KOI-984 c
KOI-984 c is a cold gas giant orbiting KOI-984 in the constellation Lyra. It lies about 824 light-years from Earth and was discovered in 2022 using the transit timing variations method.
Is KOI-984 c in the Habitable Zone?
KOI-984 c orbits inside the inner edge of the habitable zone of KOI-984. So close to its star, surface conditions are far too hot for liquid water.
Habitable zone of KOI-984: 0.530–1.267 AU (conservative: 0.671–1.202 AU), per Kopparapu et al. (2014). Earth orbits the Sun at 1 AU.
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Temperature on KOI-984 c
The equilibrium temperature of KOI-984 c is about 597 K (324 °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 KOI-984 c — one full orbit around KOI-984 — lasts 21.5 Earth days, shorter than Mercury's 88-day year. It orbits at an average distance of 0.147 AU — closer to its star than Mercury is to the Sun. Its orbit is highly elliptical (eccentricity 0.38), swinging dramatically closer to and farther from its star.
How Was KOI-984 c Discovered?
KOI-984 c was discovered in 2022 using the transit timing variations method, with observations from Kepler.
Transit timing variations reveal a planet through its gravitational tug on a sibling planet, which makes that sibling's transits arrive slightly early or late. The pattern of these deviations betrays the hidden planet's mass and orbit.
How Far Away Is KOI-984 c?
KOI-984 c is 824.1 light-years (252.7 parsecs) from Earth. Light arriving here tonight left the planet around the year 1202. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 14,504,160 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. KOI-984 c scores 0.11, ranking #4,395 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: KOI-984
KOI-984
- Surface temperature
- 5,295 K (Sun: 5,772 K)
- Mass
- 0.93 M☉
- Radius
- 0.82 R☉
The KOI-984 Planetary System
KOI-984 c is one of 2 known planets in the KOI-984 system. Its siblings:
- KOI-984 b (Neptune-like)
KOI-984 c — Complete Data
| Mass | 209.80 Earth masses (0.660 Jupiter masses) |
|---|---|
| Orbital period | 21.51 days |
| Orbital distance | 0.147 AU |
| Eccentricity | 0.380 |
| Equilibrium temperature | 597 K (324 °C) |
| Earth Similarity Index | 0.11 |
| Distance from Earth | 824.1 light-years (252.7 parsecs) |
| Constellation | Lyra |
| Discovery method | Transit Timing Variations |
| Discovery facility | Kepler |
| Discovery year | 2022 |
Data: NASA Exoplanet Archive, last updated 2022-07-12. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About KOI-984 c
Is KOI-984 c habitable?
No — KOI-984 c orbits too close to its star and is too hot for liquid water to exist on its surface.
How far away is KOI-984 c?
KOI-984 c is about 824 light-years from Earth in the constellation Lyra. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 14,504,160 years to get there.
How long is a year on KOI-984 c?
One orbit around KOI-984 takes 21.5 Earth days — short enough that 17 of its years would fit into one Earth year.
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