Ross 508 b
Ross 508 b is a super-Earth orbiting the M4.5 V star Ross 508 in the constellation Serpens. It lies about 37 light-years from Earth and was discovered in 2022 using the radial velocity method. It orbits within the habitable zone of its star — the region where liquid water could exist on a planet's surface.
Is Ross 508 b in the Habitable Zone?
Ross 508 b orbits within the optimistic habitable zone of Ross 508 — the broader region where liquid water might be possible under favorable atmospheric conditions.
Habitable zone of Ross 508: 0.049–0.130 AU (conservative: 0.062–0.124 AU), per Kopparapu et al. (2014). Earth orbits the Sun at 1 AU.
See the full interactive habitable-zone view in the Exoplanet Explorer app ›
Orbit and Year Length
A year on Ross 508 b — one full orbit around Ross 508 — lasts 10.8 Earth days, shorter than Mercury's 88-day year. It orbits at an average distance of 0.054 AU — closer to its star than Mercury is to the Sun. Its orbit is highly elliptical (eccentricity 0.33), swinging dramatically closer to and farther from its star.
How Was Ross 508 b Discovered?
Ross 508 b was discovered in 2022 using the radial velocity method, with observations from Subaru Telescope.
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 Ross 508 b?
Ross 508 b is 36.6 light-years (11.2 parsecs) from Earth. Light arriving here tonight left the planet around the year 1990. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 644,160 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. Ross 508 b scores 0.77, ranking #32 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: Ross 508
Ross 508
- Spectral type
- M4.5 V
- Surface temperature
- 3,071 K (Sun: 5,772 K)
- Mass
- 0.18 M☉
- Radius
- 0.21 R☉
- Luminosity
- 0.0036 L☉
Planetary System
Ross 508 b is the only planet known to orbit Ross 508 so far.
Ross 508 b — Complete Data
| Mass (best estimate) | 4.00 Earth masses |
|---|---|
| Orbital period | 10.77 days |
| Orbital distance | 0.054 AU |
| Eccentricity | 0.330 |
| Earth Similarity Index | 0.77 |
| Distance from Earth | 36.6 light-years (11.2 parsecs) |
| Constellation | Serpens |
| Discovery method | Radial Velocity |
| Discovery facility | Subaru Telescope |
| Discovery year | 2022 |
Data: NASA Exoplanet Archive, last updated 2022-06-08. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About Ross 508 b
Is Ross 508 b habitable?
Ross 508 b orbits within the habitable zone of Ross 508, the region where liquid water could exist on a planet's surface. Whether it is actually habitable depends on its atmosphere and composition, which remain unknown.
How far away is Ross 508 b?
Ross 508 b is about 37 light-years from Earth in the constellation Serpens. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 644,160 years to get there.
How long is a year on Ross 508 b?
One orbit around Ross 508 takes 10.8 Earth days — short enough that 34 of its years would fit into one Earth year.
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