Key parameters at a glance

A radius of 3.17 Earth radii
A mass of 10.20 Earth masses
Surface gravity around 1.01 g
An orbital period of 41.474 days
Distance from Earth 1,078.73 light-years
Earth Similarity Index 0.621
Travel time at Voyager 1 speed 19,023,316 years

K2-186 b Planet Profile

Physical Specs

Radius

3.17 R⊕

Radius (Jupiter)

0.283 R♃

Mass

10.20 M⊕

Mass (Jupiter)

0.032 M♃

Density

1.76 g/cm³

Surface Gravity

1.01 g (Earth)

Classification

Planet Type

Sub-Neptune

ESI Score 0.621

HZ Position Unknown

Controversial No

Discovery

Year 2018

Method Transit

Facility K2

Telescope 0.95 m Kepler Telescope

Size rank in cohort

Rank by radius

#377of 1978

top 19.0%

This planet

3.17R⊕

Sub-Neptune median

2.71R⊕

Nearest-size peers

K2-204 b 3.17 R⊕ Kepler-1727 b 3.17 R⊕ Kepler-253 d 3.17 R⊕

Metric	Earth	K2-186 b	Jupiter
Radius (R⊕)	1.00	3.17	11.21
Mass (M⊕)	1.00	10.20	317.83
Density (g/cm³)	5.51	1.76	1.33
Surface Gravity (g)	1.00	1.01	2.53
Insolation (S⊕)	1.00	—	0.037

Star Catalogue Identifiers

TIC

TIC 203228393

Gaia DR2

Gaia DR2 612404474610535936

Gaia DR3

Gaia DR3 612404474610535936

System

K2-186

Percentile among Sub-Neptune cohort

Radius 3.172 R⊕ · percentile 81 / cohort 1978

Mass 10.200 M⊕ · percentile 74 / cohort 1978

Orbital period 41.47 d · percentile 81 / cohort 1946

Distance 330.74 pc · percentile 37 / cohort 1975

ESI 0.621 · percentile 85 / cohort 1978

Orbit & Habitability

Orbital Dynamics

Period

41.474 days

Semi-major axis

— AU

Eccentricity

—

Inclination

89.52 °

Year Length

A year here lasts approximately 41.47 Earth days (11.4% of a terrestrial year).

Transit Fingerprint

Depth

0.098 %

Duration

6.120 h

Rp / R★

0.029650

Transit midpoint (BJD)

2,457,154.8454

Photometric dip

Transit produces a flux drop of 980 ppm lasting ≈ 6.12 h.

Eq. Temperature

—

Insolation (S⊕)

—

Earth = 1.00

Earth Similarity (ESI)

0.621

0 = alien, 1 = Earth-identical

Discovery Paper

Primary reference

Mayo et al. 2018

Instrument

Kepler CCD Array

Publication

2018-03

Observation locale

Space

Discovery cohort

Planets confirmed in 2018 at K2 (12 shown).

K2-190 c · Rocky Terrestrial K2-183 b · Rocky Terrestrial K2-209 b · Rocky Terrestrial K2-210 b · Rocky Terrestrial K2-165 b · Super-Earth K2-169 b · Super-Earth K2-148 b · Super-Earth K2-219 b · Super-Earth K2-190 b · Super-Earth K2-200 b · Super-Earth K2-201 b · Super-Earth K2-170 b · Super-Earth

Host System: K2-186

Spectral Class

G-type yellow (Sun-like)

Effective Temperature

5,784 K — hotter than the Sun (5,778 K)

Estimated Age

—

Stellar Radius

0.981 R☉

Stellar Mass

1.019 M☉

Metallicity [Fe/H]

0.06

Extended Stellar Properties

Surface gravity (log g)

4.450 dex

Stellar density

1.183 g/cm³

Systemic radial velocity

-13.70 km/s

Metallicity ratio

[Fe/H]

Distance

330.74 parsec

Light-years 1,078.73 ly

V-band magnitude

12.41 mag

Voyager-speed travel 19,023,316 yr

Multi-band Host Photometry — 17 bands

Astrometric Data

Parallax

2.995 mas

Total Proper Motion

37.571 mas/yr

PM Right Ascension

15.53 mas/yr

PM Declination

-34.21 mas/yr

Galactic Cartesian (pc)

x = -0.673 · y = 0.665 · z = 0.323

Equatorial (J2000)

RA 135.33505° · Dec 18.82529°

Galactic ℓ, b

208.960° · 36.830°

Ecliptic λ, β

132.335° · 1.799°

HTM-20 index

1351773846