Carbon Chemist

Tag: exoplanets

  • the neuroscience behind working memory

    the neuroscience behind working memory

    [ad_1]

    Download the Nature Podcast 17 April 2024

    In this episode:

    00:46 Mysterious methane emission from a cool brown dwarf

    The James Webb Space Telescope (JWST) is revealing the makeup of brown dwarfs — strange space objects that blur the line between a planet and a star. And it appears that methane in the atmosphere of one of these objects, named W1935, is emitting infrared radiation. Where the energy comes from is a mystery however, researchers hypothesise that the glow could be caused by an aurora in the object’s atmosphere, perhaps driven by an as-yet unseen moon.

    Research Article: Faherty et al.

    10:44 Research Highlights

    The discovery that bitter taste receptors may date back 450 million years, and the first planet outside the Solar System to boast a rainbow-like phenomenon called a ‘glory’.

    Research Highlight: Bitter taste receptors are even older than scientists thought

    Research Highlight: An exoplanet is wrapped in glory

    13:07 How working memory works

    Working memory is a fundamental process that allows us to temporarily store important information, such as the name of a person we’ve just met. However distractions can easily interrupt this process, leading to these memories vanishing. By looking at the brain activity of people doing working-memory tasks, a team have now confirmed that working memory requires two brain regions: one to hold a memory as long as you focus on it; and another to control its maintenance by helping you to not get distracted.

    Research article: Daume et al.

    News and Views: Coupled neural activity controls working memory in humans

    22:31 Briefing Chat

    The bleaching event hitting coral around the world, and the first evidence of a nitrogen-fixing eukaryote.

    New York Times: The Widest-Ever Global Coral Crisis Will Hit Within Weeks, Scientists Say

    Nature News: Scientists discover first algae that can fix nitrogen — thanks to a tiny cell structure

    Nature video: AI and robotics demystify the workings of a fly’s wing

    Vote for us in the Webbys: https://go.nature.com/3TVYHmP

    Subscribe to Nature Briefing, an unmissable daily round-up of science news, opinion and analysis free in your inbox every weekday.

    Subscribe to Nature Briefing: AI and robotics

    Never miss an episode. Subscribe to the Nature Podcast on Apple Podcasts, Spotify, YouTube Music or your favourite podcast app. An RSS feed for the Nature Podcast is available too.

    [ad_2]

    Source link

  • Planets that look alike might be a sign of spacefaring aliens

    Planets that look alike might be a sign of spacefaring aliens

    [ad_1]

    Alien civilisations that have terraformed multiple planets may be detectable from afar

    dotted zebra/Alamy

    Nearby planets that look unusually alike could be a sign of spacefaring alien life that has travelled between stars, researchers have suggested.

    Astronomers searching for extraterrestrial life tend to look for specific signals, either in the form of “biosignatures” – molecules that are only produced by biological processes – or “technosignatures”, abnormal patterns of light that may have been produced by technologies.

    Both of these rely on assumptions…

    [ad_2]

    Source link

  • An exoplanet is wrapped in glory

    An exoplanet is wrapped in glory

    [ad_1]

    When looking down on a cloud from an aeroplane, you can sometimes spot an iridescent aura surrounding the plane’s shadow. It is a ‘glory’, a phenomenon reminiscent of a rainbow but arising through a different mechanism. Astronomers could now have made the first sighting of a glory outside the Solar System1.

    Access options

    Rent or buy this article

    Prices vary by article type

    from$1.95

    to$39.95

    Prices may be subject to local taxes which are calculated during checkout

    doi: https://doi.org/10.1038/d41586-024-01032-5

    Subjects

    Latest on:


    [ad_2]
    Source link

  • Planet caught in a gravitational ‘tidal storm’ is so hot that it glows

    Planet caught in a gravitational ‘tidal storm’ is so hot that it glows

    [ad_1]

    Artist's impression of a super-Earth

    One rocky planet might be so hot it glows

    ESA/Hubble, M. Kornmesser

    A distant world is being stretched by the powerful gravity of its neighbouring planets and star to extremes never seen before in a rocky planet. The stretching is so intense that this strange world’s surface is probably entirely molten and so hot that it glows.

    Stephen Kane at the University of California, Riverside, and his colleagues spotted this unusual planet in a system already known to have one larger world, a giant planet circling the star once every 55 days…

    [ad_2]

    Source link

  • Billions of stars have swallowed up a planet

    Billions of stars have swallowed up a planet

    [ad_1]

    Artist's impression of a planet skimming the surface of its star

    Artist’s impression of a planet skimming the surface of its star

    K. Miller/R. Hurt (Caltech/IPAC)

    At least one star in every 12 seems to be a devourer of planets. This may be because star systems are readily destabilised when outside objects such as rogue worlds or other stars fly close by, and the disturbance can shake up planets’ orbits and throw them into their stars.

    Fan Liu at Monash University in Australia and his colleagues figured out how often this occurs by observing 91 pairs of stars using several of the world’s most powerful telescopes. They chose stars that were most likely born together in binaries, because these couples should have formed with identical chemical compositions. That way, the researchers could determine if one of them had swallowed up a planet in the past, because doing so would have changes its composition relative to its binary partner.

    They found that about 8 per cent of the pairs contained one star that had devoured a planet and therefore showed signs of a higher abundance of heavy elements than its twin. Those stars each appear to have ingested between 1.7 and 8.4 Earth masses of material. This matches with previous predictions.

    “Our estimates are conservative,” says Liu. “I would guess the actual rate might be higher, but probably still less than or around 20 per cent.” This may vary based on where in the galaxy a given star is born.

    Figuring out how many stars chow down on their planets is potentially a crucial part of understanding the abundance of life in the universe and how likely we are to find it.

    “It’s a question of, how many stars and planets are there that behave in a way that’s conducive to the development of life?” says Meridith Joyce at Konkoly Observatory in Hungary, part of the research team. “Knowing how many stars there are and how many stars host planets are two parts of that calculation, but we also need to know how many stars are going to eat those planets.”

    Topics:

    [ad_2]

    Source link

  • At least one in a dozen stars shows evidence of planetary ingestion

    [ad_1]

  • Pinsonneault, M. H., DePoy, D. L. & Coffee, M. The mass of the convective zone in FGK main-sequence stars and the effect of accreted planetary material on apparent metallicity determinations. Astrophys. J. Lett. 556, L59–L62 (2001).

    Article 
    CAS 

    Google Scholar     

  • Hühn, L. A. & Bitsch, B. How accretion of planet-forming disks influences stellar abundances. Astron. Astrophys. 676, 87 (2023).

    Article 

    Google Scholar     

  • Meléndez, J., Asplund, M., Gustafsson, B. & Yong, D. The peculiar solar composition and its possible relation to planet formation. Astrophys. J. Lett. 704, L66–L70 (2009).

    Article 

    Google Scholar     

  • Booth, R. A. & Owen, J. E. Fingerprints of giant planets in the composition of solar twins. Mon. Not. R. Astron. Soc. 493, 5079–5088 (2020).

    Article 
    CAS 

    Google Scholar     

  • Lodders, K. Solar System abundances and condensation temperatures of the elements. Astrophys. J. 591, 1220–1247 (2003).

    Article 
    CAS 

    Google Scholar     

  • Chambers, J. E. Stellar elemental abundance patterns: implications for planet formation. Astrophys. J. 724, 92–97 (2010).

    Article 
    CAS 

    Google Scholar     

  • Adibekyan, V. Tc trends and clues to Galactic evolution. Astron. Astrophys. 564, L15 (2014).

    Article 

    Google Scholar     

  • Nissen, P. E. High-precision abundances of elements in solar twin stars. Trends with stellar age and elemental condensation temperature. Astron. Astrophys. 579, 52 (2015).

    Article 

    Google Scholar     

  • Ramírez, I. et al. The dissimilar chemical composition of the planet-hosting stars of the XO-2 binary system. Astrophys. J. 808, 13 (2015).

    Article 

    Google Scholar     

  • Saffe, C. Implications for chemical tagging studies. Astron. Astrophys. 604, L4 (2017).

    Article 

    Google Scholar     

  • Oh, S. et al. Kronos and Krios: evidence for accretion of a massive, rocky planetary system in a comoving pair of solar-type stars. Astrophys. J. 854, 138 (2018).

    Article 

    Google Scholar     

  • Nagar, T., Spina, L. & Karakas, A. I. The chemical signatures of planetary engulfment events in binary systems. Astrophys. J. Lett. 888, L9 (2020).

    Article 
    CAS 

    Google Scholar     

  • Galarza, J. Y., López-Valdivia, R. & Meléndez, J. Evidence of rocky planet engulfment in the wide binary system HIP 71726/HIP 71737. Astrophys. J. 922, 129 (2021).

    Article 
    CAS 

    Google Scholar     

  • Gaia Collaboration. Gaia Early Data Release 3. Summary of the contents and survey properties. Astron. Astrophys. 649, 1 (2021).

    Article 

    Google Scholar     

  • Kamdar, H. et al. Stars that move together were born together. Astrophys. J. Lett. 884, L42 (2019).

    Article 
    CAS 

    Google Scholar     

  • Nelson, T. et al. Distant relatives: the chemical homogeneity of comoving pairs identified in Gaia. Astrophys. J. 921, 118 (2021).

    Article 
    CAS 

    Google Scholar     

  • Dotter, A., Conroy, C., Cargile, P. & Asplund, M. The influence of atomic diffusion on stellar ages and chemical tagging. Astrophys. J. 840, 99 (2017).

    Article 

    Google Scholar     

  • Yong, D. et al. C3PO: towards a complete census of co-moving pairs of stars. I. High precision stellar parameters for 250 stars. Mon. Not. R. Astron. Soc. 526, 2181–2195 (2023).

    Article 

    Google Scholar     

  • Behmard, A., Dai, F., Brewer, J. M., Berger, T. A. & Howard, A. W. Planet engulfment detections are rare according to observations and stellar modelling. Mon. Not. R. Astron. Soc. 521, 2969–2987 (2023).

    Article 
    CAS 

    Google Scholar     

  • Ramírez, I., Meléndez, J. & Asplund, M. Accurate abundance patterns of solar twins and analogs. Does the anomalous solar chemical composition come from planet formation? Astron. Astrophys. 508, L17–L20 (2009).

    Article 

    Google Scholar     

  • Bitsch, B. & Izidoro, A. Giants are bullies: how their growth influences systems of inner sub-Neptunes and super-Earths. Astron. Astrophys. 674, 178 (2023).

    Article 

    Google Scholar     

  • Spina, L. et al. Chemical evidence for planetary ingestion in a quarter of Sun-like stars. Nat. Astron. 5, 1163–1169 (2021).

    Article 

    Google Scholar     

  • Tayar, J. & Joyce, M. Is thermohaline mixing the full story? Evidence for separate mixing events near the red giant branch bump. Astrophys. J. Lett. 935, L30 (2022).

    Article 

    Google Scholar     

  • Traxler, A., Garaud, P. & Stellmach, S. Numerically determined transport laws for fingering (‘thermohaline’) convection in astrophysics. Astrophys. J. Lett. 728, L29 (2011).

    Article 

    Google Scholar     

  • Brown, J. M., Pascale, G. & Stellmach, S. Chemical transport and spontaneous layer formation in fingering convection in astrophysics. Astrophys. J. 768, 34 (2013).

    Article 

    Google Scholar     

  • Izidoro, A. et al. Formation of planetary systems by pebble accretion and migration. Hot super-Earth systems from breaking compact resonant chains. Astron. Astrophys. 650, 152 (2021).

    Article 

    Google Scholar     

  • Matsumoto, Y. & Ogihara, M. Breaking resonant chains: destabilization of resonant planets due to long-term mass evolution. Astrophys. J. 893, 43 (2020).

    Article 

    Google Scholar     

  • Fressin, F. et al. The false positive rate of Kepler and the occurrence of planets. Astrophys. J. 766, 81 (2013).

    Article 

    Google Scholar     

  • Mulders, G. D., Pascucci, I., Apai, D. & Ciesla, F. J. The Exoplanet Population Observation Simulator. I. The inner edges of planetary systems. Astron. J. 156, 24–43 (2018).

    Article 

    Google Scholar     

  • Liu, F. et al. Detailed chemical compositions of planet-hosting stars—I. Exploration of possible planet signatures. Mon. Not. R. Astron. Soc. 495, 3961–3973 (2020).

    Article 
    CAS 

    Google Scholar     

  • Liu, F. et al. Detailed elemental abundances of binary stars: searching for signatures of planet formation and atomic diffusion. Mon. Not. R. Astron. Soc. 508, 1227–1240 (2021).

    Article 
    CAS 

    Google Scholar     

  • Liu, F., Asplund, M., Ramírez, I., Yong, D. & Meléndez, J. A high-precision chemical abundance analysis of the HAT-P-1 stellar binary: constraints on planet formation. Mon. Not. R. Astron. Soc. 442, L51–L55 (2014).

    Article 
    CAS 

    Google Scholar     

  • Meléndez, J. et al. The remarkable solar twin HIP 56948: a prime target in the quest for other Earths. Astron. Astrophys. 543, 29 (2012).

    Article 

    Google Scholar     

  • McKenzie, M. et al. The complex stellar system M 22: confirming abundance variations with high precision differential measurements. Mon. Not. R. Astron. Soc. 516, 3515–3531 (2022).

    Article 
    CAS 

    Google Scholar     

  • Sneden, C. The nitrogen abundance of the very metal-poor star HD 122563. Astrophys. J. 184, 839–849 (1973).

    Article 
    CAS 

    Google Scholar     

  • Sobeck, J. S. et al. The abundances of neutron-capture species in the very metal-poor globular cluster M15: a uniform analysis of red giant branch and red horizontal branch stars. Astron. J. 141, 175–192 (2011).

    Article 

    Google Scholar     

  • Castelli, F. & Kurucz, R. L. New grids of ATLAS9 model atmospheres. In Proc. IAU Symposium Vol. 210 (eds Piskunov, N. et al.) 20 (Cambridge University Press, 2003).

  • Kurucz, R. & Bell, B. Atomic line data. in Kurucz CD-ROM No. 23 (Harvard-Smithsonian Centre for Astrophysics, 1995); http://kurucz.harvard.edu/linelists.html.

  • Battistini, C. & Bensby, T. The origin and evolution of the odd-Z iron-peak elements Sc, V, Mn, and Co in the Milky Way stellar disk. Astron. Astrophys. 577, 9 (2015).

    Article 

    Google Scholar     

  • Amarsi, A. M., Asplund, M., Collet, R. & Leenaarts, J. Non-LTE oxygen line formation in 3D hydrodynamic model stellar atmospheres. Mon. Not. R. Astron. Soc. 455, 3735–3751 (2016).

    Article 
    CAS 

    Google Scholar     

  • Lind, K., Asplund, M., Barklem, P. S. & Belyaev, A. K. Non-LTE calculations for neutral Na in late-type stars using improved atomic data. Astron. Astrophys. 528, 103 (2011).

    Article 

    Google Scholar     

  • Bergemann, M. et al. Non-local thermodynamic equilibrium stellar spectroscopy with 1D and <3D> models. I. Methods and application to magnesium abundances in standard stars. Astrophys. J. 847, 15 (2017).

    Article 

    Google Scholar     

  • Nordlander, T. & Lind, K. Non-LTE aluminium abundances in late-type stars. Astron. Astrophys. 607, 75 (2017).

    Article 

    Google Scholar     

  • Bergemann, M. et al. Observational constraints on the origin of the elements. I. 3D NLTE formation of Mn lines in late-type stars. Astron. Astrophys. 631, 80 (2019).

    Article 

    Google Scholar     

  • Bensby, T., Feltzing, S. & Oey, M. S. Exploring the Milky Way stellar disk. A detailed elemental abundance study of 714 F and G dwarf stars in the solar neighbourhood. Astron. Astrophys. 562, 71 (2014).

    Article 

    Google Scholar     

  • Speagle, J. S. DYNESTY: a dynamic nested sampling package for estimating Bayesian posteriors and evidences. Mon. Not. R. Astron. Soc. 493, 3132–3158 (2020).

    Article 

    Google Scholar     

  • Asplund, M., Grevesse, N., Sauval, A. J. & Scott, P. The chemical composition of the Sun. Annu. Rev. Astron. Astrophys. 47, 481–522 (2009).

    Article 
    CAS 

    Google Scholar     

  • Michaud, G., Fontaine, G. & Beaudet, G. The lithium abundance—constraints on stellar evolution. Astrophys. J. 282, 206–213 (1984).

    Article 
    CAS 

    Google Scholar     

  • Liu, F. et al. Chemical (in)homogeneity and atomic diffusion in the open cluster M 67. Astron. Astrophys. 627, 117 (2019).

    Article 

    Google Scholar     

  • Théado, S. & Vauclair, S. Metal-rich accretion and thermohaline instabilities in exoplanet-host stars: consequences on the light elements abundances. Astrophys. J. 744, 123 (2012).

    Article 

    Google Scholar     

[ad_2]

Source link

  • JWST will officially begin searching for exomoons around other planets

    JWST will officially begin searching for exomoons around other planets

    [ad_1]

    Five exomoon programmes have been picked for the James Webb Space Telescope, raising the hopes of finding moons around exoplanets for the first time

    [ad_2]

    Source link

  • Weird white dwarf star has a metal scar after eating a planet

    Weird white dwarf star has a metal scar after eating a planet

    [ad_1]

    artist's impression ofWD 0816-310

    An artist’s impression of WD 0816-310, where astronomers have found a scar imprinted on its surface left when the star ingested a planet

    ESO/L. Calçada

    Astronomers have found a white dwarf star with a strange metallic scar on its surface. This blemish probably formed when the star ripped up and ate a small planet in its orbit.

    Researchers often spot white dwarfs with traces of metal in their atmospheres, which come from planets that have fallen into the star. It has long been thought that the metals should be distributed evenly across the surfaces of these so-called polluted white dwarfs, but Jay Farihi at University College London and his colleagues have found one with an odd, concentrated patch of metal.

    The researchers monitored the star, called WD 0816-310, over a period of two months using the Very Large Telescope in Chile. They found an opaque patch of metal over one of the white dwarf’s magnetic poles, blocking some of the star’s light as it rotated. This position indicates that the material was probably funnelled into the star by its magnetic field. “This is an identical process to the one that causes the aurora on Earth: charged particles following the magnetic field to the surface,” says Farihi.

    The planet that WD 0816-310 destroyed was small – probably around the same size as the asteroid Vesta in our solar system, which is about 525 kilometres across. Its innards are now displayed prominently on its host star, which could make it relatively easy to study what its geochemistry was like before it was devoured. Such studies may even be among the best ways to observe small worlds beyond our solar system, albeit after their demise.

    And there may be many more scarred stars just like this one. “When we find one that looks like an oddball, if oftentimes means that all of them look like that and we just weren’t asking the right questions,” says Farihi. “This is the first one, but it’s probably not the last.” In fact, the researchers have already found two white dwarfs that appear to have similar scars. Going back to make repeat observations of similar stars could unearth even more.

    Topics:

    [ad_2]

    Source link

  • Where are all the exomoons? The hunt for worlds orbiting alien planets

    Where are all the exomoons? The hunt for worlds orbiting alien planets

    [ad_1]

    New Scientist Default Image

    YEARS ago, when David Kipping lived in London, he would walk home through the city and look up at the moon. As an astronomer, its faintly glowing presence served as a nightly source of inspiration. “It was a reminder that moons were waiting for us around exoplanets,” he says. “It just made sense that we should look for them.”

    Finding exomoons – natural satellites of worlds beyond our solar system – would be thrilling. For a start, they may play a key role in determining the habitability of host planets by damping their wobbles, fostering a stable climate in the same way that our moon has done for Earth. They might also come in weird and wonderful configurations, such as rings of moons and moons with their own moons. But most excitingly, it is possible that some of them are more hospitable to life than exoplanets.

    Kipping, now at Cornell University in New York, is part of a small community of astronomers who search for exomoons. The statistics, at least, are on their side: we have found some 5500 exoplanets so far, and some of these could have dozens of moons. The trouble is, proving their existence isn’t straightforward. The two sightings Kipping has made so far are hotly disputed.

    But now, hope is on the horizon, with a host of new ways to search for these objects – from watching rogue planets that have abandoned their stars to monitoring the gravitational wobbles of exoplanets. Armed with these new techniques, and with new telescopes on the way, the moon…

    [ad_2]

    Source link

  • Why we’re finally on the cusp of finding exomoons around other planets

    Why we’re finally on the cusp of finding exomoons around other planets

    [ad_1]

    New Scientist Default Image

    YEARS ago, when David Kipping lived in London, he would walk home through the city and look up at the moon. As an astronomer, its faintly glowing presence served as a nightly source of inspiration. “It was a reminder that moons were waiting for us around exoplanets,” he says. “It just made sense that we should look for them.”

    Finding exomoons – natural satellites of worlds beyond our solar system – would be thrilling. For a start, they may play a key role in determining the habitability of host planets by damping their wobbles, fostering a stable climate in the same way that our moon has done for Earth. They might also come in weird and wonderful configurations, such as rings of moons and moons with their own moons. But most excitingly, it is possible that some of them are more hospitable to life than exoplanets.

    Kipping, now at Columbia University in New York, is part of a small community of astronomers who search for exomoons. The statistics, at least, are on their side: we have found some 5500 exoplanets so far, and some of these could have dozens of moons. The trouble is, proving their existence isn’t straightforward. The two sightings Kipping has made so far are hotly disputed.

    But now, hope is on the horizon, with a host of new ways to search for these objects – from watching rogue planets that have abandoned their stars to monitoring the gravitational wobbles of exoplanets. Armed with these new techniques, and with new telescopes on the way, the moon…

    [ad_2]

    Source link