Key parameters at a glance

A radius of 13.70 Earth radii
A mass of 381.39 Earth masses
Surface gravity around 2.03 g
An orbital period of 5,681.000 days
Semi-major axis 6.1100 AU
Distance from Earth 106.83 light-years
Earth Similarity Index 0.323
Travel time at Voyager 1 speed 1,883,978 years

HD 100508 b Planet Profile

Physical Specs

Radius

13.70 R⊕

Radius (Jupiter)

1.220 R♃

Mass

381.39 M⊕

Mass (Jupiter)

1.200 M♃

Density

0.82 g/cm³

Surface Gravity

2.03 g (Earth)

Classification

Planet Type

Gas Giant

ESI Score 0.323

HZ Position Unknown

Controversial No

Discovery

Year 2026

Method Radial Velocity

Facility Las Campanas Observatory

Telescope 6.5 m Magellan II Clay Telescope

Size rank in cohort

Rank by radius

#554of 1771

top 31.2%

This planet

13.70R⊕

Gas Giant median

13.52R⊕

Nearest-size peers

HD 148164 b 13.70 R⊕ HD 114783 b 13.70 R⊕ HD 159243 b 13.70 R⊕

Metric	Earth	HD 100508 b	Jupiter
Radius (R⊕)	1.00	13.70	11.21
Mass (M⊕)	1.00	381.39	317.83
Density (g/cm³)	5.51	0.82	1.33
Surface Gravity (g)	1.00	2.03	2.53
Insolation (S⊕)	1.00	—	0.037

Alternative Mass Estimates

Method	Value	Interpretation
Best measured mass	381.394 M⊕	Direct mass measurement (not derived).
Minimum mass (M sin i)	324.185 M⊕	Lower bound from radial-velocity fitting.

Star Catalogue Identifiers

HD 100508

HIP

HIP 56363

TIC

TIC 280859200

Gaia DR2

Gaia DR2 5236623864770649600

Gaia DR3

Gaia DR3 5236623864770649600

System

HD 100508

Percentile among Gas Giant cohort

Radius 13.700 R⊕ · percentile 66 / cohort 1771

Mass 381.394 M⊕ · percentile 40 / cohort 1747

Orbital period 5,681.00 d · percentile 93 / cohort 1533

Distance 32.75 pc · percentile 9 / cohort 1759

ESI 0.323 · percentile 64 / cohort 1771

Orbit & Habitability

Orbital Dynamics

Period

5,681.000 days

Semi-major axis

6.1100 AU

Eccentricity

0.420

Inclination

62.00 °

Year Length

A year here lasts about 15.55 Earth years on a highly eccentric trajectory at a mean orbital distance of 6.1100 AU.

Eq. Temperature

—

Insolation (S⊕)

—

Earth = 1.00

Earth Similarity (ESI)

0.323

0 = alien, 1 = Earth-identical

Detection Signatures

Radial velocity

Stellar wobble has been measured spectroscopically.

Astrometry

Positional wobble of the host star was measured.

Discovery Paper

Primary reference

Wu et al. 2026

Instrument

Carnegie Planet Finder Spectrograph

Publication

2026-03

Observation locale

Ground

Discovery cohort

Planets confirmed in 2026 at Las Campanas Observatory (4 shown).

HD 68475 b · Gas Giant HD 48265 c · Gas Giant HD 164604 c · Gas Giant HD 114386 c · Gas Giant

Host System: HD 100508

Spectral Class

K-type orange

Effective Temperature

5,419 K — cooler than the Sun (5,778 K)

Estimated Age

—

Stellar Radius

1.018 R☉

Stellar Mass

0.940 M☉

Metallicity [Fe/H]

0.33

Extended Stellar Properties

Surface gravity (log g)

4.390 dex

Stellar density

1.257 g/cm³

Metallicity ratio

[Fe/H]

Distance

32.75 parsec

Light-years 106.83 ly

V-band magnitude

7.74 mag

Voyager-speed travel 1,883,978 yr

Multi-band Host Photometry — 11 bands

Astrometric Data

Parallax

30.501 mas

Total Proper Motion

284.317 mas/yr

PM Right Ascension

-284.02 mas/yr

PM Declination

-12.97 mas/yr

Galactic Cartesian (pc)

x = -0.387 · y = 0.045 · z = -0.921

Equatorial (J2000)

RA 173.30141° · Dec -67.05464°

Galactic ℓ, b

295.400° · -5.334°

Ecliptic λ, β

219.969° · -59.653°

HTM-20 index

307941048

Similar Worlds

BD+15 2940 b

Gas Giant · K-type orange

Radius 13.70 R⊕ · 1,390.8 ly

HD 116029 c

Gas Giant · K-type orange

Radius 13.70 R⊕ · 402.0 ly

HD 114783 b

Gas Giant · K-type orange

Radius 13.70 R⊕ · 68.7 ly

HD 208897 b

Gas Giant · K-type orange

Radius 13.70 R⊕ · 220.1 ly

HD 5608 b

Gas Giant · K-type orange

Radius 13.70 R⊕ · 189.5 ly

HD 130322 b

Gas Giant · K-type orange

Radius 13.70 R⊕ · 104.0 ly

Explore Related Categories

Gas Giant Planets Radial Velocity Discoveries Las Campanas Observatory Mission K-type orange Hosts