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Ross 508 b

Ross 508 · M4.5 V host star · cool red dwarf · main sequence

[ ROSS_508_B.IMG ]
VIEW 1 · ON THE SURFACE
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Artist’s impression of Ross 508 b: VIEW 1 · ON THE SURFACE
VIEW 1 · ON THE SURFACE · Artist’s impression. No surface has been seen.
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36.6 light-years from Earth
[ FACTS.DAT ]
Right ascension / declination230.961° / 17.461°J2000 / ICRS
Gravity1.19 × Earthmodelled estimate
Year10.8 days
From its star0.0537 AUabout 8.0 million km
Stars in the system1 star1 known planet in system
Stars this world orbits1 starOrbits Ross 508
Day and nightLikely synchronous spinProbably spins once per orbit, keeping one hemisphere in permanent day and the other in permanent night. Heuristic: likely at ≤0.25 AU, uncertain to 0.50 AU, probably not beyond; rotation is not directly measured.
[ TEMP.EST ]MODELLED, NOT MEASURED
Host star≈3,200 Ktypical M4.5 V · 0.20 Sun radii
No atmosphere272 K · -1°C30% reflective · heat shared
Earth-like air305 K · 32°CBaseline plus 33°C

Star temperature and orbital distance set incoming energy, but stellar size is also required. This calculation uses a typical radius for the listed spectral type, 30% reflectivity and even heat redistribution. It is not a ground-temperature forecast: air, clouds, oceans and surface reflectivity could move the result by tens to hundreds of degrees. A likely synchronous spin also means the permanent day and night sides would not share one ground temperature.

[ STARLIGHT.SPC ]VISIBLE LIGHT ONLY

The marker above the bar is a typical temperature for this star’s class. The line below is Earth’s Sun.

red-orange

Ross 508 is class M4.5 V. Its visible daylight would be dim and strongly red-orange; most of its energy is infrared.

Representative lit-side geometry only. On a locked world, the star’s real elevation would depend on where you stand.

[ GROUND.TXT ]STILL INFERENCE

Most plausible case. The eccentric one. Average light is about 1.25 times Earth’s, but eccentricity 0.33 means the planet swings much closer and much farther, so the ground alternates between a hotter periastron and a colder apoapsis. The star spans about 2.1° at the average distance and looks larger still at closest approach. Ice would retreat at periastron and advance at apoapsis if any water is present.

Dry case. Bare rock that heats and cools through the ellipse. Dunes and dust on a world with no ocean to buffer the swing. Heat shimmer near closest approach.

Thick-air case. A thick atmosphere could smooth the periastron spike. It could also become steamy at closest approach and cloudy enough to hide the ground.

Walking. About 19% heavier than Earth, modelled. No known neighbor planet. The light is red, and the size of the star in the sky changes through the 11-day year. The system is 37 light-years away.

Based on: Harakawa et al. 2022; Teff 3071 K, R 0.21 Rsun, S 1.25, e 0.33, a 0.054 AU

[ ORBIT.SYS ]1 KNOWN · ALL SHOWN
100% · Above 30°

Ross 508 b circles Ross 508. Use Higher and Lower to move your viewpoint above, through and below the orbital plane, and − / + to zoom. Orbit shapes and spacing are schematic.

[ SOURCES.TXT ]

Positions, distances, and system parameters come from the NASA Exoplanet Archive composite table, queried 25 Sep 2026. GJ 273 b uses the parallax in that row, 12.4 light-years. The 45 worlds follow Bohl, Lawrence, Lowry, and Kaltenegger.