Key parameters at a glance

A radius of 1.08 Earth radii
A mass of 1.26 Earth masses
Surface gravity around 1.09 g
An orbital period of 7.939 days
Distance from Earth 475.21 light-years
Earth Similarity Index 0.982
Travel time at Voyager 1 speed 8,380,373 years
Almost certainly tidally locked to its host star given the close orbit

2 siblings around K2-381

K2-381 b shares its host star with 2 other confirmed planets. Side-by-side measurements below.

Planet	Type	Radius (R⊕)	Mass (M⊕)	Period (d)	Eq. T (K)	Year
K2-381 b this	Rocky Terrestrial	1.08	1.26	7.939	—	2022
K2-381 c	Sub-Neptune	2.00	4.66	16.035	—	2022
K2-381 d	Super-Earth	1.69	3.50	26.803	—	2022

K2-381 b Planet Profile

Physical Specs

Radius

1.08 R⊕

Radius (Jupiter)

0.096 R♃

Mass

1.26 M⊕

Mass (Jupiter)

0.004 M♃

Density

5.57 g/cm³

Surface Gravity

1.09 g (Earth)

Classification

Planet Type

Rocky Terrestrial

ESI Score 0.982

HZ Position Unknown

Controversial No

Discovery

Year 2022

Method Transit

Facility K2

Telescope 0.95 m Kepler Telescope

Size rank in cohort

Rank by radius

#258of 570

top 45.1%

This planet

1.08R⊕

Rocky Terrestrial median

1.01R⊕

Nearest-size peers

K2-384 b 1.08 R⊕ Kepler-1698 b 1.07 R⊕ HD 63433 d 1.07 R⊕

Metric	Earth	K2-381 b	Jupiter
Radius (R⊕)	1.00	1.08	11.21
Mass (M⊕)	1.00	1.26	317.83
Density (g/cm³)	5.51	5.57	1.33
Surface Gravity (g)	1.00	1.09	2.53
Insolation (S⊕)	1.00	—	0.037

Star Catalogue Identifiers

TIC

TIC 10195089

Gaia DR2

Gaia DR2 4081376064109034496

Gaia DR3

Gaia DR3 4081376064109034496

System

K2-381

Percentile among Rocky Terrestrial cohort

Radius 1.075 R⊕ · percentile 55 / cohort 570

Mass 1.260 M⊕ · percentile 49 / cohort 570

Orbital period 7.94 d · percentile 73 / cohort 567

Distance 145.70 pc · percentile 27 / cohort 566

ESI 0.982 · percentile 97 / cohort 570

Orbit & Habitability

Orbital Dynamics

Period

7.939 days

Semi-major axis

— AU

Eccentricity

—

Inclination

88.86 °

Year Length

A year here lasts approximately 7.94 Earth days (2.2% of a terrestrial year).

Transit Fingerprint

Depth

0.021 %

Duration

1.464 h

Impact parameter b

0.505

Rp / R★

0.014600

Transit midpoint (BJD)

2,457,304.8440

Photometric dip

Transit produces a flux drop of 209 ppm lasting ≈ 1.46 h.

Extended Orbital Architecture

Planet / star radius ratio

0.014600

Semi-major axis / stellar radius

31.050

Impact parameter (b)

0.505

Transit mid-time (BJD)

2,457,304.8440

Eq. Temperature

—

Insolation (S⊕)

—

Earth = 1.00

Earth Similarity (ESI)

0.982

0 = alien, 1 = Earth-identical

Insufficient insolation data. Close-orbiting tidally-locked around a cool host.

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 K2-384 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 K2-368 c · Super-Earth

Host System: K2-381

Spectral Class

K-type orange

Effective Temperature

4,473 K — cooler than the Sun (5,778 K)

Estimated Age

—

Stellar Radius

0.675 R☉

Stellar Mass

0.754 M☉

Metallicity [Fe/H]

-0.24

Extended Stellar Properties

Surface gravity (log g)

4.653 dex

Stellar density

3.243 g/cm³

Metallicity ratio

[Fe/H]

Distance

145.70 parsec

Light-years 475.21 ly

V-band magnitude

12.88 mag

Voyager-speed travel 8,380,373 yr

Multi-band Host Photometry — 12 bands

Astrometric Data

Parallax

6.835 mas

Total Proper Motion

37.644 mas/yr

PM Right Ascension

-34.80 mas/yr

PM Declination

14.35 mas/yr

Galactic Cartesian (pc)

x = 0.289 · y = -0.888 · z = -0.358

Equatorial (J2000)

RA 288.02676° · Dec -21.00758°

Galactic ℓ, b

16.131° · -13.786°

Ecliptic λ, β

286.793° · 1.387°

HTM-20 index

-1461627296