K2-315 b
K2-315 b is a terrestrial planet orbiting the M(3.5+/-0.5) V star K2-315 in the constellation Libra. It lies about 186 light-years from Earth and was discovered in 2020 using the transit method.
How Big Is K2-315 b?
K2-315 b has a radius of 0.95 times that of Earth.
Is K2-315 b in the Habitable Zone?
The position of K2-315 b relative to the habitable zone of K2-315 cannot be precisely determined from the available orbital data.
Habitable zone of K2-315: 0.052–0.138 AU (conservative: 0.066–0.130 AU), per Kopparapu et al. (2014). Earth orbits the Sun at 1 AU.
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Temperature on K2-315 b
The equilibrium temperature of K2-315 b is about 460 K (187 °C) — hotter than anywhere on Earth. This estimate ignores any atmosphere, which could change surface temperatures dramatically — Earth's greenhouse effect adds about 33 °C. It receives 7.45 times the stellar energy that Earth gets from the Sun.
Orbit and Year Length
A year on K2-315 b — one full orbit around K2-315 — lasts 3.14 Earth days, shorter than Mercury's 88-day year.
How Was K2-315 b Discovered?
K2-315 b was discovered in 2020 using the transit method, with observations from K2.
The transit method watches a star for the tiny, regular dip in brightness that occurs when a planet crosses in front of it. The depth and timing of these dips reveal the planet's size and orbital period.
How Far Away Is K2-315 b?
K2-315 b is 185.8 light-years (57.0 parsecs) from Earth. Light arriving here tonight left the planet around the year 1841. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 3,270,080 years to make the journey.
Earth Similarity Index
The Earth Similarity Index (ESI) scores how physically similar a planet is to Earth, from 0 to 1, based on radius, density, escape velocity and surface temperature. K2-315 b scores 0.46, ranking #319 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: K2-315
K2-315
- Spectral type
- M(3.5+/-0.5) V
- Surface temperature
- 3,300 K (Sun: 5,772 K)
- Mass
- 0.17 M☉
- Radius
- 0.20 R☉
- Luminosity
- 0.0041 L☉
- Age
- 1.0 billion years (Sun: 4.6)
Planetary System
K2-315 b is the only planet known to orbit K2-315 so far.
K2-315 b — Complete Data
| Radius | 0.950 Earth radii (0.085 Jupiter radii) |
|---|---|
| Orbital period | 3.14 days |
| Equilibrium temperature | 460 K (187 °C) |
| Stellar irradiation | 7.45× Earth |
| Earth Similarity Index | 0.46 |
| Distance from Earth | 185.8 light-years (57.0 parsecs) |
| Constellation | Libra |
| Discovery method | Transit |
| Discovery facility | K2 |
| Discovery year | 2020 |
Data: NASA Exoplanet Archive, last updated 2020-08-06. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About K2-315 b
Is K2-315 b habitable?
K2-315 b is not known to orbit within the habitable zone of K2-315, and as a terrestrial planet it is an unlikely candidate for life as we know it.
How far away is K2-315 b?
K2-315 b is about 186 light-years from Earth in the constellation Libra. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 3,270,080 years to get there.
How big is K2-315 b compared to Earth?
K2-315 b has 0.95 times the radius of Earth.
How long is a year on K2-315 b?
One orbit around K2-315 takes 3.1 Earth days — short enough that 116 of its years would fit into one Earth year.
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