Astronomy:HIP 65426 b
 HIP 65426 b is on the lower left of the image, with the circle representing what Neptune's orbit would look like around the star HIP 65426, represented by a small cross. | |
| Discovery[2] | |
|---|---|
| Discovered by | SPHERE consortium[1] |
| Discovery date | 6 July 2017 |
| Direct imaging | |
| Designations | |
| Najsakopajk[3] | |
| Orbital characteristics | |
| 87+108 −31 au[4] | |
| Inclination | 100+15 −6 deg[4] |
| Physical characteristics | |
| Mean radius | Atmospheric model: 0.92±0.04 RJ[4] Evolutionary model: 1.45±0.03 RJ[4] |
| Mass | 7.1±1.1 MJ[4] |
| 4.07±0.19 dex | |
| Physics | Atmospheric model: 1667+25 −24 K[4] Evolutionary model: 1282+26 −31 K[4] |
HIP 65426 b, formally named Najsakopajk,[3] is a super-Jupiter exoplanet orbiting the star HIP 65426. It was discovered on 6 July 2017 by the SPHERE consortium using the Spectro-Polarimetric High-Contrast Exoplanet Research (SPHERE) instrument belonging to the European Southern Observatory (ESO).[6][7] It is 385 light-years from Earth.[8] It is the first planet discovered by ESO's SPHERE instrument.[9]
Nomenclature
In August 2022, this planet and its host star were included among 20 systems to be named by the third NameExoWorlds project.[10] The approved names, proposed by a team from Mexico, were announced in June 2023. HIP 65426 b is named Najsakopajk and its host star is named Matza, after Zoque words for "Mother Earth" and "star".[3]
Overview
The exoplanet HIP 65426 b orbits its host star HIP 65426, an A2V star with apparent magnitude 7.01 and a mass of 1.96±0.04 M☉.[11] This planetary system is located in the constellation Centaurus. The planet is around 14 million years old. However, it is not associated with a debris disk, despite its young age,[7][8] causing it to not fit current models for planetary formation.[12] It is around 92 AU from its parent star, with a possible dusty atmosphere.[13] It was discovered as part of the SHINE program, which aimed to find planetary systems around 600 new stars.[2]
In September 2022, HIP 65426 b became the first exoplanet directly observed by the James Webb Space Telescope.[14]
Planetary atmosphere
The spectrum taken in 2020 has indicated that HIP 65426 b is carbon-poor and oxygen-rich compared to Solar System gas giants.[5]
Spectral analysis of data from the James Webb Space Telescope revealed strong evidence of silicate clouds containing enstatite with no evidence of a dusty atmosphere.[15]
James Webb Space Telescope observation
In August 2022, a pre-print of the James Webb Space Telescope (JWST) observations was published. The JWST direct imaging observations between 2-16 μm of HIP 65426 b tightly constrained its bolometric luminosity to [math]\displaystyle{ \log(L_{bol}/L_{sun})=-4.23\plusmn0.02 }[/math], which provides a robust mass constraint of 7.1±1.1 MJ. The atmospheric fitting of both temperature and radius are in disagreement with evolutionary models. The team also constrained the semi-major axis and the inclination of the planet, but the new JWST astrometry of the planet did not significantly improve the orbit of the planet, especially the eccentricity remains unconstrained.[4]
HIP 65426 b is the first exoplanet to be imaged by JWST and the first exoplanet to be detected beyond 5 μm. The observations demonstrate that the James Webb Space Telescope will exceed its nominal predicted performance by a factor of 10 and that it will be able to image 0.3 |♃|J}}}}}} planets at 100 au for main-sequence stars, Neptune and Uranus-mass objects at 100-200 au for M-dwarfs and Saturn-mass objects at 10 au for M-dwarfs. For α Cen A JWST might be able to push the limit to a 5 R⊕ planet at 0.5 to 2.5 au.[4]
See also
References
- ↑ "Odd planetary system around fast-spinning star doesn't quite fit existing models of planet formation". https://sphere.osug.fr/spip.php?rubrique7.
- ↑ 2.0 2.1 Chauvin, G.; Desidera, S.; Lagrange, A. -M.; Vigan, A.; Gratton, R.; Langlois, M.; Bonnefoy, M.; Beuzit, J. -L. et al. (2017). "Discovery of a warm, dusty giant planet around HIP 65426". Astronomy and Astrophysics 605: L9. doi:10.1051/0004-6361/201731152. Bibcode: 2017A&A...605L...9C.
- ↑ 3.0 3.1 3.2 "2022 Approved Names". IAU. https://www.nameexoworlds.iau.org/2022approved-names.
- ↑ 4.0 4.1 4.2 4.3 4.4 4.5 4.6 4.7 4.8 Carter, Aarynn L.; Hinkley, Sasha; Kammerer, Jens; Skemer, Andrew; Biller, Beth A.; Leisenring, Jarron M.; Millar-Blanchaer, Maxwell A.; Petrus, Simon et al. (2023-07-06). "The JWST Early Release Science Program for Direct Observations of Exoplanetary Systems I: High Contrast Imaging of the Exoplanet HIP 65426 b from 2-16 μm". The Astrophysical Journal Letters 951 (1): L20. doi:10.3847/2041-8213/acd93e. Bibcode: 2023ApJ...951L..20C.
- ↑ 5.0 5.1 Petrus, S.; Bonnefoy, M.; Chauvin, G.; Charnay, B.; Marleau, G.-D.; Gratton, R.; Lagrange, A.-M.; Rameau, J. et al. (2021), "Medium-resolution spectrum of the exoplanet HIP 65426 B", Astronomy & Astrophysics 648: A59, doi:10.1051/0004-6361/202038914, Bibcode: 2021A&A...648A..59P
- ↑ "Scientists have found a planet that means everything they thought about planets isn't true" (in en). 2017-07-08. http://www.independent.co.uk/news/science/planets-hip-65426b-scientists-stars-solar-systems-sun-a7830556.html.
- ↑ 7.0 7.1 "Astronomers Directly Image Super-Jupiter around HIP 65426 | Astronomy | Sci-News.com" (in en-US). http://www.sci-news.com/astronomy/super-jupiter-hip-65426-05023.html.
- ↑ 8.0 8.1 "Holiday Special: Eight nights of Exoplanet Light". NASA. https://exoplanets.nasa.gov/news/1477/holiday-special-eight-nights-of-exoplanet-light/.
- ↑ "ESO's SPHERE Unveils its First Exoplanet" (in en-au). https://www.eso.org/public/announcements/ann17041/.
- ↑ "List of ExoWorlds 2022". IAU. 8 August 2022. https://www.nameexoworlds.iau.org/2022exoworlds.
- ↑ Template:Cite EPE
- ↑ "Odd planetary system around fast-spinning star doesn't quite fit existing models of planet formation" (in en-us). https://phys.org/news/2017-07-discovery-exoplanet-spherevlt.html.
- ↑ Johnson-Groh, Mara; July 12, 2017 (12 July 2017). "New exoplanet challenges formation models". https://astronomy.com/news/2017/07/fast-spinning-exoplanet-system-deeper.
- ↑ Fisher, Alise (2022-09-01). "NASA's Webb Takes Its First-Ever Direct Image of Distant World". NASA. https://blogs.nasa.gov/webb/2022/09/01/nasas-webb-takes-its-first-ever-direct-image-of-distant-world/?utm_source=TWITTER&utm_medium=NASAWebb&utm_campaign=NASASocial&linkId=179637235.
- ↑ Wang 王, Ji 吉 (2023-11-01). "Spectral Retrieval with JWST Photometric data: a Case Study for HIP 65426 b". The Astronomical Journal 166 (5): 203. doi:10.3847/1538-3881/acfca0. ISSN 0004-6256. Bibcode: 2023AJ....166..203W.
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