| Discovery | |
|---|---|
| Discovered by | Kepler (K2) |
| Discovery date | 2020 |
| Detection method | Transit |
| Orbital characteristics | |
| Semi-major axis | 0.02±0.00 AU |
| Orbital period (sidereal) | 3.14±0.00 d |
| Inclination | 88.7°±0.2° |
| Physical characteristics | |
| Mean radius | 0.95±0.06 R🜨 |
| Mass | 0.81 M🜨 |
| Temperature | 460 ± 5 K (368.33 ± 9.00 °F; 186.85 ± 5.00 °C) |
K2-315b is an exoplanet located 185.3 light years away from Earth in the southern zodiac constellation Libra. It orbits the red dwarf K2-315.
Discovery
K2-315b was discovered in 2020 by astronomers in an observatory using the Kepler space telescope. It is also nicknamed the "Pi Earth" because it takes approximately 3.14 days to orbit the host star.
Physical properties
The planet is thought to be a small rocky planet, even though composition is unknown. Since it orbits very close to its star, it is too hot to host life, due to it having a scorching temperature of 450 K. Not much is known about it because it was just discovered, but it is similar to Earth, having a radius 95% that of Earth, very similar to Venus, but has 81% Earth's mass.
Host star
 The location of K2-315 (circled in red) | |
| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
|---|---|
| Constellation | Libra |
| Right ascension | 15 12 05.1944 |
| Declination | −20° 06′ 30.5428″ |
| Apparent magnitude (V) | 17.67 |
| Characteristics | |
| Evolutionary stage | Red dwarf |
| Spectral type | M3.5±0.5 V |
| Astrometry | |
| Radial velocity (Rv) | 6.25±0.17 km/s |
| Proper motion (μ) | RA: −120.013 mas/yr Dec.: +74.471 mas/yr |
| Parallax (π) | 17.6353 ± 0.0492 mas |
| Distance | 184.9 ± 0.5 ly (56.7 ± 0.2 pc) |
| Details | |
| Mass | 0.174±0.004 M☉ |
| Radius | 0.2±0.01 R☉ |
| Luminosity | 0.398% L☉ |
| Surface gravity (log g) | 5.094±0.006 cgs |
| Temperature | 3,300±30 K |
| Metallicity | −0.24±0.09 dex |
| Rotational velocity (v sin i) | <5 km/s |
| Age | >1 Gyr |
| Other designations | |
| K2-315, EPIC 249631677 | |
| Database references | |
| SIMBAD | data |
K2-315 is a star in the southern zodiac constellation Libra. It has an apparent magnitude of 17.67, requiring a powerful telescope to be seen. The star is relatively close at a distance of 185 light years but is receding with a radial velocity of 6.25 km/s.
K2-315 has a stellar classification of M3.5±0.5 V, indicating that it is a M-type main-sequence star (with 14% uncertainty). It has 17.4% the mass of the Sun and 20% its radius. Typical for red dwarves, it has a luminosity less than 1% of the Sun, which yields an effective temperature of 3,300 K. Unlike most planetary hosts, K2-315 is metal-deficient, with an iron abundance only 57% that of the Sun. It is estimated to be over a billion years old, and has a projected rotational velocity less than 5 km/s.
References
- ^ Niraula, Prajwal; Julien de Wit; Rackham, Benjamin V.; Ducrot, Elsa; Burdanov, Artem; Crossfield, Ian J. M.; Valerie Van Grootel; Murray, Catriona; Garcia, Lionel J.; Alonso, Roi; Beard, Corey; Yilen Gomez Maqueo Chew; Delrez, Laetitia; Demory, Brice-Olivier; Fulton, Benjamin J.; Gillon, Michael; Gunther, Maximilian N.; Howard, Andrew W.; Issacson, Howard; Jehin, Emmanuel; Pedersen, Peter P.; Pozuelos, Francisco J.; Queloz, Didier; Rebolo-Lopez, Rafael; Sairam, Lalitha; Sebastian, Daniel; Thompson, Samantha; Triaud, Amaury H. M. J. (2020). "Π Earth: A 3.14 day Earth-sized Planet from K2's Kitchen Served Warm by the SPECULOOS Team". The Astronomical Journal. 160 (4): 172. arXiv:2006.07308. Bibcode:2020AJ....160..172N. doi:10.3847/1538-3881/aba95f. S2CID 219635862.
- ^ "Eyes On Exoplanets – Exoplanet Exploration: Planets Beyond our Solar System". exoplanets.nasa.gov. Retrieved 2021-08-08.
- "Exoplanet-catalog". Exoplanet Exploration: Planets Beyond our Solar System. NASA. Retrieved 2020-10-22.
- September 2020, Mike Wall 22 (22 September 2020). "'Pi planet' alien world takes 3.14 days to orbit its star". Space.com. Retrieved 2020-10-22.
{{cite web}}: CS1 maint: numeric names: authors list (link) - ^ Starr, Michelle (22 September 2020). "Astronomers Discover "Pi Earth" Exoplanet Orbits Its Star Once Every 3.14 Days". ScienceAlert. Retrieved 2020-10-21.
- "Exoplanet Archive". exoplanetarchive.ipac.caltech.edu. Retrieved 2020-10-21.
- "Find the constellation which contains given sky coordinates". djm.cc.
- ^ Brown, A. G. A.; et al. (Gaia collaboration) (2021). "Gaia Early Data Release 3: Summary of the contents and survey properties". Astronomy & Astrophysics. 649: A1. arXiv:2012.01533. Bibcode:2021A&A...649A...1G. doi:10.1051/0004-6361/202039657. S2CID 227254300. (Erratum: doi:10.1051/0004-6361/202039657e). Gaia EDR3 record for this source at VizieR.
- ^ Muirhead, Philip S.; Dressing, Courtney D.; Mann, Andrew W.; Rojas-Ayala, Bárbara; Lépine, Sébastien; Paegert, Martin; De Lee, Nathan; Oelkers, Ryan (4 April 2018). "A Catalog of Cool Dwarf Targets for the Transiting Exoplanet Survey Satellite". The Astronomical Journal. 155 (4): 180. arXiv:1710.00193. Bibcode:2018AJ....155..180M. doi:10.3847/1538-3881/aab710. eISSN 1538-3881.
- ^ Niraula, Prajwal; et al. (21 September 2020). "π Earth: A 3.14 day Earth-sized Planet from K2's Kitchen Served Warm by the SPECULOOS Team". The Astronomical Journal. 160 (4): 172. arXiv:2006.07308. Bibcode:2020AJ....160..172N. doi:10.3847/1538-3881/aba95f. eISSN 1538-3881. ISSN 0004-6256.
- "Odkryto "Ziemię Pi". Okrąża swoją gwiazdę raz na 3,14 dnia". www.national-geographic.pl.
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