Key parameters at a glance

A radius of 13.70 Earth radii
A mass of 397.29 Earth masses
Surface gravity around 2.12 g
An orbital period of 380.850 days
Semi-major axis 0.9500 AU
Distance from Earth 155.65 light-years
Earth Similarity Index 0.326
Travel time at Voyager 1 speed 2,744,873 years

HD 20868 b Planet Profile

Physical Specs

Radius

13.70 R⊕

Radius (Jupiter)

1.220 R♃

Mass

397.29 M⊕

Mass (Jupiter)

1.250 M♃

Density

0.85 g/cm³

Surface Gravity

2.12 g (Earth)

Classification

Planet Type

Gas Giant

ESI Score 0.326

HZ Position Unknown

Controversial No

Discovery

Year 2008

Method Radial Velocity

Facility La Silla Observatory

Telescope 3.6 m ESO 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 20868 b	Jupiter
Radius (R⊕)	1.00	13.70	11.21
Mass (M⊕)	1.00	397.29	317.83
Density (g/cm³)	5.51	0.85	1.33
Surface Gravity (g)	1.00	2.12	2.53
Insolation (S⊕)	1.00	—	0.037

Alternative Mass Estimates

Method	Value	Interpretation
Minimum mass (M sin i)	397.288 M⊕	Lower bound from radial-velocity fitting.

Star Catalogue Identifiers

HD 20868

HIP

HIP 15578

TIC

TIC 142851295

Gaia DR2

Gaia DR2 5053536074700031616

Gaia DR3

Gaia DR3 5053536074700031616

System

HD 20868

Percentile among Gas Giant cohort

Radius 13.700 R⊕ · percentile 66 / cohort 1771

Mass 397.288 M⊕ · percentile 42 / cohort 1747

Orbital period 380.85 d · percentile 63 / cohort 1533

Distance 47.72 pc · percentile 18 / cohort 1759

ESI 0.326 · percentile 65 / cohort 1771

Orbit & Habitability

Orbital Dynamics

Period

380.850 days

Semi-major axis

0.9500 AU

Eccentricity

0.750

Inclination

— °

Year Length

A year here lasts about 1.04 Earth years on a highly eccentric trajectory at a mean orbital distance of 0.9500 AU.

Eq. Temperature

—

Insolation (S⊕)

—

Earth = 1.00

Earth Similarity (ESI)

0.326

0 = alien, 1 = Earth-identical

Discovery Paper

Primary reference

Moutou et al. 2009

Instrument

HARPS Spectrograph

Publication

2009-03

Observation locale

Ground

Discovery cohort

Planets confirmed in 2008 at La Silla Observatory (12 shown).

HD 285968 b · Sub-Neptune HD 47186 b · Neptune-like HD 145377 b · Gas Giant BD-17 63 b · Gas Giant HD 73267 b · Gas Giant HD 153950 b · Gas Giant HD 181433 d · Gas Giant HD 60532 c · Gas Giant HD 45364 b · Neptune-like HD 60532 b · Gas Giant HD 45364 c · Gas Giant HD 47186 c · Gas Giant

Host System: HD 20868

Spectral Class

K-type orange

Effective Temperature

4,802 K — cooler than the Sun (5,778 K)

Estimated Age

4.50 Gyr — younger than the Sun (4.6 Gyr)

Stellar Radius

0.760 R☉

Stellar Mass

0.390 M☉

Metallicity [Fe/H]

0.05

Extended Stellar Properties

Surface gravity (log g)

4.260 dex

Stellar density

2.453 g/cm³

Systemic radial velocity

46.12 km/s

Rotational v·sin i

1.10 km/s

Metallicity ratio

[Fe/H]

Distance

47.72 parsec

Light-years 155.65 ly

V-band magnitude

9.92 mag

Voyager-speed travel 2,744,873 yr

Multi-band Host Photometry — 11 bands

Astrometric Data

Parallax

20.926 mas

Total Proper Motion

307.863 mas/yr

PM Right Ascension

292.47 mas/yr

PM Declination

96.14 mas/yr

Galactic Cartesian (pc)

x = 0.533 · y = 0.639 · z = -0.555

Equatorial (J2000)

RA 50.17941° · Dec -33.72969°

Galactic ℓ, b

233.838° · -57.334°

Ecliptic λ, β

34.433° · -49.777°

HTM-20 index

1327232667

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 100508 b

Gas Giant · K-type orange

Radius 13.70 R⊕ · 106.8 ly

HD 5608 b

Gas Giant · K-type orange

Radius 13.70 R⊕ · 189.5 ly

Explore Related Categories

Gas Giant Planets Radial Velocity Discoveries La Silla Observatory Mission K-type orange Hosts