Key parameters at a glance

A radius of 1.15 Earth radii
A mass of 1.60 Earth masses
Surface gravity around 1.21 g
An orbital period of 10.616 days
Equilibrium temperature 809 K (536 °C)
Distance from Earth 875.26 light-years
Earth Similarity Index 0.394
Travel time at Voyager 1 speed 15,435,253 years

1 sibling around K2-185

K2-185 b 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
K2-185 b this	Rocky Terrestrial	1.15	1.60	10.616	809	2018
K2-185 c	Sub-Neptune	2.39	6.30	52.713	477	2018

K2-185 b Planet Profile

Physical Specs

Radius

1.15 R⊕

Radius (Jupiter)

0.103 R♃

Mass

1.60 M⊕

Mass (Jupiter)

0.005 M♃

Density

5.78 g/cm³

Surface Gravity

1.21 g (Earth)

Classification

Planet Type

Rocky Terrestrial

ESI Score 0.394

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

#160of 570

top 27.9%

This planet

1.15R⊕

Rocky Terrestrial median

1.01R⊕

Nearest-size peers

Kepler-339 c 1.15 R⊕ Kepler-1240 b 1.15 R⊕ Kepler-1468 c 1.15 R⊕

Metric	Earth	K2-185 b	Jupiter
Radius (R⊕)	1.00	1.15	11.21
Mass (M⊕)	1.00	1.60	317.83
Density (g/cm³)	5.51	5.78	1.33
Surface Gravity (g)	1.00	1.21	2.53
Insolation (S⊕)	1.00	—	0.037

Star Catalogue Identifiers

TIC

TIC 337607207

Gaia DR2

Gaia DR2 609508120464763264

Gaia DR3

Gaia DR3 609508120464763264

System

K2-185

Percentile among Rocky Terrestrial cohort

Radius 1.150 R⊕ · percentile 71 / cohort 570

Mass 1.600 M⊕ · percentile 65 / cohort 570

Orbital period 10.62 d · percentile 80 / cohort 567

Distance 268.36 pc · percentile 37 / cohort 566

ESI 0.394 · percentile 59 / cohort 570

Orbit & Habitability

Orbital Dynamics

Period

10.616 days

Semi-major axis

— AU

Eccentricity

—

Inclination

88.93 °

Year Length

A year here lasts approximately 10.62 Earth days (2.9% of a terrestrial year).

Transit Fingerprint

Depth

0.016 %

Duration

2.600 h

Impact parameter b

0.740

Rp / R★

0.011100

Transit midpoint (BJD)

2,457,144.7271

Photometric dip

Transit produces a flux drop of 162 ppm lasting ≈ 2.60 h.

Extended Orbital Architecture

Planet / star radius ratio

0.011100

Semi-major axis / stellar radius

21.500

Impact parameter (b)

0.740

Transit mid-time (BJD)

2,457,144.7271

Eq. Temperature

809K

(536 °C)

Insolation (S⊕)

—

Earth = 1.00

Earth Similarity (ESI)

0.394

0 = alien, 1 = Earth-identical

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

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: K2-185

Spectral Class

G-type yellow (Sun-like)

Effective Temperature

5,788 K — hotter than the Sun (5,778 K)

Estimated Age

—

Stellar Radius

0.940 R☉

Stellar Mass

0.960 M☉

Metallicity [Fe/H]

-0.10

Extended Stellar Properties

Surface gravity (log g)

4.480 dex

Stellar density

2.107 g/cm³

Systemic radial velocity

-7.04 km/s

Rotation period

17.35 days

Metallicity ratio

[Fe/H]

Distance

268.36 parsec

Light-years 875.26 ly

V-band magnitude

12.24 mag

Voyager-speed travel 15,435,253 yr

Multi-band Host Photometry — 17 bands

Astrometric Data

Parallax

3.698 mas

Total Proper Motion

24.199 mas/yr

PM Right Ascension

2.17 mas/yr

PM Declination

-24.10 mas/yr

Galactic Cartesian (pc)

x = -0.625 · y = 0.738 · z = 0.254

Equatorial (J2000)

RA 130.25966° · Dec 14.69022°

Galactic ℓ, b

211.417° · 30.785°

Ecliptic λ, β

128.773° · -3.495°

HTM-20 index

-36492891