• Hubble probes extreme weather on ultra-h

    From ScienceDaily@1:317/3 to All on Wednesday, April 06, 2022 22:30:40
    Hubble probes extreme weather on ultra-hot Jupiters

    Date:
    April 6, 2022
    Source:
    NASA/Goddard Space Flight Center
    Summary:
    Astronomers have discovered bloated Jupiter-sized worlds that are
    so precariously close to their parent star they are being roasted
    at seething temperatures above 3,000 degrees Fahrenheit. That's
    hot enough to vaporize most metals, including titanium. They have
    the hottest planetary atmospheres ever seen. Hubble astronomers
    are reporting on bizarre weather conditions on these sizzling
    worlds. It's raining vaporized rock on one planet, and another one
    has its upper atmosphere getting hotter rather than cooler because
    it is being 'sunburned' by intense ultraviolet (UV) radiation from
    its star.



    FULL STORY ==========================================================================
    In studying a unique class of ultra-hot exoplanets, NASA Hubble Space
    Telescope astronomers may be in the mood for dancing to the Calypso
    party song "Hot, Hot, Hot." That's because these bloated Jupiter-sized
    worlds are so precariously close to their parent star they are being
    roasted at seething temperatures above 3,000 degrees Fahrenheit. That's
    hot enough to vaporize most metals, including titanium. They have the
    hottest planetary atmospheres ever seen.


    ==========================================================================
    In two new papers, teams of Hubble astronomers are reporting on bizarre
    weather conditions on these sizzling worlds. It's raining vaporized rock
    on one planet, and another one has its upper atmosphere getting hotter
    rather than cooler because it is being "sunburned" by intense ultraviolet
    (UV) radiation from its star.

    This research goes beyond simply finding weird and quirky planet
    atmospheres.

    Studying extreme weather gives astronomers better insights into the
    diversity, complexity, and exotic chemistry taking place in far-flung
    worlds across our galaxy.

    "We still don't have a good understanding of weather in different
    planetary environments," said David Sing of the Johns Hopkins University
    in Baltimore, Maryland, co-author on two studies being reported. "When
    you look at Earth, all our weather predictions are still finely tuned to
    what we can measure. But when you go to a distant exoplanet, you have
    limited predictive powers because you haven't built a general theory
    about how everything in an atmosphere goes together and responds to
    extreme conditions. Even though you know the basic chemistry and physics,
    you don't know how it's going to manifest in complex ways." In a paper
    in the April 7 journal Nature, astronomers describe Hubble observations
    of WASP-178b, located about 1,300 light-years away. On the daytime side
    the atmosphere is cloudless, and is enriched in silicon monoxide gas.

    Because one side of the planet permanently faces its star, the torrid atmosphere whips around to the nighttime side at super-hurricane speeds exceeding 2,000 miles per hour. On the dark side, the silicon monoxide
    may cool enough to condense into rock that rains out of clouds, but even
    at dawn and dusk, the planet is hot enough to vaporize rock. "We knew we
    had seen something really interesting with this silicon monoxide feature,"
    said Josh Lothringer of the Utah Valley University in Orem, Utah.

    In a paper published in the January 24 issue of Astrophysical Journal
    Letters, Guangwei Fu of the University of Maryland, College Park, reported
    on a super- hot Jupiter, KELT-20b, located about 400 light-years away. On
    this planet a blast of ultraviolet light from its parent star is creating
    a thermal layer in the atmosphere, much like Earth's stratosphere. "Until
    now we never knew how the host star affected a planet's atmosphere
    directly. There have been lots of theories, but now we have the first observational data," Fu said.

    By comparison, on Earth, ozone in the atmosphere absorbs UV light and
    raises temperatures in a layer between 7 to 31 miles above Earth's
    surface. On KELT- 20b the UV radiation from the star is heating metals
    in the atmosphere which makes for a very strong thermal inversion layer.

    Evidence came from Hubble's detection of water in near-infrared
    observations, and from NASA's Spitzer Space Telescope's detection
    of carbon monoxide. They radiate through the hot, transparent upper
    atmosphere that is produced by the inversion layer. This signature is
    unique from what astronomers see in the atmospheres of hot-Jupiters
    orbiting cooler stars, like our Sun. "The emission spectrum for KELT-20b
    is quite different from other hot-Jupiters," said Fu.

    "This is compelling evidence that planets don't live in isolation
    but are affected by their host star." Though super-hot Jupiters are uninhabitable, this kind of research helps pave the way to better
    understanding the atmospheres of potentially inhabitable terrestrial
    planets. "If we can't figure out what's happening on super-hot Jupiters
    where we have reliable solid observational data, we're not going to
    have a chance to figure out what's happening in weaker spectra from
    observing terrestrial exoplanets," said Lothringer. "This is a test
    of our techniques that allows us to build a general understanding of
    physical properties such as cloud formation and atmospheric structure."
    The Hubble Space Telescope is a project of international cooperation
    between NASA and ESA (European Space Agency). NASA's Goddard Space
    Flight Center in Greenbelt, Maryland, manages the telescope. The Space Telescope Science Institute (STScI) in Baltimore, Maryland, conducts
    Hubble science operations.

    STScI is operated for NASA by the Association of Universities for Research
    in Astronomy, in Washington, D.C.


    ========================================================================== Story Source: Materials provided by
    NASA/Goddard_Space_Flight_Center. Note: Content may be edited for style
    and length.


    ========================================================================== Journal References:
    1. Joshua D. Lothringer, David K. Sing, Zafar Rustamkulov, Hannah R.

    Wakeford, Kevin B. Stevenson, Nikolay Nikolov, Panayotis Lavvas,
    Jessica J. Spake, Autumn T. Winch. UV absorption by silicate
    cloud precursors in ultra-hot Jupiter WASP-178b. Nature, 2022;
    604 (7904): 49 DOI: 10.1038/ s41586-022-04453-2
    2. Guangwei Fu, David K. Sing, Joshua D. Lothringer, Drake Deming,
    Jegug Ih,
    Eliza M. -R. Kempton, Matej Malik, Thaddeus D. Komacek,
    Megan Mansfield, Jacob L. Bean. Strong H2O and CO Emission
    Features in the Spectrum of KELT-20b Driven by Stellar UV
    Irradiation. The Astrophysical Journal Letters, 2022; 925 (1):
    L3 DOI: 10.3847/2041-8213/ac4968 ==========================================================================

    Link to news story: https://www.sciencedaily.com/releases/2022/04/220406132402.htm

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