 2018. Its safe arrival in Spain the following day marked a key milestone for the CHEOPS project and enabled Airbus Defence and Space Spain, the prime contractor that has designed the spacecraft, to integrate the science instrument and the spacecraft platform and begin test activities.The science instrument, including among other elements the telescope and Charge Coupled Detector, or CCD, cannot operate without the satellite platform, which comprises solar panels, thrusters, radio transmitters and reaction wheels for providing power, propulsion, communications and attitude control.The shipment of the science instrument follows an intense period of qualification and calibration activities at the University of Bern, with the instrument team racing against the clock to deliver the instrument to the spacecraft prime contractor so that CHEOPS can be ready for launch by the end of this year. The key objective of the calibration campaign was to collect the data needed to convert the signals measured by the instrument into values that can be used to determine astrophysically meaningful quantities.CHEOPS will make observations of exoplanet-hosting stars to measure small changes in their brightness due to the transit of a planet across the star disc.The light from point-like stars will be collected by the telescope and directed onto multiple pixels of the detector to form an image that astronomers call the 'point spread function'. Knowledge of the shape of the point spread function is needed to make sure that the instrument is used in an optimal way. It is essential that any changes in the measured signal caused by transiting planets can be distinguished from changes caused by environmental effects such as variations in the temperature of the instrument or electromagnetic disturbances.The calibration campaign conducted in Bern over the past three months involved such sensitive measurements that even the body heat of people in the cleanroom housing the reference sources had to be taken into account. Reassuringly, it was determined that the thermal stability of the telescope was satisfactory and even exceeded the design requirements.A number of calibration activities focused on the electronics of the CHEOPS detector. As photons from CHEOPS target stars strike the silicon surface of the CCD, they will be converted into electrons. The resulting charge will be turned into a voltage that must be sampled and digitised. The response of the electronics in this process is unique to CHEOPS and must be calibrated and optimised.As a result of the tests completed in Bern, astronomers believe that the CHEOPS instrument can achieve the scientific objectives for which it has been built, and it is with hope and excitement that they can look forward to the new science that the satellite will enable once operating in space.Once the final integration checks have been made in Madrid and the last calibration data have been analysed, most members of the instrument team in Bern will be able to consider their job done. After much hard work, they will be looking forward to the launch eagerly.Others will continue work on the remaining elements of the mission, starting with the team at Airbus Defence and Space Spain. The upcoming activities will provide an opportunity to train the future operations team and will include system validation tests to ensure smooth end-to-end operations involving the integrated spacecraft, the mission operations centre in Torrejon, Spain, and the science operations centre in Geneva, Switzerland. These tests will be followed by thermal tests in France, vibration tests in Switzerland and acoustic tests at ESTEC, ESA's technical centre in The Netherlands.
  • Helium detected in exoplanet atmosphere for the first time
    Freitag, 18.05.2018, 03:46:05 Uhr
    Helium detected in exoplanet atmosphere for the first time Exeter UK (SPX) May 03, 2018 -
    Astronomers have detected helium in the atmosphere of a planet that orbits a star far beyond our solar system for the very first time.An international team of researchers, led by Jessica Spake from the University of Exeter, discovered evidence of the inert gas on 'super-Neptune' exoplanet WASP-107b, found 200 light years from Earth and in the constellation of Virgo.The pivotal breakthrough, made from observations of the exoplanet using the Hubble Space Telescope, revealed an abundance of helium in the upper atmosphere of the exoplanet, which was only discovered in 2017.The strength of the helium signal detected was so large that scientists believe the planet's upper atmosphere extends tens of thousands of kilometres into space.Helium is the second most common element in the universe and it has long-since been predicted to be one of the most readily-detectable gases on giant exoplanets. However, this pioneering new research is the first time that the gas has been successfully found.Now, the research team believe that the ground-breaking study could pave the way for scientists to discover more atmospheres around Earth-sized exoplanets across the galaxy.The research is published in the leading scientific journal, Nature, on May 3, 2018.Jessica Spake, part of Exeter's Physics and Astronomy department said: "We hope to use this technique with the upcoming James Webb Space Telescope, for example, to learn what kind of planets have large envelopes of hydrogen and helium, and how long planets can hold on to their atmospheres. By measuring infrared light, we can see further out into space than if we were using ultraviolet light."WASP-107b is a very low-density planet similar in size to Jupiter, but with only 12 per cent of its mass. Orbiting its host star every six days, it has one of the coolest atmospheres of any of the exoplanets discovered, although at 500 C is still radically hotter that Earth.By analysing the spectrum of light passing through the upper part of the exoplanet's atmosphere, the researchers were able to detect the presence of helium in an excited state.The significant strength of the signal measured exploited a new technique that doesn't rely on ultraviolet measurements which have historically been used to study upper exoplanet atmospheres. The team believe this new technique, which uses infrared light, could open up new paths to exploring the atmospheres of more Earth-sized exoplanets found in the further reaches of the universe.Tom Evans, a co-author also from the University of Exeter added: "The helium we detected extends far out to space as a tenuous cloud surrounding the planet. If smaller, Earth-sized planets have similar helium clouds, this new technique offers an exciting means to study their upper atmospheres in the very near future.."Helium was first detected as an unknown yellow spectral line signature in sunlight in 1868. Devon-based astronomer Norman Lockyer was the first to propose this line was due to a new element, and named it after the Greek Titan of the Sun, Helios.It has since been discovered to be one of the main constituents of the planets Jupiter and Saturn in our Solar System.
  • Hubble detects helium in the atmosphere of an exoplanet for the first time
    Freitag, 18.05.2018, 03:46:05 Uhr
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    Hubble detects helium in the atmosphere of an exoplanet for the first time Munich, Germany (SPX) May 03, 2018 -
    Astronomers using the NASA/ESA Hubble Space Telescope have detected helium in the atmosphere of the exoplanet WASP-107b. This is the first time this element has been detected in the atmosphere of a planet outside the Solar System. The discovery demonstrates the ability to use infrared spectra to study exoplanet extended atmospheres.The international team of astronomers, led by Jessica Spake, a PhD student at the University of Exeter in the UK, used Hubble's Wide Field Camera 3 to discover helium in the atmosphere of the exoplanet WASP-107b This is the first detection of its kind.Spake explains the importance of the discovery: "Helium is the second-most common element in the Universe after hydrogen. It is also one of the main constituents of the planets Jupiter and Saturn in our Solar System. However, up until now helium had not been detected on exoplanets - despite searches for it."The team made the detection by analysing the infrared spectrum of the atmosphere of WASP-107b. Previous detections of extended exoplanet atmospheres have been made by studying the spectrum at ultraviolet and optical wavelengths; this detection therefore demonstrates that exoplanet atmospheres can also be studied at longer wavelengths."The strong signal from helium we measured demonstrates a new technique to study upper layers of exoplanet atmospheres in a wider range of planets," says Spake "Current methods, which use ultraviolet light, are limited to the closest exoplanets. We know there is helium in the Earth's upper atmosphere and this new technique may help us to detect atmospheres around Earth-sized exoplanets - which is very difficult with current technology."WASP-107b is one of the lowest density planets known: While the planet is about the same size as Jupiter, it has only 12% of Jupiter's mass. The exoplanet is about 200 light-years from Earth and takes less than six days to orbit its host star.The amount of helium detected in the atmosphere of WASP-107b is so large that its upper atmosphere must extend tens of thousands of kilometres out into space. This also makes it the first time that an extended atmosphere has been discovered at infrared wavelengths.Since its atmosphere is so extended, the planet is losing a significant amount of its atmospheric gases into space - between ~0.1-4% of its atmosphere's total mass every billion years [2].As far back as the year 2000, it was predicted that helium would be one of the most readily-detectable gases on giant exoplanets, but until now, searches were unsuccessful.David Sing, co-author of the study also from the University of Exeter, concludes: "Our new method, along with future telescopes such as the NASA/ESA/CSA James Webb Space Telescope/, will allow us to analyse atmospheres of exoplanets in far greater detail than ever before."Research Report: "Helium in the eroding atmosphere of an exoplanet"
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