Astronomy:TOI-157
TOI-157 (also known as TIC 140691463) is a G-type subgiant star[1] 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.[3][4]
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.[3] Using TESS data discrepant transit parameters as well as empirical limb-darkening coefficients could be determined.[5] 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.[6]
Age
It is a typical hot Jupiter.[1] However, at an age of 12.82+0.73
−1.4 billion years[1] 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.[7]
References
- ↑ 1.0 1.1 1.2 Nielsen, L. D. et al. (2020). "Three short-period Jupiters from TESS. HIP 65Ab, TOI-157b, and TOI-169b". Astronomy and Astrophysics 639. doi:10.1051/0004-6361/202037941. Bibcode: 2020A&A...639A..76N.
- ↑ 2.0 2.1 2.2 Vallenari, A. et al. (2022). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy & Astrophysics. doi:10.1051/0004-6361/202243940 Gaia DR3 record for this source at VizieR.
- ↑ 3.0 3.1 Martin, Pierre-Yves (2022). "Planet TOI-157 b" (in en). https://exoplanet.eu/catalog/toi_157_b--7320/.
- ↑ "TOI-157 | NASA Exoplanet Archive". https://exoplanetarchive.ipac.caltech.edu/overview/TOI-157.
- ↑ 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. doi:10.3847/1538-3881/ac5f55. ISSN 0004-6256. Bibcode: 2022AJ....163..228P.
- ↑ 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. doi:10.3847/2041-8213/ade794. ISSN 2041-8205. Bibcode: 2025ApJ...988L...4H.
- ↑ Lacki, Brian C.; Brzycki, Bryan; Croft, Steve; Czech, Daniel; DeBoer, David; DeMarines, Julia; Gajjar, Vishal; Isaacson, Howard et al. (2021-12-01). "One of Everything: The Breakthrough Listen Exotica Catalog". The Astrophysical Journal Supplement Series 257 (2): 42. doi:10.3847/1538-4365/ac168a. ISSN 0067-0049. Bibcode: 2021ApJS..257...42L.
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