K2-315 b
confirmed planet • updated: 2020-08-06
K2-315 b orbits a small, cool red star called K2-315. Scientists found it using the transit method, which detects tiny dips in starlight when a planet crosses in front of its star.
This page summarizes a catalog entry. If a measurement is missing, it is not shown or guessed. Some values can differ slightly between studies; when that happens, we describe the range rather than picking a favorite without evidence.
Scientific context
Scientific context: This profile layers interpretation on top of archival measurements. Modeled bands appear where direct detections (like spectra or transits) are not listed.
What we can’t claim: surface conditions, biology, or breathable atmosphere without direct spectra.
The planet is about 95% the size of Earth and orbits its star every 3.14 days — a very short year. It receives about 7.5 times more starlight than Earth, making it quite hot. The star is much smaller and cooler than our Sun, which affects how we interpret the planet’s temperature and environment.
Glossary (plain English)
- AU: the average Earth–Sun distance.
- Semi-major axis: the planet’s average distance from its star.
- Eccentricity: how oval the orbit is (0 = circle).
- Radial velocity: finding a planet by measuring a star’s tiny “wobble.”
- m·sin i: a minimum mass estimate; the true mass can be higher if the orbit is tilted.
- Equilibrium temperature: a rough estimate from starlight alone, not a surface reading.
K2-315 b was first reported in 2020 using the Transit method. The discovery is linked to observations from K2.
In transit work, astronomers watch for tiny, repeating dips in a star’s light as the planet passes in front of it. Follow-up observations help rule out false positives and refine the orbit.
The catalog lists an orbital period of about 3.14 days.
Eccentricity is not provided here; many catalogs omit it when the solution is underconstrained.
A measured mass is not available in this row, which limits what we can infer about composition.
A catalog radius is also listed, which (together with mass) helps constrain density and interior structure.
Why “m·sin i” shows up on RV planets
K2-315 b orbits K2-315. The star is classified as M(3.5+/-0.5) V, which is a shorthand for temperature and color.
A temperature near 3300 K places it on the cool side of the main sequence. The system is about 185.8 light‑years away.
Several key parameters are not present in this single catalog row. Missing fields don’t mean the science is unknown—only that this particular snapshot doesn’t carry the values.
In this case the most noticeable gaps are: semi‑major axis, eccentricity, mass. As new observations arrive, archives often refresh these entries (and sometimes revise earlier numbers).
Scientists keep revisiting systems like this because each new instrument pass can tighten uncertainties: better timing improves the orbit, better spectra improves the star, and better follow‑up can confirm or refute competing solutions. Even when a planet is well‑established, refined stellar properties can shift the inferred planet size, temperature, and habitability context. Transit systems are especially valuable because they can be re‑observed for decades to detect subtle changes in timing or additional planets.