HD 155918 c
HD 155918 c is a cold gas giant orbiting HD 155918 in the constellation Apus. It lies about 90 light-years from Earth and was discovered in 2022 using the radial velocity method.
Is HD 155918 c in the Habitable Zone?
The position of HD 155918 c relative to the habitable zone of HD 155918 cannot be precisely determined from the available orbital data.
Orbit and Year Length
A year on HD 155918 c — one full orbit around HD 155918 — lasts 17,202.2 Earth days, longer than Jupiter's 12-year orbit. It orbits at an average distance of 13.183 AU. Its orbit is mildly elliptical (eccentricity 0.07).
How Was HD 155918 c Discovered?
HD 155918 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 HD 155918 c?
HD 155918 c is 89.9 light-years (27.6 parsecs) from Earth. Light arriving here tonight left the planet around the year 1937. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 1,582,240 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 155918 c scores 0.08, ranking #4,766 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: HD 155918
HD 155918
- Mass
- 1.03 M☉
The HD 155918 Planetary System
HD 155918 c is one of 2 known planets in the HD 155918 system. Its siblings:
- HD 155918 b (Super Earth)
HD 155918 c — Complete Data
| Mass | 1,878.05 Earth masses (5.909 Jupiter masses) |
|---|---|
| Orbital period | 17,202.19 days |
| Orbital distance | 13.183 AU |
| Eccentricity | 0.071 |
| Earth Similarity Index | 0.08 |
| Distance from Earth | 89.9 light-years (27.6 parsecs) |
| Constellation | Apus |
| Discovery method | Radial Velocity |
| Discovery facility | Multiple Observatories |
| Discovery year | 2022 |
Data: NASA Exoplanet Archive, last updated 2023-06-12. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About HD 155918 c
Is HD 155918 c habitable?
HD 155918 c is not known to orbit within the habitable zone of HD 155918, and as a cold gas giant it is an unlikely candidate for life as we know it.
How far away is HD 155918 c?
HD 155918 c is about 90 light-years from Earth in the constellation Apus. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 1,582,240 years to get there.
How long is a year on HD 155918 c?
One orbit around HD 155918 takes 17,202.2 Earth days.
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