Key parameters at a glance

A radius of 4.14 Earth radii
A mass of 16.00 Earth masses
Surface gravity around 0.93 g
An orbital period of 727.562 days
Semi-major axis 1.1650 AU
Distance from Earth 14.84 light-years
Earth Similarity Index 0.533
Travel time at Voyager 1 speed 261,670 years

1 sibling around GJ 687

GJ 687 c shares its host star with 1 other confirmed planet. Side-by-side measurements below.

Planet	Type	Radius (R⊕)	Mass (M⊕)	Period (d)	Eq. T (K)	Year
GJ 687 b	Neptune-like	4.32	17.20	38.142	—	2014
GJ 687 c this	Neptune-like	4.14	16.00	727.562	—	2020

GJ 687 c Planet Profile

Physical Specs

Radius

4.14 R⊕

Radius (Jupiter)

0.369 R♃

Mass

16.00 M⊕

Mass (Jupiter)

0.050 M♃

Density

1.24 g/cm³

Surface Gravity

0.93 g (Earth)

Classification

Planet Type

Neptune-like

ESI Score 0.533

HZ Position Unknown

Controversial No

Discovery

Year 2020

Method Radial Velocity

Facility Multiple Observatories

Telescope Multiple Telescopes

Size rank in cohort

Rank by radius

#535of 574

top 93.0%

This planet

4.14R⊕

Neptune-like median

6.39R⊕

Nearest-size peers

Kepler-1715 b 4.14 R⊕ TOI-1272 b 4.13 R⊕ Kepler-966 b 4.13 R⊕

Metric	Earth	GJ 687 c	Jupiter
Radius (R⊕)	1.00	4.14	11.21
Mass (M⊕)	1.00	16.00	317.83
Density (g/cm³)	5.51	1.24	1.33
Surface Gravity (g)	1.00	0.93	2.53
Insolation (S⊕)	1.00	—	0.037

Alternative Mass Estimates

Method	Value	Interpretation
Minimum mass (M sin i)	16.000 M⊕	Lower bound from radial-velocity fitting.

Star Catalogue Identifiers

HIP

HIP 86162

TIC

TIC 233193964

Gaia DR2

Gaia DR2 1637645127018395776

Gaia DR3

Gaia DR3 1637645127018395776

System

GJ 687

Percentile among Neptune-like cohort

Radius 4.140 R⊕ · percentile 7 / cohort 574

Mass 16.000 M⊕ · percentile 12 / cohort 574

Orbital period 727.56 d · percentile 97 / cohort 524

Distance 4.55 pc · percentile 0 / cohort 572

ESI 0.533 · percentile 97 / cohort 574

Orbit & Habitability

Orbital Dynamics

Period

727.562 days

Semi-major axis

1.1650 AU

Eccentricity

0.400

Inclination

— °

Year Length

A year here lasts about 1.99 Earth years on a highly eccentric trajectory at a mean orbital distance of 1.1650 AU.

Eq. Temperature

—

Insolation (S⊕)

—

Earth = 1.00

Earth Similarity (ESI)

0.533

0 = alien, 1 = Earth-identical

Discovery Paper

Primary reference

Feng et al. 2020

Instrument

Multiple Instruments

Publication

2020-10

Observation locale

Ground

Discovery cohort

Planets confirmed in 2020 at Multiple Observatories (12 shown).

GJ 3473 c · Sub-Neptune HIP 38594 b · Sub-Neptune HD 216520 c · Sub-Neptune HD 216520 b · Sub-Neptune HIP 107772 b · Sub-Neptune GJ 480 b · Sub-Neptune HIP 4845 b · Sub-Neptune HD 190007 b · Neptune-like GJ 2056 b · Neptune-like HD 238090 b · Sub-Neptune HIP 48714 b · Neptune-like HIP 38594 c · Neptune-like

Host System: GJ 687

Spectral Class

M-type red dwarf

Effective Temperature

3,413 K — cooler than the Sun (5,778 K)

Estimated Age

—

Stellar Radius

0.418 R☉

Stellar Mass

0.400 M☉

Metallicity [Fe/H]

0.06

Extended Stellar Properties

Surface gravity (log g)

4.859 dex

Stellar density

8.378 g/cm³

Systemic radial velocity

-28.80 km/s

Metallicity ratio

[Fe/H]

Distance

4.55 parsec

Light-years 14.84 ly

V-band magnitude

9.15 mag

Voyager-speed travel 261,670 yr

Multi-band Host Photometry — 12 bands

Astrometric Data

Parallax

219.781 mas

Total Proper Motion

1,309.394 mas/yr

PM Right Ascension

-320.64 mas/yr

PM Declination

-1,269.53 mas/yr

Galactic Cartesian (pc)

x = -0.038 · y = -0.367 · z = 0.929

Equatorial (J2000)

RA 264.10417° · Dec 68.33367°

Galactic ℓ, b

98.596° · 31.966°

Ecliptic λ, β

139.200° · 87.129°

HTM-20 index

1030525514

Observation Record

Photometric series

Stellar spectra

Archive notes