Key parameters at a glance

A radius of 3.61 Earth radii
A mass of 12.70 Earth masses
Surface gravity around 0.97 g
An orbital period of 15.872 days
Semi-major axis 0.1409 AU
Equilibrium temperature 923 K (650 °C)
Distance from Earth 1,166.91 light-years
Earth Similarity Index 0.235
Travel time at Voyager 1 speed 20,578,535 years

K2-225 b Planet Profile

Physical Specs

Radius

3.61 R⊕

Radius (Jupiter)

0.322 R♃

Mass

12.70 M⊕

Mass (Jupiter)

0.040 M♃

Density

1.48 g/cm³

Surface Gravity

0.97 g (Earth)

Classification

Planet Type

Sub-Neptune

ESI Score 0.235

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

#137of 1978

top 6.9%

This planet

3.61R⊕

Sub-Neptune median

2.71R⊕

Nearest-size peers

Kepler-869 b 3.61 R⊕ Kepler-258 c 3.61 R⊕ HIP 35173 b 3.61 R⊕

Metric	Earth	K2-225 b	Jupiter
Radius (R⊕)	1.00	3.61	11.21
Mass (M⊕)	1.00	12.70	317.83
Density (g/cm³)	5.51	1.48	1.33
Surface Gravity (g)	1.00	0.97	2.53
Insolation (S⊕)	1.00	—	0.037

Star Catalogue Identifiers

TIC

TIC 98677125

Gaia DR2

Gaia DR2 3579573358218514944

Gaia DR3

Gaia DR3 3579573358218514944

System

K2-225

Percentile among Sub-Neptune cohort

Radius 3.609 R⊕ · percentile 93 / cohort 1978

Mass 12.700 M⊕ · percentile 86 / cohort 1978

Orbital period 15.87 d · percentile 53 / cohort 1946

Distance 357.78 pc · percentile 39 / cohort 1975

ESI 0.235 · percentile 13 / cohort 1978

Orbit & Habitability

Orbital Dynamics

Period

15.872 days

Semi-major axis

0.1409 AU

Eccentricity

0.230

Inclination

88.64 °

Year Length

A year here lasts approximately 15.87 Earth days (4.3% of a terrestrial year) on a mildly elliptical path at a mean orbital distance of 0.1409 AU.

Transit Fingerprint

Depth

0.038 %

Duration

6.192 h

Impact parameter b

0.380

Rp / R★

0.019420

Transit midpoint (BJD)

2,457,619.1111

Photometric dip

Transit produces a flux drop of 377 ppm lasting ≈ 6.19 h.

Extended Orbital Architecture

Planet / star radius ratio

0.019420

Semi-major axis / stellar radius

17.820

Impact parameter (b)

0.380

Transit mid-time (BJD)

2,457,619.1111

Long. of periastron (ω)

-160.00°

Angular separation (arcsec)

0.39400

Eq. Temperature

923K

(650 °C)

Insolation (S⊕)

—

Earth = 1.00

Earth Similarity (ESI)

0.235

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: K2-225

Spectral Class

G-type yellow (Sun-like)

Effective Temperature

5,520 K — cooler than the Sun (5,778 K)

Estimated Age

0.01 Gyr — younger than the Sun (4.6 Gyr)

Stellar Radius

1.700 R☉

Stellar Mass

1.482 M☉

Metallicity [Fe/H]

0.49

Extended Stellar Properties

Surface gravity (log g)

4.148 dex

Stellar density

0.425 g/cm³

Systemic radial velocity

42.10 km/s

Metallicity ratio

[Fe/H]

Distance

357.78 parsec

Light-years 1,166.91 ly

V-band magnitude

11.84 mag

Voyager-speed travel 20,578,535 yr

Multi-band Host Photometry — 12 bands

Astrometric Data

Parallax

2.767 mas

Total Proper Motion

38.943 mas/yr

PM Right Ascension

-38.04 mas/yr

PM Declination

-8.32 mas/yr

Galactic Cartesian (pc)

x = -0.980 · y = -0.112 · z = -0.167

Equatorial (J2000)

RA 186.54110° · Dec -9.62482°

Galactic ℓ, b

292.608° · 52.740°

Ecliptic λ, β

189.817° · -6.242°

HTM-20 index

2134959424