TOI-157
TOI-157 Credit: L. D. Nielsen | |
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Mensa[1] |
| Right ascension | 04h 54m 48.292s[2] |
| Declination | −76° 40′ 49.89″[2] |
| Characteristics | |
| Evolutionary stage | subgiant[3] |
| Spectral type | G9IV[3] |
| Astrometry | |
| Proper motion (μ) | RA: 11.849±0.013[2] mas/yr Dec.: −18.732±0.013[2] mas/yr |
| Parallax (π) | 2.8128±0.0105 mas[2] |
| Distance | 1,160 ± 4 ly (356 ± 1 pc) |
| Details | |
| Mass | 0.923[2] M☉ |
| Radius | 1.0977[2] R☉ |
| Luminosity | 1.106[2] L☉ |
| Surface gravity (log g) | 4.3027[2] cgs |
| Temperature | 5629[2] K |
| Age | 12.82+0.73 −1.40[3] Gyr |
| Other designations | |
| 2MASS J04544830-7640498, TIC 140691463, Gaia DR3 4624979393181971328 | |
| Database references | |
| SIMBAD | data |
TOI-157 (also known as TIC 140691463) is a G-type subgiant star[3] located about 1160 light years (356 pc) from Earth.[2] It has a mass of about 0.92 solar masses, a radius of about 1.1 solar radii and a temperature of about 5600 K.[2] It is approximately 12.0[2] to 12.8 billion years old.[4][5]
Planetary system
It has one discovered exoplanet orbiting it named TOI-157b. It is a gas giant classed as a hot Jupiter with a mass of 1.18 Jupiter masses and a radius of 1.286 Jupiter radii. It orbits very close to the star taking only 2 days to complete an orbit. This places the temperature of TOI-157b to be around 1588 Kelvin.[4] Using TESS data discrepant transit parameters as well as empirical limb-darkening coefficients could be determined.[6] Further analysis revealed that the radius ratio of planet to star is 7.8 ± 0.4 % higher than previously determined, caused by blending with the light from background stars, at a new value of 0.1229 ± 0.0005.[7]
Age
It is a typical hot Jupiter.[3] However, at an age of 12.82+0.73
−1.4 billion years[3] the planet is currently the oldest discovered and only about 1 billion years younger than the age of the universe at about 13.8 billion years and part of the list of exoplanet extremes. Only PSR B1620-26 b with 11.2–12.7 Gyr remains as alternatively oldest exoplanet.[8]
References
- ^ Roman, Nancy G. (1987). "Identification of a constellation from a position". Publications of the Astronomical Society of the Pacific. 99 (617): 695. Bibcode:1987PASP...99..695R. doi:10.1086/132034. Constellation record for this object at VizieR.
- ^ a b c d e f g h i j k l m Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv:2208.00211. Bibcode:2023A&A...674A...1G. doi:10.1051/0004-6361/202243940. S2CID 244398875. Gaia DR3 record for this source at VizieR.
- ^ a b c d e f Nielsen, L. D.; et al. (2020). "Three short-period Jupiters from TESS. HIP 65Ab, TOI-157b, and TOI-169b". Astronomy and Astrophysics. 639. arXiv:2003.05932. Bibcode:2020A&A...639A..76N. doi:10.1051/0004-6361/202037941.
- ^ a b Martin, Pierre-Yves (2022). "Planet TOI-157 b". exoplanet.eu. Retrieved 2025-06-15.
- ^ "TOI-157 | NASA Exoplanet Archive". exoplanetarchive.ipac.caltech.edu. Retrieved 2025-06-15.
- ^ Patel, Jayshil A.; Espinoza, Néstor (2022-05-01). "Empirical Limb-darkening Coefficients and Transit Parameters of Known Exoplanets from TESS". The Astronomical Journal. 163 (5): 228. arXiv:2203.05661. Bibcode:2022AJ....163..228P. doi:10.3847/1538-3881/ac5f55. ISSN 0004-6256.
- ^ Han, Te; Robertson, Paul; Brandt, Timothy D.; Kanodia, Shubham; Cañas, Caleb; Shporer, Avi; Ricker, George; Beard, Corey (2025-07-20). "Hundreds of TESS Exoplanets Might Be Larger than We Thought". The Astrophysical Journal Letters. 988 (1): L4. arXiv:2506.19985. Bibcode:2025ApJ...988L...4H. doi:10.3847/2041-8213/ade794. ISSN 2041-8205.
- ^ Lacki, Brian C.; Brzycki, Bryan; Croft, Steve; Czech, Daniel; DeBoer, David; DeMarines, Julia; Gajjar, Vishal; Isaacson, Howard; Lebofsky, Matt; MacMahon, David H. E.; Price, Danny C.; Sheikh, Sofia Z.; Siemion, Andrew P. V.; Drew, Jamie; Worden, S. Pete (2021-12-01). "One of Everything: The Breakthrough Listen Exotica Catalog". The Astrophysical Journal Supplement Series. 257 (2): 42. arXiv:2006.11304. Bibcode:2021ApJS..257...42L. doi:10.3847/1538-4365/ac168a. ISSN 0067-0049.