Key parameters at a glance

A radius of 4.66 Earth radii
A mass of 19.60 Earth masses
Surface gravity around 0.90 g
An orbital period of 3.313 days
Equilibrium temperature 1,119 K (846 °C)
Distance from Earth 1,487.67 light-years
Earth Similarity Index 0.170
Travel time at Voyager 1 speed 26,235,046 years

K2-390 b Planet Profile

Physical Specs

Radius

4.66 R⊕

Radius (Jupiter)

0.416 R♃

Mass

19.60 M⊕

Mass (Jupiter)

0.062 M♃

Density

1.06 g/cm³

Surface Gravity

0.90 g (Earth)

Classification

Planet Type

Neptune-like

ESI Score 0.170

HZ Position Inner

Controversial No

Discovery

Year 2022

Method Transit

Facility K2

Telescope 0.95 m Kepler Telescope

Size rank in cohort

Rank by radius

#436of 574

top 75.8%

This planet

4.66R⊕

Neptune-like median

6.39R⊕

Nearest-size peers

Kepler-405 c 4.66 R⊕ TOI-942 c 4.67 R⊕ GJ 96 b 4.67 R⊕

Metric	Earth	K2-390 b	Jupiter
Radius (R⊕)	1.00	4.66	11.21
Mass (M⊕)	1.00	19.60	317.83
Density (g/cm³)	5.51	1.06	1.33
Surface Gravity (g)	1.00	0.90	2.53
Insolation (S⊕)	1.00	260.97	0.037

Star Catalogue Identifiers

TIC

TIC 9030119

Gaia DR2

Gaia DR2 2435650050614494336

Gaia DR3

Gaia DR3 2435650050614494336

System

K2-390

Percentile among Neptune-like cohort

Radius 4.662 R⊕ · percentile 24 / cohort 574

Mass 19.600 M⊕ · percentile 27 / cohort 574

Orbital period 3.31 d · percentile 6 / cohort 524

Distance 456.12 pc · percentile 55 / cohort 572

ESI 0.170 · percentile 20 / cohort 574

Orbit & Habitability

Orbital Dynamics

Period

3.313 days

Semi-major axis

— AU

Eccentricity

—

Inclination

— °

Year Length

A year here lasts approximately 3.31 Earth days (0.9% of a terrestrial year).

Transit Fingerprint

Depth

0.182 %

Duration

2.097 h

Impact parameter b

0.893

Rp / R★

0.044200

Transit midpoint (BJD)

2,457,739.9029

Photometric dip

Transit produces a flux drop of 1,815 ppm lasting ≈ 2.10 h.

Extended Orbital Architecture

Planet / star radius ratio

0.044200

Semi-major axis / stellar radius

5.510

Impact parameter (b)

0.893

Transit mid-time (BJD)

2,457,739.9029

Eq. Temperature

1,119K

(846 °C)

Insolation (S⊕)

260.97

Earth = 1.00

Earth Similarity (ESI)

0.170

0 = alien, 1 = Earth-identical

Inside the inner HZ boundary (too hot for liquid water) — the dayside is scorched.

Discovery Paper

Primary reference

Christiansen et al. 2022

Instrument

Kepler CCD Array

Publication

2022-03

Observation locale

Space

Discovery cohort

Planets confirmed in 2022 at K2 (12 shown).

K2-411 b · Rocky Terrestrial K2-381 b · Rocky Terrestrial K2-384 b · Rocky Terrestrial K2-400 b · Rocky Terrestrial K2-384 c · Rocky Terrestrial K2-369 b · Super-Earth K2-407 b · Super-Earth K2-414 b · Rocky Terrestrial K2-368 b · Super-Earth K2-413 c · Rocky Terrestrial K2-384 e · Super-Earth K2-407 c · Super-Earth

Host System: K2-390

Spectral Class

G-type yellow (Sun-like)

Effective Temperature

5,558 K — cooler than the Sun (5,778 K)

Estimated Age

—

Stellar Radius

0.966 R☉

Stellar Mass

0.789 M☉

Metallicity [Fe/H]

-0.12

Extended Stellar Properties

Surface gravity (log g)

4.368 dex

Stellar density

1.461 g/cm³

Metallicity ratio

[Fe/H]

Distance

456.12 parsec

Light-years 1,487.67 ly

V-band magnitude

13.61 mag

Voyager-speed travel 26,235,046 yr

Multi-band Host Photometry — 12 bands

Astrometric Data

Parallax

2.164 mas

Total Proper Motion

40.432 mas/yr

PM Right Ascension

26.67 mas/yr

PM Declination

-30.39 mas/yr

Galactic Cartesian (pc)

x = 0.983 · y = -0.074 · z = -0.167

Equatorial (J2000)

RA 355.70239° · Dec -9.58871°

Galactic ℓ, b

76.979° · -66.129°

Ecliptic λ, β

352.233° · -7.091°

HTM-20 index

-79550089