KOI-4777.01
KOI-4777.01 is a terrestrial planet orbiting KOI-4777 in the constellation Lyra. It lies about 562 light-years from Earth and was discovered in 2022 using the transit method.
How Big Is KOI-4777.01?
KOI-4777.01 has a radius of 0.51 times that of Earth. Its mass is 99.2 times that of Earth.
Is KOI-4777.01 in the Habitable Zone?
KOI-4777.01 orbits inside the inner edge of the habitable zone of KOI-4777. So close to its star, surface conditions are far too hot for liquid water.
Habitable zone of KOI-4777: 0.121–0.314 AU (conservative: 0.153–0.298 AU), per Kopparapu et al. (2014). Earth orbits the Sun at 1 AU.
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Temperature on KOI-4777.01
The equilibrium temperature of KOI-4777.01 is about 1,180 K (907 °C) — hot enough to melt many metals. This estimate ignores any atmosphere, which could change surface temperatures dramatically — Earth's greenhouse effect adds about 33 °C. It receives 320 times the stellar energy that Earth gets from the Sun.
Orbit and Year Length
A year on KOI-4777.01 — one full orbit around KOI-4777 — lasts just 9.9 hours, shorter than Mercury's 88-day year. It orbits at an average distance of 0.008 AU — closer to its star than Mercury is to the Sun.
How Was KOI-4777.01 Discovered?
KOI-4777.01 was discovered in 2022 using the transit method, with observations from Kepler.
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 KOI-4777.01?
KOI-4777.01 is 561.8 light-years (172.2 parsecs) from Earth. Light arriving here tonight left the planet around the year 1465. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 9,887,680 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-4777.01 scores 0.26, ranking #2,857 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: KOI-4777
KOI-4777
- Surface temperature
- 3,515 K (Sun: 5,772 K)
- Mass
- 0.41 M☉
- Radius
- 0.40 R☉
- Age
- 4.0 billion years (Sun: 4.6)
Planetary System
KOI-4777.01 is the only planet known to orbit KOI-4777 so far.
KOI-4777.01 — Complete Data
| Radius | 0.510 Earth radii (0.045 Jupiter radii) |
|---|---|
| Mass | 99.20 Earth masses (0.312 Jupiter masses) |
| Orbital period | 0.41 days |
| Orbital distance | 0.008 AU |
| Equilibrium temperature | 1,180 K (907 °C) |
| Stellar irradiation | 320.00× Earth |
| Earth Similarity Index | 0.26 |
| Distance from Earth | 561.8 light-years (172.2 parsecs) |
| Constellation | Lyra |
| Discovery method | Transit |
| Discovery facility | Kepler |
| Discovery year | 2022 |
Data: NASA Exoplanet Archive, last updated 2022-01-10. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About KOI-4777.01
Is KOI-4777.01 habitable?
No — KOI-4777.01 orbits too close to its star and is too hot for liquid water to exist on its surface.
How far away is KOI-4777.01?
KOI-4777.01 is about 562 light-years from Earth in the constellation Lyra. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 9,887,680 years to get there.
How big is KOI-4777.01 compared to Earth?
KOI-4777.01 has 0.51 times the radius of Earth and about 99.2 times its mass.
How long is a year on KOI-4777.01?
One orbit around KOI-4777 takes 0.4 Earth days — short enough that 887 of its years would fit into one Earth year.
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