K2-315b

K2-315b
Discovery[1]
Discovered byKepler (K2)
Discovery date2020
Transit
Orbital characteristics[1]
0.02±0.00 AU
3.14±0.00 d
Inclination88.7°±0.2°
Physical characteristics
0.95±0.06 R🜨[1]
Mass0.81 M🜨[2]
Temperature460 ± 5 K (368.33 ± 9.00 °F; 186.85 ± 5.00 °C)[1]

K2-315b is an exoplanet located 185.3 light years away from Earth in the southern zodiac constellation Libra.[3][4] It orbits the red dwarf K2-315.

Discovery

K2-315b was discovered in 2020 by astronomers in an observatory using the Kepler space telescope.[1] It is also nicknamed the "Pi Earth" because it takes approximately 3.14 days to orbit the host star.[5]

Physical properties

The planet is thought to be a small rocky planet, even though composition is unknown.[5] 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,[6] very similar to Venus, but has 81% Earth's mass.[2]

Size comparison of the planet K2-315b (artistic concept) with Earth

Host star

K2-315
The location of K2-315 (circled in red)
The location of K2-315 (circled in red)
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Libra[7]
Right ascension 15h 12m 05.1944s[8]
Declination −20° 06′ 30.5428″[8]
Apparent magnitude (V) 17.67[9]
Characteristics
Evolutionary stage Red dwarf
Spectral type M3.5±0.5 V[10]
Astrometry
Radial velocity (Rv)6.25±0.17[10] km/s
Proper motion (μ) RA: −120.013 mas/yr[8]
Dec.: +74.471 mas/yr[8]
Parallax (π)17.6353 ± 0.0492 mas[8]
Distance184.9 ± 0.5 ly
(56.7 ± 0.2 pc)
Details[10]
Mass0.174±0.004 M☉
Radius0.2±0.01 R☉
Luminosity0.398% L☉
Surface gravity (log g)5.094±0.006 cgs
Temperature3,300±30 K
Metallicity [Fe/H]−0.24±0.09 dex
Rotational velocity (v sin i)<5 km/s
Age>1 Gyr
Other designations
K2-315, EPIC 249631677
Database references
SIMBADdata

K2-315 is a star in the southern zodiac constellation Libra.[11] It has an apparent magnitude of 17.67,[9] requiring a powerful telescope to be seen. The star is relatively close at a distance of 185 light years[8] but is receding with a radial velocity of 6.25 km/s.[10]

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).[10] It has 17.4% the mass of the Sun and 20% its radius.[10] Typical for red dwarves, it has a luminosity less than 1% of the Sun, which yields an effective temperature of 3,300 K.[10] Unlike most planetary hosts, K2-315 is metal-deficient, with an iron abundance only 57% that of the Sun.[10] It is estimated to be over a billion years old, and has a projected rotational velocity less than 5 km/s.[10]


References

  1. ^ a b c d e 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.
  2. ^ a b "Eyes On Exoplanets – Exoplanet Exploration: Planets Beyond our Solar System". exoplanets.nasa.gov. Retrieved 2021-08-08.
  3. ^ "Exoplanet-catalog". Exoplanet Exploration: Planets Beyond our Solar System. NASA. Retrieved 2020-10-22.
  4. ^ 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)
  5. ^ a b Starr, Michelle (22 September 2020). "Astronomers Discover "Pi Earth" Exoplanet Orbits Its Star Once Every 3.14 Days". ScienceAlert. Retrieved 2020-10-21.
  6. ^ "Exoplanet Archive". exoplanetarchive.ipac.caltech.edu. Retrieved 2020-10-21.
  7. ^ "Find the constellation which contains given sky coordinates". djm.cc.
  8. ^ a b c d e 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.
  9. ^ a b 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.
  10. ^ a b c d e f g h i 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.
  11. ^ "Odkryto "Ziemię Pi". Okrąża swoją gwiazdę raz na 3,14 dnia". www.national-geographic.pl.
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