Key parameters at a glance

A radius of 2.46 Earth radii
A mass of 6.62 Earth masses
Surface gravity around 1.09 g
An orbital period of 15.530 days
Semi-major axis 0.0910 AU
Equilibrium temperature 379 K (106 °C)
Distance from Earth 26.61 light-years
Earth Similarity Index 0.631
Travel time at Voyager 1 speed 469,187 years
Almost certainly tidally locked to its host star given the close orbit

Gl 686 b Planet Profile

Physical Specs

Radius

2.46 R⊕

Radius (Jupiter)

0.220 R♃

Mass

6.62 M⊕

Mass (Jupiter)

0.021 M♃

Density

2.45 g/cm³

Surface Gravity

1.09 g (Earth)

Classification

Planet Type

Sub-Neptune

ESI Score 0.631

HZ Position Unknown

Controversial No

Discovery

Year 2018

Method Radial Velocity

Facility Roque de los Muchachos Observatory

Telescope 3.58 m Telescopio Nazionale Galileo

Size rank in cohort

Rank by radius

#1245of 1978

top 62.9%

This planet

2.46R⊕

Sub-Neptune median

2.71R⊕

Nearest-size peers

TOI-5800 b 2.46 R⊕ Kepler-282 d 2.46 R⊕ GJ 3341 b 2.46 R⊕

Metric	Earth	Gl 686 b	Jupiter
Radius (R⊕)	1.00	2.46	11.21
Mass (M⊕)	1.00	6.62	317.83
Density (g/cm³)	5.51	2.45	1.33
Surface Gravity (g)	1.00	1.09	2.53
Insolation (S⊕)	1.00	—	0.037

Alternative Mass Estimates

Method	Value	Interpretation
Minimum mass (M sin i)	6.624 M⊕	Lower bound from radial-velocity fitting.

Star Catalogue Identifiers

HIP

HIP 86287

TIC

TIC 230241767

Gaia DR2

Gaia DR2 4550763526539955712

Gaia DR3

Gaia DR3 4550763526539955712

System

Gl 686

Percentile among Sub-Neptune cohort

Radius 2.460 R⊕ · percentile 37 / cohort 1978

Mass 6.624 M⊕ · percentile 35 / cohort 1978

Orbital period 15.53 d · percentile 52 / cohort 1946

Distance 8.16 pc · percentile 1 / cohort 1975

ESI 0.631 · percentile 86 / cohort 1978

Orbit & Habitability

Orbital Dynamics

Period

15.530 days

Semi-major axis

0.0910 AU

Eccentricity

0.050

Inclination

— °

Year Length

A year here lasts approximately 15.53 Earth days (4.3% of a terrestrial year) on a nearly circular orbit at a mean orbital distance of 0.0910 AU.

Extended Orbital Architecture

RV semi-amplitude (K)

3.004 m/s

Transit mid-time (BJD)

2,450,606.8000

Long. of periastron (ω)

197.06°

Angular separation (arcsec)

11.20000

Eq. Temperature

379K

(106 °C)

Insolation (S⊕)

—

Earth = 1.00

Earth Similarity (ESI)

0.631

0 = alien, 1 = Earth-identical

Insufficient insolation data — the surface is too hot to retain surface water. Close-orbiting tidally-locked around a cool host.

Discovery Paper

Primary reference

Affer et al. 2019

Instrument

HARPS-N Spectrograph

Publication

2019-02

Observation locale

Ground

Discovery cohort

Planets confirmed in 2018 at Roque de los Muchachos Observatory (3 shown).

GJ 15 A c · Neptune-like HD 233832 b · Gas Giant HD 220197 b · Neptune-like

Host System: Gl 686

Spectral Class

M-type red dwarf

Effective Temperature

3,656 K — cooler than the Sun (5,778 K)

Estimated Age

—

Stellar Radius

0.427 R☉

Stellar Mass

0.426 M☉

Metallicity [Fe/H]

-0.23

Extended Stellar Properties

Surface gravity (log g)

4.870 dex

Stellar density

7.145 g/cm³

Systemic radial velocity

-10.09 km/s

Rotational v·sin i

2.49 km/s

Rotation period

38.73 days

Metallicity ratio

[Fe/H]

Distance

8.16 parsec

Light-years 26.61 ly

V-band magnitude

9.62 mag

Voyager-speed travel 469,187 yr

Multi-band Host Photometry — 8 bands

Astrometric Data

Parallax

122.561 mas

Total Proper Motion

1,352.212 mas/yr

PM Right Ascension

926.74 mas/yr

PM Declination

984.70 mas/yr

Galactic Cartesian (pc)

x = -0.091 · y = -0.943 · z = 0.319

Equatorial (J2000)

RA 264.47649° · Dec 18.59595°

Galactic ℓ, b

42.246° · 24.295°

Ecliptic λ, β

262.956° · 41.900°

HTM-20 index

-1244537734