Key parameters at a glance

A radius of 13.30 Earth radii
A mass of 759.61 Earth masses
Surface gravity around 4.29 g
An orbital period of 380.700 days
Semi-major axis 1.1900 AU
Distance from Earth 362.54 light-years
Earth Similarity Index 0.379
Travel time at Voyager 1 speed 6,393,370 years

HD 212771 b Planet Profile

Physical Specs

Radius

13.30 R⊕

Radius (Jupiter)

1.180 R♃

Mass

759.61 M⊕

Mass (Jupiter)

2.390 M♃

Density

1.77 g/cm³

Surface Gravity

4.29 g (Earth)

Classification

Planet Type

Gas Giant

ESI Score 0.379

HZ Position Unknown

Controversial No

Discovery

Year 2009

Method Radial Velocity

Facility W. M. Keck Observatory

Telescope 10 m Keck I Telescope

Size rank in cohort

Rank by radius

#793of 1771

top 44.7%

This planet

13.30R⊕

Gas Giant median

13.52R⊕

Nearest-size peers

HD 12661 b 13.30 R⊕ HD 129445 b 13.30 R⊕ GJ 876 b 13.30 R⊕

Metric	Earth	HD 212771 b	Jupiter
Radius (R⊕)	1.00	13.30	11.21
Mass (M⊕)	1.00	759.61	317.83
Density (g/cm³)	5.51	1.77	1.33
Surface Gravity (g)	1.00	4.29	2.53
Insolation (S⊕)	1.00	—	0.037

Alternative Mass Estimates

Method	Value	Interpretation
Minimum mass (M sin i)	759.614 M⊕	Lower bound from radial-velocity fitting.

Star Catalogue Identifiers

HD 212771

HIP

HIP 110813

TIC

TIC 12723961

Gaia DR2

Gaia DR2 2595360569884153728

Gaia DR3

Gaia DR3 2595360574179855104

System

HD 212771

Percentile among Gas Giant cohort

Radius 13.300 R⊕ · percentile 53 / cohort 1771

Mass 759.614 M⊕ · percentile 60 / cohort 1747

Orbital period 380.70 d · percentile 63 / cohort 1533

Distance 111.16 pc · percentile 37 / cohort 1759

ESI 0.379 · percentile 79 / cohort 1771

Orbit & Habitability

Orbital Dynamics

Period

380.700 days

Semi-major axis

1.1900 AU

Eccentricity

0.076

Inclination

— °

Year Length

A year here lasts about 1.04 Earth years on a nearly circular orbit at a mean orbital distance of 1.1900 AU.

Eq. Temperature

—

Insolation (S⊕)

—

Earth = 1.00

Earth Similarity (ESI)

0.379

0 = alien, 1 = Earth-identical

Discovery Paper

Primary reference

Johnson et al. 2010

Instrument

HIRES Spectrometer

Publication

2010-05

Observation locale

Ground

Discovery cohort

Planets confirmed in 2009 at W. M. Keck Observatory (12 shown).

HD 13931 b · Gas Giant HAT-P-13 c · Gas Giant HD 181342 b · Gas Giant HD 136418 b · Gas Giant HIP 79431 b · Gas Giant HD 206610 b · Gas Giant HD 4313 b · Gas Giant HD 180902 b · Gas Giant HD 95089 b · Gas Giant GJ 179 b · Gas Giant HD 34445 b · Gas Giant GJ 649 b · Gas Giant

Host System: HD 212771

Spectral Class

G-type yellow (Sun-like)

Effective Temperature

5,003 K — cooler than the Sun (5,778 K)

Estimated Age

6.00 Gyr — older than the Sun (4.6 Gyr)

Stellar Radius

5.270 R☉

Stellar Mass

1.560 M☉

Metallicity [Fe/H]

-0.21

Extended Stellar Properties

Surface gravity (log g)

3.310 dex

Systemic radial velocity

14.99 km/s

Rotational v·sin i

1.79 km/s

Metallicity ratio

[Fe/H]

Distance

111.16 parsec

Light-years 362.54 ly

V-band magnitude

7.60 mag

Voyager-speed travel 6,393,370 yr

Multi-band Host Photometry — 12 bands

Astrometric Data

Parallax

8.968 mas

Total Proper Motion

135.050 mas/yr

PM Right Ascension

-86.05 mas/yr

PM Declination

-104.08 mas/yr

Galactic Cartesian (pc)

x = 0.877 · y = -0.377 · z = -0.297

Equatorial (J2000)

RA 336.76241° · Dec -17.26410°

Galactic ℓ, b

41.794° · -55.291°

Ecliptic λ, β

332.141° · -7.032°

HTM-20 index

1454456850

Observation Record

Photometric series

RV measurements

Stellar spectra