Key parameters at a glance

A radius of 1.07 Earth radii
A mass of 1.24 Earth masses
Surface gravity around 1.08 g
An orbital period of 3.887 days
Semi-major axis 0.0343 AU
Equilibrium temperature 571 K (298 °C)
Distance from Earth 579.23 light-years
Earth Similarity Index 0.565
Travel time at Voyager 1 speed 10,214,782 years
Almost certainly tidally locked to its host star given the close orbit

Context from the literature

Kepler-186b is an exoplanet located around 582 light-years away from Earth. Kepler-186b orbits a red dwarf known as Kepler-186, named after the space telescope that found it.

Excerpted from Wikipedia · full article

3 siblings around Kepler-186

Kepler-186 b shares its host star with 3 other confirmed planets. Side-by-side measurements below.

Planet	Type	Radius (R⊕)	Mass (M⊕)	Period (d)	Eq. T (K)	Year
Kepler-186 b this	Rocky Terrestrial	1.07	1.24	3.887	571	2014
Kepler-186 c	Super-Earth	1.25	2.10	7.267	464	2014
Kepler-186 d	Super-Earth	1.40	2.54	13.343	379	2014
Kepler-186 e	Super-Earth	1.27	2.15	22.408	319	2014

Kepler-186 b Planet Profile

Physical Specs

Radius

1.07 R⊕

Radius (Jupiter)

0.095 R♃

Mass

1.24 M⊕

Mass (Jupiter)

0.004 M♃

Density

5.56 g/cm³

Surface Gravity

1.08 g (Earth)

Classification

Planet Type

Rocky Terrestrial

ESI Score 0.565

HZ Position Inner

Controversial No

Discovery

Year 2014

Method Transit

Facility Kepler

Telescope 0.95 m Kepler Telescope

Size rank in cohort

Rank by radius

#262of 570

top 45.8%

This planet

1.07R⊕

Rocky Terrestrial median

1.01R⊕

Nearest-size peers

Kepler-1570 b 1.07 R⊕ Kepler-376 b 1.07 R⊕ Kepler-520 c 1.07 R⊕

Metric	Earth	Kepler-186 b	Jupiter
Radius (R⊕)	1.00	1.07	11.21
Mass (M⊕)	1.00	1.24	317.83
Density (g/cm³)	5.51	5.56	1.33
Surface Gravity (g)	1.00	1.08	2.53
Insolation (S⊕)	1.00	37.37	0.037

Star Catalogue Identifiers

TIC

TIC 268159861

Gaia DR2

Gaia DR2 2079000330051813504

Gaia DR3

Gaia DR3 2079000330051813504

System

Kepler-186

Percentile among Rocky Terrestrial cohort

Radius 1.070 R⊕ · percentile 53 / cohort 570

Mass 1.240 M⊕ · percentile 48 / cohort 570

Orbital period 3.89 d · percentile 43 / cohort 567

Distance 177.59 pc · percentile 30 / cohort 566

ESI 0.565 · percentile 75 / cohort 570

Orbit & Habitability

Orbital Dynamics

Period

3.887 days

Semi-major axis

0.0343 AU

Eccentricity

0.000

Inclination

89.60 °

Year Length

A year here lasts approximately 3.89 Earth days (1.1% of a terrestrial year) on a nearly circular orbit at a mean orbital distance of 0.0343 AU.

Transit Fingerprint

Depth

0.051 %

Duration

1.810 h

Impact parameter b

0.300

Rp / R★

0.020750

Transit midpoint (BJD)

2,454,966.3304

Photometric dip

Transit produces a flux drop of 514 ppm lasting ≈ 1.81 h.

Extended Orbital Architecture

Planet / star radius ratio

0.020750

Semi-major axis / stellar radius

16.715

Impact parameter (b)

0.300

Transit mid-time (BJD)

2,454,966.3304

Angular separation (arcsec)

0.19300

Eq. Temperature

571K

(298 °C)

Insolation (S⊕)

37.37

Earth = 1.00

Earth Similarity (ESI)

0.565

0 = alien, 1 = Earth-identical

Inside the inner HZ boundary (too hot for liquid water) — the surface is too hot to retain surface water. Close-orbiting tidally-locked around a cool host.

Discovery Paper

Primary reference

Rowe et al. 2014

Instrument

Kepler CCD Array

Publication

2014-03

Observation locale

Space

Discovery cohort

Planets confirmed in 2014 at Kepler (12 shown).

Kepler-186 e · Super-Earth Kepler-395 c · Super-Earth Kepler-220 e · Super-Earth Kepler-249 d · Super-Earth Kepler-296 f · Super-Earth Kepler-367 c · Rocky Terrestrial Kepler-296 e · Super-Earth Kepler-155 c · Sub-Neptune Kepler-138 d · Super-Earth Kepler-333 c · Rocky Terrestrial Kepler-331 d · Super-Earth Kepler-267 d · Sub-Neptune

Host System: Kepler-186

Spectral Class

M-type red dwarf

Effective Temperature

3,788 K — cooler than the Sun (5,778 K)

Estimated Age

4.00 Gyr — younger than the Sun (4.6 Gyr)

Stellar Radius

0.472 R☉

Stellar Mass

0.478 M☉

Metallicity [Fe/H]

-0.28

Extended Stellar Properties

Surface gravity (log g)

4.770 dex

Stellar density

6.400 g/cm³

Metallicity ratio

[M/H]

Distance

177.59 parsec

Light-years 579.23 ly

V-band magnitude

15.14 mag

Voyager-speed travel 10,214,782 yr

Multi-band Host Photometry — 16 bands

Astrometric Data

Parallax

5.602 mas

Total Proper Motion

4.839 mas/yr

PM Right Ascension

2.10 mas/yr

PM Declination

-4.36 mas/yr

Galactic Cartesian (pc)

x = 0.345 · y = -0.632 · z = 0.694

Equatorial (J2000)

RA 298.65274° · Dec 43.95499°

Galactic ℓ, b

78.520° · 8.171°

Ecliptic λ, β

318.672° · 62.636°

HTM-20 index

1990400524

Wikipedia →