K2-315b

K2-315b is an exoplanet located 185.3 light years away from Earth in the southern zodiac constellation Libra.^[2][3] It orbits the red dwarf K2-315.

K2-315b

Size comparison of the planet K2-315b (artistic concept) with Earth
Discovery[1]
Discovered by	Kepler (K2)
Discovery date	2020
Detection method	Transit
Orbital characteristics[1]
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🜨[1]
Temperature	460 ± 5 K (368.33 ± 9.00 °F; 186.85 ± 5.00 °C)[1]

Discovery

K2-315b was discovered in 2020 by astronomers in an observatory using the Kepler space telescope.^[1] It is also nicknamed the "Pi Planet" or "Pi Earth" because it takes approximately 3.14 days to orbit the host star.^[4][5][6]

Physical properties

The planet is thought to be a small rocky planet, even though composition is unknown.^[4] 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,^[7] very similar to Venus.

Host star

K2-315

The location of K2-315 (circled in red)
Observation data Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation	Libra[8]
Right ascension	15h 12m 05.1944s[9]
Declination	−20° 06′ 30.5428″[9]
Apparent magnitude (V)	17.67[10]
Characteristics
Evolutionary stage	Red dwarf
Spectral type	M3.5±0.5 V[11]
Astrometry
Radial velocity (Rv)	6.25±0.17[11] km/s
Proper motion (μ)	RA: −120.013 mas/yr[9] Dec.: +74.471 mas/yr[9]
Parallax (π)	17.6353±0.0492 mas[9]
Distance	184.9 ± 0.5 ly (56.7 ± 0.2 pc)
Details[11]
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 [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
SIMBAD	data

K2-315 is a star in the southern zodiac constellation Libra.^[12] It has an apparent magnitude of 17.67,^[10] requiring a powerful telescope to be seen. The star is relatively close at a distance of 185 light years^[9] but is receding with a radial velocity of 6.25 km/s.^[11]

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).^[11] It has 17.4% the mass of the Sun and 20% its radius.^[11] Typical for red dwarves, it has a luminosity less than 1% of the Sun, which yields an effective temperature of 3,300 K.^[11] Unlike most planetary hosts, K2-315 is metal-deficient, with an iron abundance only 57% that of the Sun.^[11] It is estimated to be over a billion years old, and has a projected rotational velocity less than 5 km/s.^[11]