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 7.056 days
Semi-major axis 0.0738 AU
Equilibrium temperature 1,148 K (875 °C)
Distance from Earth 1,882.69 light-years
Earth Similarity Index 0.196
Travel time at Voyager 1 speed 33,201,176 years

K2-204 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 0.196

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

#376of 1978

top 19.0%

This planet

3.17R⊕

Sub-Neptune median

2.71R⊕

Nearest-size peers

K2-186 b 3.17 R⊕ Kepler-1727 b 3.17 R⊕ Kepler-253 d 3.17 R⊕

Metric	Earth	K2-204 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 248351386

Gaia DR2

Gaia DR2 2533185974768028032

Gaia DR3

Gaia DR3 2533185974768028032

System

K2-204

Percentile among Sub-Neptune cohort

Radius 3.172 R⊕ · percentile 81 / cohort 1978

Mass 10.200 M⊕ · percentile 74 / cohort 1978

Orbital period 7.06 d · percentile 22 / cohort 1946

Distance 577.24 pc · percentile 51 / cohort 1975

ESI 0.196 · percentile 6 / cohort 1978

Orbit & Habitability

Orbital Dynamics

Period

7.056 days

Semi-major axis

0.0738 AU

Eccentricity

0.280

Inclination

88.76 °

Year Length

A year here lasts approximately 7.06 Earth days (1.9% of a terrestrial year) on a mildly elliptical path at a mean orbital distance of 0.0738 AU.

Transit Fingerprint

Depth

0.054 %

Duration

4.570 h

Impact parameter b

0.270

Rp / R★

0.023190

Transit midpoint (BJD)

2,457,452.9550

Photometric dip

Transit produces a flux drop of 538 ppm lasting ≈ 4.57 h.

Extended Orbital Architecture

Planet / star radius ratio

0.023190

Semi-major axis / stellar radius

12.640

Impact parameter (b)

0.270

Transit mid-time (BJD)

2,457,452.9550

Long. of periastron (ω)

-88.00°

Angular separation (arcsec)

0.12800

Eq. Temperature

1,148K

(875 °C)

Insolation (S⊕)

—

Earth = 1.00

Earth Similarity (ESI)

0.196

0 = alien, 1 = Earth-identical

Insufficient insolation data — the dayside is scorched.

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: K2-204

Spectral Class

G-type yellow (Sun-like)

Effective Temperature

5,783 K — hotter than the Sun (5,778 K)

Estimated Age

6.50 Gyr — older than the Sun (4.6 Gyr)

Stellar Radius

1.253 R☉

Stellar Mass

1.076 M☉

Metallicity [Fe/H]

0.21

Extended Stellar Properties

Surface gravity (log g)

4.273 dex

Stellar density

0.770 g/cm³

Metallicity ratio

[Fe/H]

Distance

577.24 parsec

Light-years 1,882.69 ly

V-band magnitude

12.99 mag

Voyager-speed travel 33,201,176 yr

Multi-band Host Photometry — 12 bands

Astrometric Data

Parallax

1.704 mas

Total Proper Motion

30.614 mas/yr

PM Right Ascension

-3.66 mas/yr

PM Declination

-30.39 mas/yr

Galactic Cartesian (pc)

x = 0.954 · y = 0.299 · z = -0.009

Equatorial (J2000)

RA 17.38251° · Dec -0.51775°

Galactic ℓ, b

132.948° · -63.037°

Ecliptic λ, β

15.821° · -7.303°

HTM-20 index

1338704075