HIP 111909 c
HIP 111909 c is a cold gas giant orbiting the K1 III star HIP 111909 in the constellation Grus. It lies about 287 light-years from Earth and was discovered in 2025 using the radial velocity method.
Is HIP 111909 c in the Habitable Zone?
HIP 111909 c orbits inside the inner edge of the habitable zone of HIP 111909. So close to its star, surface conditions are far too hot for liquid water.
Habitable zone of HIP 111909: 2.547–6.186 AU (conservative: 3.227–5.865 AU), per Kopparapu et al. (2014). Earth orbits the Sun at 1 AU.
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Orbit and Year Length
A year on HIP 111909 c — one full orbit around HIP 111909 — lasts 893.6 Earth days, longer than an Earth year. It orbits at an average distance of 1.970 AU.
How Was HIP 111909 c Discovered?
HIP 111909 c was discovered in 2025 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 HIP 111909 c?
HIP 111909 c is 287.3 light-years (88.1 parsecs) from Earth. Light arriving here tonight left the planet around the year 1739. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 5,056,480 years to make the journey.
The Host Star: HIP 111909
HIP 111909
- Spectral type
- K1 III
- Surface temperature
- 4,891 K (Sun: 5,772 K)
- Mass
- 1.28 M☉
- Radius
- 4.53 R☉
- Luminosity
- 10.4713 L☉
- Age
- 4.3 billion years (Sun: 4.6)
The HIP 111909 Planetary System
HIP 111909 c is one of 2 known planets in the HIP 111909 system. Its siblings:
- HIP 111909 b (Cold Gas Giant)
HIP 111909 c — Complete Data
| Mass (best estimate) | 257.44 Earth masses |
|---|---|
| Orbital period | 893.63 days |
| Orbital distance | 1.970 AU |
| Distance from Earth | 287.3 light-years (88.1 parsecs) |
| Constellation | Grus |
| Discovery method | Radial Velocity |
| Discovery facility | Multiple Observatories |
| Discovery year | 2025 |
Data: NASA Exoplanet Archive, last updated 2025-10-30. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About HIP 111909 c
Is HIP 111909 c habitable?
No — HIP 111909 c orbits too close to its star and is too hot for liquid water to exist on its surface.
How far away is HIP 111909 c?
HIP 111909 c is about 287 light-years from Earth in the constellation Grus. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 5,056,480 years to get there.
How long is a year on HIP 111909 c?
One orbit around HIP 111909 takes 893.6 Earth days.
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