Key parameters at a glance

A radius of 1.83 Earth radii
A mass of 4.00 Earth masses
Surface gravity around 1.19 g
An orbital period of 10.770 days
Semi-major axis 0.0537 AU
Distance from Earth 36.56 light-years
Earth Similarity Index 0.818
Travel time at Voyager 1 speed 644,790 years
Almost certainly tidally locked to its host star given the close orbit

Ross 508 b Planet Profile

Physical Specs

Radius

1.83 R⊕

Radius (Jupiter)

0.163 R♃

Mass

4.00 M⊕

Mass (Jupiter)

0.013 M♃

Density

3.59 g/cm³

Surface Gravity

1.19 g (Earth)

Classification

Planet Type

Super-Earth

ESI Score 0.818

HZ Position Unknown

Controversial No

Discovery

Year 2022

Method Radial Velocity

Facility Subaru Telescope

Telescope 8.2 m Subaru Telescope

Size rank in cohort

Rank by radius

#221of 1176

top 18.7%

This planet

1.83R⊕

Super-Earth median

1.60R⊕

Nearest-size peers

WASP-47 e 1.83 R⊕ Kepler-110 b 1.83 R⊕ K2-316 c 1.83 R⊕

Metric	Earth	Ross 508 b	Jupiter
Radius (R⊕)	1.00	1.83	11.21
Mass (M⊕)	1.00	4.00	317.83
Density (g/cm³)	5.51	3.59	1.33
Surface Gravity (g)	1.00	1.19	2.53
Insolation (S⊕)	1.00	—	0.037

Alternative Mass Estimates

Method	Value	Interpretation
Minimum mass (M sin i)	4.000 M⊕	Lower bound from radial-velocity fitting.

Star Catalogue Identifiers

TIC

TIC 400019820

Gaia DR2

Gaia DR2 1208695640675619584

Gaia DR3

Gaia DR3 1208695640675619584

System

Ross 508

Percentile among Super-Earth cohort

Radius 1.830 R⊕ · percentile 80 / cohort 1176

Mass 4.000 M⊕ · percentile 73 / cohort 1176

Orbital period 10.77 d · percentile 66 / cohort 1164

Distance 11.21 pc · percentile 2 / cohort 1171

ESI 0.818 · percentile 91 / cohort 1176

Orbit & Habitability

Orbital Dynamics

Period

10.770 days

Semi-major axis

0.0537 AU

Eccentricity

0.330

Inclination

— °

Year Length

A year here lasts approximately 10.77 Earth days (2.9% of a terrestrial year) on a highly eccentric trajectory at a mean orbital distance of 0.0537 AU.

Eq. Temperature

—

Insolation (S⊕)

—

Earth = 1.00

Earth Similarity (ESI)

0.818

0 = alien, 1 = Earth-identical

Insufficient insolation data. Close-orbiting tidally-locked around a cool host.

Discovery Paper

Primary reference

Harakawa et al. 2022

Instrument

Infrared Doppler (IRD)

Publication

2022-05

Observation locale

Ground

Host System: Ross 508

Spectral Class

M-type red dwarf

Effective Temperature

3,071 K — cooler than the Sun (5,778 K)

Estimated Age

—

Stellar Radius

0.211 R☉

Stellar Mass

0.177 M☉

Metallicity [Fe/H]

-0.20

Extended Stellar Properties

Surface gravity (log g)

5.039 dex

Stellar density

26.500 g/cm³

Metallicity ratio

[Fe/H]

Distance

11.21 parsec

Light-years 36.56 ly

V-band magnitude

14.18 mag

Voyager-speed travel 644,790 yr

Multi-band Host Photometry — 6 bands

Astrometric Data

Parallax

89.175 mas

Total Proper Motion

1,318.406 mas/yr

PM Right Ascension

-392.17 mas/yr

PM Declination

-1,258.73 mas/yr

Galactic Cartesian (pc)

x = -0.601 · y = -0.741 · z = 0.300

Equatorial (J2000)

RA 230.96130° · Dec 17.46053°

Galactic ℓ, b

25.647° · 53.600°

Ecliptic λ, β

223.004° · 34.751°

HTM-20 index

-1198709016