HIP 65Ab

Last updated
HIP 65Ab
Discovery [1]
Discovered by L. D. Nielsen et al.
Discovery dateJuly 2020 (announced)
Transit method
Designations
CD−55° 9423b, TIC 201248411 b, TOI-129 b, TYC 8464-1200-1 b, 2MASS J00004490-5449498 b [2]
Orbital characteristics [1]
0.01782+0.00020
−0.00021  AU
Eccentricity 0, [1] 0.009 [3]
0.9809734±0.0000031  d
Inclination 77.18°+0.92°
−1.00°
Semi-amplitude 753.7±5.0  m/s
Star HIP 65A
Physical characteristics [1]
<1.5  RJ
Mass 3.213±0.078  MJ , [1] ≥2.95 MJ [3]
Mean density
0.480+0.610
−0.260  g/cm3
Temperature 1411±15  K (1,138 °C; 2,080 °F, equilibrium)

    HIP 65Ab (TOI-129 b) is a hot Jupiter discovered in 2020 orbiting the K-type main-sequence star HIP 65A, located approximately 202 light-years (62 parsecs) distant in the southern constellation of Phoenix. It completes one orbit around its host star every 23.5 hours (0.98 days), making it an ultra-short period planet. Its radius is likely smaller than 1.5 RJ—another estimate of 2.03+0.61
    −0.49      RJ     is likely an overestimate. [1]

    Contents

    Due to the planet's vicinity to the star, tidal interactions are slowly causing its orbit to decay. As such, the planet is expected to spiral into HIP 65A and be destroyed by its Roche limit within somewhere between 80 million years and a few billion years. [1]

    Physical properties

    HIP 65Ab is a massive super-Jupiter with a mass of about 3 MJ. Its unusually large radius of roughly 2 RJ is likely overestimated, caused by the grazing nature of its transit, that is to say the planet only partially transits the disc of the host star. This is also why the radius has such a large margin of error.

    It orbits extremely close to its star at a distance of 0.01782 AU (2,666,000 km), or about twice the radius of the Sun. As a result, the planet receives 661 times the flux Earth does, placing its equilibrium temperature at 1,411 K (1,138 °C; 2,080 °F), just above the melting point of copper. Based on the planet's mass and temperature, HIP 65Ab is unlikely to be larger than 1.5 RJ. [1] A 2024 study agrees with this, stating that the planet's true radius is close to the presented lower limit. [4]

    The characteristics of the massive planet and its 23.5-hour orbit make it a prime target for accurate atmospheric observations. [3] Its atmosphere was analysed spectroscopically for the first time in 2024, revealing absorption lines of water and carbon monoxide. Both molecules, however, are less abundant than they would be if the planet had a Sun-like composition. The results are consistent with the planet having a sub-solar metallicity but an overabundance of carbon and oxygen. This implies the planet may have formed beyond the snow line and migrated inward after the protoplanetary disk dissipated, or alternatively that some of the oxygen has precipitated out of the atmosphere. [4]

    Host star

    HIP 65A is a K-type main-sequence star with the spectral type K4V, which corresponds to its effective temperature of 4590±49  K (4,320 °C; 7,800 °F). This, combined with a radius of 0.7242 R☉, means that it radiates around 21% of the luminosity of the Sun from its photosphere. [1] The star has a mass of 0.74 M☉, [3] a rotation period of 13.2 days, and an age of 4.1+4.3
    −2.8     billion years. Despite its planet's low metallicity, the star itself is richer in heavy elements than the Sun with a metallicity of 0.18±0.08 dex.

    It is a planetary transit variable, dimming by about 8% each time the planet passes in front of the star. [1] This large transit depth, along with the star's high X-ray luminosity of 3.97+0.81
    −0.72     erg/cm -2 s -1 make HIP 65A one of the best candidates for transit observations using X-ray telescopes. [5]

    The star is part of a wide binary system with HIP 65B, an M-type red dwarf star which has a mass of 0.3 M☉ and an effective temperature of 3,861 K (3,588 °C; 6,490 °F). The two stars are separated by 3.95 arcseconds in the sky as seen from Earth, which corresponds to a distance of 269 AU. [1]

    Related Research Articles

    HD 109749 is a binary star system about 206 light years away in the constellation of Centaurus. The pair have a combined apparent visual magnitude of 8.08, which is too faint to be visible to the naked eye. The primary component has a close orbiting exoplanet companion. The system is drifting closer with a heliocentric radial velocity of −13.2 km/s.

    HD 118203 is a star with an orbiting exoplanet located in the northern circumpolar constellation of Ursa Major. It has the proper name Liesma, which means flame, and it is the name of a character from the Latvian poem Staburags un Liesma. The name was selected in the NameExoWorlds campaign by Latvia, during the 100th anniversary of the IAU.

    <span class="mw-page-title-main">Beta Pictoris b</span> Super Jupiter orbiting Beta Pictoris

    Beta Pictoris b (abbreviated as β Pic b) is an exoplanet orbiting the young debris disk A-type main sequence star Beta Pictoris located approximately 63 light-years (19.4 parsecs, or 6×1014 km) away from Earth in the constellation of Pictor. It has a mass around 13 Jupiter masses and a radius around 46% larger than Jupiter's. It orbits at 9 AU from Beta Pictoris, which is about 3.5 times farther than the orbit of Beta Pictoris c. It orbits close to the plane of the debris disk orbiting the star, with a low eccentricity and a period of 20–21 years.

    <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">K2-33b</span> Young Super-Neptune orbiting K2-33

    K2-33b is a very young super-Neptune exoplanet, orbiting the pre-main-sequence star K2-33. It was discovered by NASA's Kepler space telescope on its "Second Light" mission. It is located about 453 light-years away from Earth in the constellation of Scorpius. The exoplanet was found by using the transit method, in which the dimming effect that a planet causes as it crosses in front of its star is measured.

    HD 240237 b is a super-Jupiter exoplanet orbiting the K-type giant star HD 240237 about 4,900 light-years (1,500 parsecs, or nearly 4.6×1016 km) away from Earth in the constellation Cassiopeia. It orbits outside of the habitable zone of its star at a distance of 1.9 AU. The exoplanet was found by using the radial velocity method, from radial-velocity measurements via observation of Doppler shifts in the spectrum of the planet's parent star. The planet has a mildly eccentric orbit.

    HD 191806 is a star located in the northern constellation Cygnus. With an apparent magnitude of 8.093, it's undetectable with the naked eye, but can be seen with binoculars. HD 191806 is currently placed at a distance of 215 light years based on parallax measurements and is drifting towards the Solar System with a spectroscopic radial velocity of −15.28 km/s.

    <span class="mw-page-title-main">K2-146b</span>

    K2-146b is a Neptune-like exoplanet discovered in 2018 by the Kepler Space Telescope that orbits a low-mass M-type star in the constellation Cancer. Its host star, K2-146, is orbited by another planet named K2-146c. The planet orbits K2-146 at a distance of 0.0248 AU (3,710,000 km), fifteen times closer than Mercury is to the Sun. Thus, it orbits very rapidly, with one year lasting just 2.64 days, and is far too hot to be habitable, with an equilibrium temperature of 534 K.

    HATS-11b, also known as EPIC 216414930b, is a confirmed exoplanet, or exosolar planet, discovered in 2016 and has been described as similar to Jupiter. It orbits the star HATS-11.

    <span class="mw-page-title-main">V1298 Tauri</span> Star in the constellation Taurus

    V1298 Tauri is a young weakly-lined T Tauri star that is part of the Taurus-Auriga association in the Taurus Molecular Cloud. Alternatively it is part of a proposed moving group, called Group 29 that is slightly older. The system has four transiting exoplanets, discovered with the Kepler space telescope in the K2 mission. One of the planets was discovered in August 2019 and the other three were discovered in November 2019 by the same team.

    Qatar-3 is a 12th magnitude star located in the northern constellation Andromeda. It is host to a transiting planet. With a radial velocity of 10.99 km/s, it is drifting away from the Solar System, and is currently located 2,400 light years away based on its annual parallax.

    Qatar-4 is a faint K-dwarf star that hosts a planet in the constellation Andromeda. With an apparent magnitude of 13.60, it is impossible to detect with the naked eye, but can be detected with a powerful telescope. Qatar-4 is currently located 1,083 light years away based on parallax.

    Kepler-1704b is a super-Jupiter on a highly eccentric orbit around the star Kepler-1704. It has a mass of 4.51 MJ. The planet's distance from its star varies from 0.16 to 3.9 AU. It is a failed hot Jupiter, having been scattered from its birth orbit to orbit with a periastron just above the tidal circularization distance.

    HD 221420 is a likely binary star system in the southern circumpolar constellation Octans. It has an apparent magnitude of 5.81, allowing it to be faintly seen with the naked eye. The object is relatively close at a distance of 102 light years but is receding with a heliocentric radial velocity of 26.5 km/s.

    <span class="mw-page-title-main">TOI-2180 b</span> Jovian-sized exoplanet orbiting TOI-2180

    TOI-2180 b is a giant exoplanet orbiting the G-type star TOI-2180, also known as HD 238894. It was discovered with the help of the Transiting Exoplanet Survey Satellite and is currently the exoplanet with the longest orbital period TESS was able to uncover. TOI-2180 b orbits its host star every 260.16 days.

    WASP-178b, also known as KELT-26b and HD 134004 b, is an ultra-hot Jupiter exoplanet discovered in 2019 orbiting WASP-178, a hot A-type star located about 1,350 light-years away in the constellation of Lupus. At over 1.8 times the radius of Jupiter, it is among the largest exoplanets. The planet is tidally locked, heating up one side of the planet to such a degree that silicate rock and metal evaporate. Supersonic winds blow constantly towards the dark, cooler nighttime side, where the vaporized minerals condense and fall as rain.

    <span class="mw-page-title-main">WASP-178</span>

    WASP-178, also known as KELT-26 and HD 134004, is a star located about 1,350 light-years away in the southern constellation of Lupus. It is a hot A-type main sequence star or subgiant, a likely Am star, and a possible Delta Scuti variable, about twice as massive as the Sun and twenty times as luminous. In late 2019, the star was discovered to be orbited by an ultra-hot Jupiter planet, WASP-178b, making it one of the hottest stars known to host a hot Jupiter.

    <span class="mw-page-title-main">HD 11343</span> K-type giant star in the constellation Eridanus

    HD 11343 is a wide binary system between HD 11343 A, a K-type borderline giant star, and HD 11343 B, a red dwarf companion, located in the southern constellation of Eridanus about 500 light-years (150 pc) distant. Two gas giant exoplanets are known to orbit the primary star.

    References

    1. 1 2 3 4 5 6 7 8 9 10 11 Nielsen, L. D.; et al. (2020). "Three short-period Jupiters from TESS". Astronomy & Astrophysics. 639. EDP Sciences: A76. arXiv: 2003.05932 . doi: 10.1051/0004-6361/202037941 . ISSN   0004-6361.
    2. ↑ "CD-55 9423". SIMBAD . Centre de données astronomiques de Strasbourg . Retrieved 2024-10-22.
    3. 1 2 3 4 Paredes, Leonardo A.; et al. (2021-10-04). "The Solar Neighborhood XLVIII: Nine Giant Planets Orbiting Nearby K Dwarfs, and the CHIRON Spectrograph's Radial Velocity Performance". The Astronomical Journal. 162 (5). American Astronomical Society: 176. arXiv: 2111.15028 . Bibcode:2021AJ....162..176P. doi: 10.3847/1538-3881/ac082a . ISSN   0004-6256.
    4. 1 2 Bazinet, Luc; et al. (2024-04-09). "A Subsolar Metallicity on the Ultra-short-period Planet HIP 65Ab". The Astronomical Journal. 167 (5). American Astronomical Society: 206. arXiv: 2403.07983 . Bibcode:2024AJ....167..206B. doi: 10.3847/1538-3881/ad3071 . ISSN   0004-6256.
    5. ↑ Cilley, Raven; King, George W.; Corrales, Lia (2024). "Detecting exoplanet transits with the next generation of X-ray telescopes". The Astronomical Journal. 168 (4). American Astronomical Society: 177. arXiv: 2408.06417 . Bibcode:2024AJ....168..177C. doi: 10.3847/1538-3881/ad6d60 .
    This page is based on this Wikipedia article
    Text is available under the CC BY-SA 4.0 license; additional terms may apply.
    Images, videos and audio are available under their respective licenses.