Key parameters at a glance

A radius of 3.29 Earth radii
A mass of 10.80 Earth masses
Surface gravity around 1.00 g
An orbital period of 22.780 days
Distance from Earth 645.57 light-years
Earth Similarity Index 0.608
Travel time at Voyager 1 speed 11,384,575 years

1 sibling around K2-201

K2-201 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
K2-201 b	Super-Earth	1.40	2.54	1.060	—	2018
K2-201 c this	Sub-Neptune	3.29	10.80	22.780	—	2018

K2-201 c Planet Profile

Physical Specs

Radius

3.29 R⊕

Radius (Jupiter)

0.293 R♃

Mass

10.80 M⊕

Mass (Jupiter)

0.034 M♃

Density

1.67 g/cm³

Surface Gravity

1.00 g (Earth)

Classification

Planet Type

Sub-Neptune

ESI Score 0.608

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

#290of 1978

top 14.6%

This planet

3.29R⊕

Sub-Neptune median

2.71R⊕

Nearest-size peers

Kepler-724 b 3.29 R⊕ TOI-431 d 3.29 R⊕ Kepler-1999 b 3.29 R⊕

Metric	Earth	K2-201 c	Jupiter
Radius (R⊕)	1.00	3.29	11.21
Mass (M⊕)	1.00	10.80	317.83
Density (g/cm³)	5.51	1.67	1.33
Surface Gravity (g)	1.00	1.00	2.53
Insolation (S⊕)	1.00	—	0.037

Star Catalogue Identifiers

TIC

TIC 125060509

Gaia DR2

Gaia DR2 6771370981322320128

Gaia DR3

Gaia DR3 6771370981322320128

System

K2-201

Percentile among Sub-Neptune cohort

Radius 3.286 R⊕ · percentile 85 / cohort 1978

Mass 10.800 M⊕ · percentile 79 / cohort 1978

Orbital period 22.78 d · percentile 66 / cohort 1946

Distance 197.93 pc · percentile 29 / cohort 1975

ESI 0.608 · percentile 83 / cohort 1978

Orbit & Habitability

Orbital Dynamics

Period

22.780 days

Semi-major axis

— AU

Eccentricity

—

Inclination

89.27 °

Year Length

A year here lasts approximately 22.78 Earth days (6.2% of a terrestrial year).

Transit Fingerprint

Depth

0.125 %

Duration

3.648 h

Rp / R★

0.034302

Transit midpoint (BJD)

2,457,319.7830

Photometric dip

Transit produces a flux drop of 1,252 ppm lasting ≈ 3.65 h.

Eq. Temperature

—

Insolation (S⊕)

—

Earth = 1.00

Earth Similarity (ESI)

0.608

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: K2-201

Spectral Class

G-type yellow (Sun-like)

Effective Temperature

5,507 K — cooler than the Sun (5,778 K)

Estimated Age

—

Stellar Radius

0.878 R☉

Stellar Mass

0.956 M☉

Metallicity [Fe/H]

0.13

Extended Stellar Properties

Surface gravity (log g)

4.680 dex

Stellar density

1.873 g/cm³

Metallicity ratio

[Fe/H]

Distance

197.93 parsec

Light-years 645.57 ly

V-band magnitude

12.17 mag

Voyager-speed travel 11,384,575 yr

Multi-band Host Photometry — 12 bands

Astrometric Data

Parallax

5.024 mas

Total Proper Motion

41.000 mas/yr

PM Right Ascension

-2.97 mas/yr

PM Declination

-40.89 mas/yr

Galactic Cartesian (pc)

x = 0.368 · y = -0.843 · z = -0.393

Equatorial (J2000)

RA 293.56071° · Dec -23.13128°

Galactic ℓ, b

16.193° · -19.336°

Ecliptic λ, β

291.570° · -1.439°

HTM-20 index

-539274832