K2-99 c
K2-99 c is a cold gas giant orbiting K2-99 in the constellation Virgo. It lies about 1,694 light-years from Earth and was discovered in 2022 using the radial velocity method.
Is K2-99 c in the Habitable Zone?
K2-99 c orbits inside the inner edge of the habitable zone of K2-99. So close to its star, surface conditions are far too hot for liquid water.
Habitable zone of K2-99: 2.076–4.857 AU (conservative: 2.630–4.605 AU), per Kopparapu et al. (2014). Earth orbits the Sun at 1 AU.
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Temperature on K2-99 c
The equilibrium temperature of K2-99 c is about 390 K (117 °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.
Orbit and Year Length
A year on K2-99 c — one full orbit around K2-99 — lasts 522.2 Earth days, longer than an Earth year. It orbits at an average distance of 1.430 AU. Its orbit is mildly elliptical (eccentricity 0.21).
How Was K2-99 c Discovered?
K2-99 c was discovered in 2022 using the radial velocity method, with observations from Multiple Observatories.
The radial velocity method measures the subtle wobble of a star caused by the gravitational pull of an orbiting planet, visible as periodic shifts in the star's light spectrum. The size of the wobble reveals the planet's minimum mass.
How Far Away Is K2-99 c?
K2-99 c is 1,693.5 light-years (519.2 parsecs) from Earth. Light arriving here tonight left the planet about 1,694 years ago. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 29,805,600 years to make the journey.
The Host Star: K2-99
K2-99
- Surface temperature
- 6,069 K (Sun: 5,772 K)
- Mass
- 1.44 M☉
- Radius
- 2.55 R☉
- Luminosity
- 7.9299 L☉
- Age
- 3.7 billion years (Sun: 4.6)
The K2-99 Planetary System
K2-99 c is one of 2 known planets in the K2-99 system. Its siblings:
- K2-99 b (Hot Jupiter)
K2-99 c — Complete Data
| Mass (best estimate) | 2,669.76 Earth masses |
|---|---|
| Orbital period | 522.20 days |
| Orbital distance | 1.430 AU |
| Eccentricity | 0.210 |
| Equilibrium temperature | 390 K (117 °C) |
| Distance from Earth | 1,693.5 light-years (519.2 parsecs) |
| Constellation | Virgo |
| Discovery method | Radial Velocity |
| Discovery facility | Multiple Observatories |
| Discovery year | 2022 |
Data: NASA Exoplanet Archive, last updated 2025-02-24. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About K2-99 c
Is K2-99 c habitable?
No — K2-99 c orbits too close to its star and is too hot for liquid water to exist on its surface.
How far away is K2-99 c?
K2-99 c is about 1,694 light-years from Earth in the constellation Virgo. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 29,805,600 years to get there.
How long is a year on K2-99 c?
One orbit around K2-99 takes 522.2 Earth days.
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