WASP-31b

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WASP-31b
HotJupiter-Exoplanet-WASP-31b.jpg
"Hot Jupiter" exoplanet WASP-31b (artist concept)
Discovery
Discovered by Anderson, D.R. et al. [1]
Discovery site WASP [2]
Discovery date2010 [2]
Primary transit [2]
Orbital characteristics
0.04657±0.00034 AU
Eccentricity 0 [2]
3.40591 [2] d
Inclination 84.54±0.027 [2]
StarWASP-31 [2]
Physical characteristics
1.537±0.06 [2] RJ
Mass 0.478±0.03 [2] MJ

    WASP-31b is a low-density (puffy) "hot Jupiter" extrasolar planet orbiting the metal-poor (63% of solar metallicity) dwarf star WASP-31. [1] The exoplanet was discovered in 2010 by the WASP project. [2] [1] WASP-31b is in the constellation of Crater, [3] and is about 1305 light-years [4] (light travel distance) from Earth. [2]

    Contents

    Characteristics

    WASP-31b is a low-density (puffy) "hot Jupiter" exoplanet with a mass about 0.48 times that of Jupiter and a radius about 1.55 times that of Jupiter. [2] [1] The planetary atmosphere has indeed the largest scale height, equal to 1150km, among exoplanets with measurable atmospheres as at 2021. [5]

    The exoplanet orbits WASP-31, its host star, every 3.4 days. [2]

    Comparison of "hot Jupiter" exoplanets, including WASP-31b (top row; 3rd from left) (artist concept) From top left to lower right: WASP-12b, WASP-6b, WASP-31b, WASP-39b, HD 189733b, HAT-P-12b, WASP-17b, WASP-19b, HAT-P-1b and HD 209458b. Clear to cloudy hot Jupiters.jpg
    Comparison of "hot Jupiter" exoplanets, including WASP-31b
    (top row; 3rd from left) (artist concept)

    From top left to lower right: WASP-12b, WASP-6b, WASP-31b, WASP-39b, HD 189733b, HAT-P-12b, WASP-17b, WASP-19b, HAT-P-1b and HD 209458b.

    In 2012, it was found from the Rossiter–McLaughlin effect that WASP-31b is orbiting the parent star in a prograde direction, with the WASP-31 star rotational axis inclined to the planetary orbit by 2.8±3.1 degrees. [6] The spectroscopic study in 2014 revealed that WASP-31b has a dense cloud deck overlaid by a hazy atmosphere. [7] WASP-31b was also reported to have significant amounts of potassium in its upper atmosphere, but the detection of potassium was refuted in 2015. [8] The potassium detection discrepancy was resolved in 2020 with the improved cloud deck model, [9] with the best fit being a very small amount of water over clouds and no potassium at all. [10]

    Reanalysis of planetary spectroscopic data in 2020 has revealed the presence of chromium monohydride besides water. [11]

    See also

    Related Research Articles

    <span class="mw-page-title-main">HD 189733 b</span> Hot Jupiter exoplanet in the constellation Vulpecula

    HD 189733 b is an exoplanet in the constellation of Vulpecula approximately 64.5 light-years away from the Solar System. Astronomers in France discovered the planet orbiting the star HD 189733 on October 5, 2005, by observing its transit across the star's face. With a mass 11.2% higher than that of Jupiter and a radius 11.4% greater, HD 189733 b orbits its host star once every 2.2 days at an orbital speed of 152.0 kilometers per second, making it a hot Jupiter with poor prospects for extraterrestrial life.

    <span class="mw-page-title-main">WASP-6b</span> Extrasolar planet

    WASP-6b, also named Boinayel, is an exoplanet approximately 650 light years away in the constellation Aquarius. It was discovered in 2008, by the WASP survey, by astronomical transit across its parent star WASP-6. This planet orbits at only 4% of the Earth-Sun distance. The planet has a mass half that of Jupiter, but its insolation has forced a thermal expansion of its radius to greater than that of Jupiter. Thus, this planet is an inflated hot Jupiter. Starspots on the host star WASP-6 helped to refine the measurements of the mass and the radius of the planet.

    <span class="mw-page-title-main">WASP-17b</span> Hot-Jupiter exoplanet in the orbit of the star WASP-17

    WASP-17b, officially named Ditsö̀, is an exoplanet in the constellation Scorpius that is orbiting the star WASP-17. Its discovery was announced on 11 August 2009. It is the first planet discovered to have a retrograde orbit, meaning it orbits in a direction counter to the rotation of its host star. This discovery challenged traditional planetary formation theory. In terms of diameter, WASP-17b is one of the largest exoplanets discovered and at half Jupiter's mass, this made it the most puffy planet known in 2010. On 3 December 2013, scientists working with the Hubble Space Telescope reported detecting water in the exoplanet's atmosphere.

    WASP-33b is an extrasolar planet orbiting the star HD 15082. It was the first planet discovered to orbit a Delta Scuti variable star. With a semimajor axis of 0.026 AU and a mass likely greater than Jupiter's, it belongs to the hot Jupiter class of planets.

    <span class="mw-page-title-main">WASP-43b</span> Extrasolar planet in the constellation Sextans

    WASP-43b, formally named Astrolábos, is a transiting planet in orbit around the young, active, and low-mass star WASP-43 in the constellation Sextans. The planet is a hot Jupiter with a mass twice that of Jupiter, but with a roughly equal radius. WASP-43b was flagged as a candidate by the SuperWASP program, before they conducted follow-ups using instruments at La Silla Observatory in Chile, which confirmed its existence and provided orbital and physical characteristics. The planet's discovery was published on April 14, 2011.

    <span class="mw-page-title-main">WASP-121b</span> Hot Jupiter exoplanet orbiting WASP-121

    WASP-121b, formally named Tylos, is an exoplanet orbiting the star WASP-121. WASP-121b is the first exoplanet found to contain water in an extrasolar planetary stratosphere. WASP-121b is in the constellation Puppis, and is about 858 light-years from Earth.

    <span class="mw-page-title-main">WASP-39b</span> Exoplanet in constellation of Virgo

    WASP-39b, officially named Bocaprins, is a "hot Jupiter" extrasolar planet discovered in February 2011 by the WASP project, notable for containing a substantial amount of water in its atmosphere. In addition WASP-39b was the first exoplanet found to contain carbon dioxide in its atmosphere, and likewise for sulfur dioxide.

    HD 146389, is a star with a yellow-white hue in the northern constellation of Hercules. The star was given the formal name Irena by the International Astronomical Union in January 2020. It is invisible to the naked eye with an apparent visual magnitude of 9.4 The star is located at a distance of approximately 446 light years from the Sun based on parallax, but is drifting closer with a radial velocity of −9 km/s. The star is known to host one exoplanet, designated WASP-38b or formally named 'Iztok'.

    Qatar-2 is a K-type main-sequence star about 595 light-years away in the constellation of Virgo. The star is much older than Sun, and has a concentration of heavy elements similar to solar abundance. The star features a numerous and long-lived starspots, and belongs to a peculiar variety of inflated K-dwarfs with strong magnetic activity inhibiting internal convection.

    WASP-78, is a single F-type main-sequence star about 2350 light-years away. It is likely to be younger than the Sun at 3.4+1.5
    −0.8     billion years. WASP-78 is depleted in heavy elements, having a 45% concentration of iron compared to the Sun.

    BD-07 436, also known as WASP-77 since 2012, is a binary star system about 344 light-years away. The star's components appears to have a different age, with the secondary older than 9 billion years, while the primary's age is 5 billion years. The BD-07 436 system's concentration of heavy elements is similar to the Sun. Its stars display moderate chromospheric activity, including x-ray flares.

    WASP-52 is a K-type main-sequence star about 570 light-years away. It is older than the Sun at 10.7+1.9
    −4.5     billion years, but it has a similar fraction of heavy elements. The star has prominent starspot activity, with 3% to 14% of the stellar surface covered by areas 575±150 K cooler than the rest of the photosphere.

    WASP-69, also named Wouri, is a K-type main-sequence star 164 light-years away. Its surface temperature is 4782±15 K. WASP-69 is slightly enriched in heavy elements compared to the Sun, with a metallicity Fe/H index of 0.10±0.01, and is much younger than the Sun at 2 billion years. The data regarding starspot activity of WASP-69 are inconclusive, but spot coverage of the photosphere may be very high.

    WASP-88 is a F-type main-sequence star. Its surface temperature is 6450±61 K. WASP-88 is similar to the Sun in its concentration of heavy elements, with a metallicity Fe/H index of 0.03±0.04, and is younger at an age of 3.0±1.3 billion years.

    WASP-84, also known as BD+02 2056, is a G-type main-sequence star 327 light-years away in the constellation Hydra. Its surface temperature is 5350±31 K and is slightly enriched in heavy elements compared to the Sun, with a metallicity Fe/H index of 0.05±0.02. It is rich in carbon and depleted of oxygen. WASP-84's age is probably older than the Sun at 8.5+4.1
    −5.5     billion years. The star appears to have an anomalously small radius, which can be explained by the unusually high helium fraction or by it being very young.

    WASP-80 is a K-type main-sequence star about 162 light-years away from Earth. The star's age is much younger than the Sun's at 1.352±0.222 billion years. WASP-80 could be similar to the Sun in concentration of heavy elements, although this measurement is highly uncertain.

    References

    1. 1 2 3 4 Anderson, D.R.; et al. (2011). "WASP-31b: a low-density planet transiting a metal-poor, late-F-type dwarf star" (PDF). Astronomy & Astrophysics . 531: A60. arXiv: 1011.5882 . Bibcode:2011A&A...531A..60A. doi:10.1051/0004-6361/201016208. S2CID   20154835.
    2. 1 2 3 4 5 6 7 8 9 10 11 12 13 Staff (2018). "Planet WASP-31 b". Extrasolar Planets Encyclopaedia . Retrieved 2 March 2018.
    3. ↑ DJM (2018). "Finding the constellation which contains given sky coordinates". djm.cc. Retrieved 2 March 2018.
    4. ↑ Kyle (2018). "Convert Parsecs to Light Years". KylesConverter.com. Retrieved 2 March 2018.
    5. ↑ Baxter, Claire; Désert, Jean-Michel; Tsai, Shang-Min; Todorov, Kamen O.; Bean, Jacob L.; Deming, Drake; Parmentier, Vivien; Fortney, Jonathan J.; Line, Michael; Thorngren, Daniel; Pierrehumbert, Raymond T.; Burrows, Adam; Showman, Adam P. (2021), "Evidence for disequilibrium chemistry from vertical mixing in hot Jupiter atmospheres", Astronomy & Astrophysics, 648: A127, arXiv: 2103.07185 , doi:10.1051/0004-6361/202039708, S2CID   232222174
    6. ↑ Brown, D. J. A.; Cameron, A. Collier; Anderson, D. R.; Enoch, B.; Hellier, C.; Maxted, P. F. L.; Miller, G. R. M.; Pollacco, D.; Queloz, D.; Simpson, E.; Smalley, B.; Triaud, A. H. M. J.; Boisse, I.; Bouchy, F.; Gillon, M.; Hébrard, G. (2012). "Rossiter-Mc Laughlin effect measurements for WASP-16, WASP-25 and WASP-31★". Monthly Notices of the Royal Astronomical Society. 423 (2): 1503–1520. arXiv: 1203.4971 . Bibcode:2012MNRAS.423.1503B. doi: 10.1111/j.1365-2966.2012.20973.x . S2CID   53445367.
    7. ↑ "The atmosphere of hot-Jupiter exoplanet WASP-31b". 30 October 2014.
    8. ↑ Gibson, Neale P.; De Mooij, Ernst J W.; Evans, Thomas M.; Merritt, Stephanie; Nikolov, Nikolay; Sing, David K.; Watson, Chris (2019). "Revisiting the potassium feature of WASP-31b at high resolution". Monthly Notices of the Royal Astronomical Society. 482 (1): 606–615. arXiv: 1810.03693 . Bibcode:2019MNRAS.482..606G. doi: 10.1093/mnras/sty2722 .
    9. ↑ Chouqar, J.; Morales, M. L.; Daassou, A.; Jabiri, A.; Benkhaldoun, Z. (27 August 2018). "Modeling the Transmission Spectra of WASP-31b". Proceedings of the International Astronomical Union. 14 (S345): 383–385. doi:10.1017/S1743921319002953 – via Cambridge University Press.
    10. ↑ McGruder, Chima D.; López-Morales, Mercedes; Espinoza, Néstor; Rackham, Benjamin V.; Apai, Dániel; Jordán, Andrés; Osip, David J.; Alam, Munazza K.; Bixel, Alex; Fortney, Jonathan J.; Henry, Gregory W.; Kirk, James; Lewis, Nikole K.; Rodler, Florian; Weaver, Ian C. (2020), "ACCESS: Confirmation of No Potassium in the Atmosphere of WASP-31b", The Astronomical Journal, 160 (5): 230, arXiv: 2009.08472 , Bibcode:2020AJ....160..230M, doi: 10.3847/1538-3881/abb806 , S2CID   221802525
    11. ↑ Braam, Marrick; Van Der Tak, Floris F. S.; Chubb, Katy L.; Min, Michiel (2021), "Evidence for chromium hydride in the atmosphere of hot Jupiter WASP-31b", Astronomy & Astrophysics, 646: A17, arXiv: 2011.10558 , Bibcode:2021A&A...646A..17B, doi:10.1051/0004-6361/202039509, S2CID   227118876

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