HIP 4845 b
HIP 4845 b is a Neptune-like planet orbiting HIP 4845 in the constellation Cetus. It lies about 69 light-years from Earth and was discovered in 2020 using the radial velocity method.
Is HIP 4845 b in the Habitable Zone?
The position of HIP 4845 b relative to the habitable zone of HIP 4845 cannot be precisely determined from the available orbital data.
Orbit and Year Length
A year on HIP 4845 b — one full orbit around HIP 4845 — lasts 34.2 Earth days, shorter than Mercury's 88-day year. It orbits at an average distance of 0.176 AU — closer to its star than Mercury is to the Sun. Its orbit is mildly elliptical (eccentricity 0.25).
How Was HIP 4845 b Discovered?
HIP 4845 b was discovered in 2020 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 4845 b?
HIP 4845 b is 68.8 light-years (21.1 parsecs) from Earth. Light arriving here tonight left the planet around the year 1958. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 1,210,880 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. HIP 4845 b scores 0.45, ranking #342 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: HIP 4845
HIP 4845
- Mass
- 0.62 M☉
Planetary System
HIP 4845 b is the only planet known to orbit HIP 4845 so far.
HIP 4845 b — Complete Data
| Mass (best estimate) | 14.40 Earth masses |
|---|---|
| Orbital period | 34.15 days |
| Orbital distance | 0.176 AU |
| Eccentricity | 0.250 |
| Earth Similarity Index | 0.45 |
| Distance from Earth | 68.8 light-years (21.1 parsecs) |
| Constellation | Cetus |
| Discovery method | Radial Velocity |
| Discovery facility | Multiple Observatories |
| Discovery year | 2020 |
Data: NASA Exoplanet Archive, last updated 2020-09-08. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About HIP 4845 b
Is HIP 4845 b habitable?
HIP 4845 b is not known to orbit within the habitable zone of HIP 4845, and as a Neptune-like planet it is an unlikely candidate for life as we know it.
How far away is HIP 4845 b?
HIP 4845 b is about 69 light-years from Earth in the constellation Cetus. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 1,210,880 years to get there.
How long is a year on HIP 4845 b?
One orbit around HIP 4845 takes 34.2 Earth days — short enough that 11 of its years would fit into one Earth year.
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