HD 99492 c
HD 99492 c is a Neptune-like planet orbiting the K2 V star HD 99492 in the constellation Leo. It lies about 59 light-years from Earth and was discovered in 2023 using the radial velocity method.
Is HD 99492 c in the Habitable Zone?
The position of HD 99492 c relative to the habitable zone of HD 99492 cannot be precisely determined from the available orbital data.
Orbit and Year Length
A year on HD 99492 c — one full orbit around HD 99492 — lasts 95.2 Earth days, between the years of Mercury (88 days) and Earth (365 days). Its orbit is mildly elliptical (eccentricity 0.06).
How Was HD 99492 c Discovered?
HD 99492 c was discovered in 2023 using the radial velocity method, with observations from Roque de los Muchachos Observatory.
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 HD 99492 c?
HD 99492 c is 59.4 light-years (18.2 parsecs) from Earth. Light arriving here tonight left the planet around the year 1967. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 1,045,440 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. HD 99492 c scores 0.47, ranking #299 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: HD 99492
HD 99492 c belongs to a system of 2 stars; it orbits HD 99492.
HD 99492
- Spectral type
- K2 V
- Surface temperature
- 4,929 K (Sun: 5,772 K)
- Mass
- 0.85 M☉
The HD 99492 Planetary System
HD 99492 c is one of 2 known planets in the HD 99492 system. Its siblings:
- HD 99492 b (Neptune-like)
HD 99492 c — Complete Data
| Mass (best estimate) | 17.90 Earth masses |
|---|---|
| Orbital period | 95.23 days |
| Eccentricity | 0.063 |
| Earth Similarity Index | 0.47 |
| Distance from Earth | 59.4 light-years (18.2 parsecs) |
| Constellation | Leo |
| Discovery method | Radial Velocity |
| Discovery facility | Roque de los Muchachos Observatory |
| Discovery year | 2023 |
Data: NASA Exoplanet Archive, last updated 2023-09-19. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About HD 99492 c
Is HD 99492 c habitable?
HD 99492 c is not known to orbit within the habitable zone of HD 99492, and as a Neptune-like planet it is an unlikely candidate for life as we know it.
How far away is HD 99492 c?
HD 99492 c is about 59 light-years from Earth in the constellation Leo. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 1,045,440 years to get there.
How long is a year on HD 99492 c?
One orbit around HD 99492 takes 95.2 Earth days.
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