Key parameters at a glance

A mass of 3,464.33 Earth masses
An orbital period of 9,100.000 days
Semi-major axis 10.4000 AU
Equilibrium temperature 807 K (534 °C)
Distance from Earth 97.06 light-years
Travel time at Voyager 1 speed 1,711,580 years

51 Eri b Planet Profile

Physical Specs

Radius

— R⊕

Radius (Jupiter)

— R♃

Mass

3,464.33 M⊕

Mass (Jupiter)

10.900 M♃

Density

— g/cm³

Surface Gravity

— g (Earth)

Classification

Planet Type

Unclassified

ESI Score —

HZ Position Unknown

Controversial No

Discovery

Year 2015

Method Imaging

Facility Gemini Observatory

Telescope 8.19 m Gemini South Telescope

Metric	Earth	51 Eri b	Jupiter
Radius (R⊕)	1.00	—	11.21
Mass (M⊕)	1.00	3,464.33	317.83
Density (g/cm³)	5.51	—	1.33
Surface Gravity (g)	1.00	—	2.53
Insolation (S⊕)	1.00	—	0.037

Alternative Mass Estimates

Method	Value	Interpretation
Best measured mass	3,464.330 M⊕	Direct mass measurement (not derived).

Star Catalogue Identifiers

HD 29391

HIP

HIP 21547

TIC

TIC 298810162

Gaia DR2

Gaia DR2 3205095125321700480

Gaia DR3

Gaia DR3 3205095125321700480

System

51 Eri

Percentile among Unclassified cohort

Mass 3,464.330 M⊕ · percentile 86 / cohort 42

Orbital period 9,100.00 d · percentile 98 / cohort 43

Distance 29.76 pc · percentile 47 / cohort 43

Orbit & Habitability

Orbital Dynamics

Period

9,100.000 days

Semi-major axis

10.4000 AU

Eccentricity

0.570

Inclination

141.00 °

Year Length

A year here lasts about 24.91 Earth years on a highly eccentric trajectory at a mean orbital distance of 10.4000 AU.

Eq. Temperature

807K

(534 °C)

Insolation (S⊕)

—

Earth = 1.00

Earth Similarity (ESI)

—

0 = alien, 1 = Earth-identical

Insufficient insolation data — the surface is too hot to retain surface water.

Detection Signatures

Astrometry

Positional wobble of the host star was measured.

Direct imaging

The planet has been imaged directly (rare).

Discovery Paper

Primary reference

Macintosh et al. 2015

Instrument

Gemini Planet Imager

Publication

2015-00

Observation locale

Ground

Host System: 51 Eri

Spectral Class

F-type yellow-white

Effective Temperature

7,422 K — hotter than the Sun (5,778 K)

Estimated Age

0.02 Gyr — younger than the Sun (4.6 Gyr)

Stellar Radius

1.450 R☉

Stellar Mass

1.750 M☉

Metallicity [Fe/H]

0.13

Extended Stellar Properties

Surface gravity (log g)

4.311 dex

Stellar density

0.707 g/cm³

Systemic radial velocity

17.30 km/s

Rotational v·sin i

65.19 km/s

Metallicity ratio

[Fe/H]

Distance

29.76 parsec

Light-years 97.06 ly

V-band magnitude

5.21 mag

Voyager-speed travel 1,711,580 yr

Multi-band Host Photometry — 12 bands

Astrometric Data

Parallax

33.577 mas

Total Proper Motion

77.729 mas/yr

PM Right Ascension

44.35 mas/yr

PM Declination

-63.83 mas/yr

Galactic Cartesian (pc)

x = 0.352 · y = 0.935 · z = -0.043

Equatorial (J2000)

RA 69.40074° · Dec -2.47382°

Galactic ℓ, b

198.613° · -30.658°

Ecliptic λ, β

67.310° · -24.305°

HTM-20 index

781026835

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