Key parameters at a glance

A radius of 13.20 Earth radii
A mass of 889.92 Earth masses
Surface gravity around 5.11 g
An orbital period of 4,218.000 days
Semi-major axis 5.1500 AU
Distance from Earth 154.59 light-years
Earth Similarity Index 0.392
Travel time at Voyager 1 speed 2,726,122 years

HD 13931 b Planet Profile

Physical Specs

Radius

13.20 R⊕

Radius (Jupiter)

1.180 R♃

Mass

889.92 M⊕

Mass (Jupiter)

2.800 M♃

Density

2.13 g/cm³

Surface Gravity

5.11 g (Earth)

Classification

Planet Type

Gas Giant

ESI Score 0.392

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

#847of 1771

top 47.8%

This planet

13.20R⊕

Gas Giant median

13.52R⊕

Nearest-size peers

HD 12661 c 13.20 R⊕ HD 37605 b 13.20 R⊕ MOA-2009-BLG-387L b 13.20 R⊕

Metric	Earth	HD 13931 b	Jupiter
Radius (R⊕)	1.00	13.20	11.21
Mass (M⊕)	1.00	889.92	317.83
Density (g/cm³)	5.51	2.13	1.33
Surface Gravity (g)	1.00	5.11	2.53
Insolation (S⊕)	1.00	—	0.037

Alternative Mass Estimates

Method	Value	Interpretation
Best measured mass	889.920 M⊕	Direct mass measurement (not derived).
Minimum mass (M sin i)	699.226 M⊕	Lower bound from radial-velocity fitting.

Star Catalogue Identifiers

HD 13931

HIP

HIP 10626

TIC

TIC 292851928

Gaia DR2

Gaia DR2 351537889154226816

Gaia DR3

Gaia DR3 351537889154226816

System

HD 13931

Percentile among Gas Giant cohort

Radius 13.200 R⊕ · percentile 49 / cohort 1771

Mass 889.920 M⊕ · percentile 64 / cohort 1747

Orbital period 4,218.00 d · percentile 91 / cohort 1533

Distance 47.40 pc · percentile 18 / cohort 1759

ESI 0.392 · percentile 84 / cohort 1771

Orbit & Habitability

Orbital Dynamics

Period

4,218.000 days

Semi-major axis

5.1500 AU

Eccentricity

0.020

Inclination

43.00 °

Year Length

A year here lasts about 11.55 Earth years on a nearly circular orbit at a mean orbital distance of 5.1500 AU.

Extended Orbital Architecture

RV semi-amplitude (K)

23.300 m/s

Transit mid-time (BJD)

2,456,650.0000

Long. of periastron (ω)

-6.00°

Angular separation (arcsec)

109.00000

Eq. Temperature

—

Insolation (S⊕)

—

Earth = 1.00

Earth Similarity (ESI)

0.392

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

Howard et al. 2010

Instrument

HIRES Spectrometer

Publication

2010-10

Observation locale

Ground

Discovery cohort

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

HAT-P-13 c · Gas Giant HD 181342 b · Gas Giant HD 212771 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 13931

Spectral Class

G-type yellow (Sun-like)

Effective Temperature

5,867 K — hotter than the Sun (5,778 K)

Estimated Age

8.40 Gyr — older than the Sun (4.6 Gyr)

Stellar Radius

1.250 R☉

Stellar Mass

1.300 M☉

Metallicity [Fe/H]

0.05

Extended Stellar Properties

Surface gravity (log g)

4.360 dex

Stellar density

0.710 g/cm³

Systemic radial velocity

30.30 km/s

Rotational v·sin i

2.00 km/s

Activity index (log R'HK)

-5.030

Metallicity ratio

[Fe/H]

Distance

47.40 parsec

Light-years 154.59 ly

V-band magnitude

7.61 mag

Voyager-speed travel 2,726,122 yr

Multi-band Host Photometry — 11 bands

Astrometric Data

Parallax

21.070 mas

Total Proper Motion

208.516 mas/yr

PM Right Ascension

98.80 mas/yr

PM Declination

-183.63 mas/yr

Galactic Cartesian (pc)

x = 0.597 · y = 0.406 · z = 0.692

Equatorial (J2000)

RA 34.19800° · Dec 43.77221°

Galactic ℓ, b

138.832° · -16.449°

Ecliptic λ, β

47.310° · 28.247°

HTM-20 index

-348660612