Key parameters at a glance

A radius of 1.07 Earth radii
A mass of 1.23 Earth masses
Surface gravity around 1.08 g
An orbital period of 8.256 days
Semi-major axis 0.0836 AU
Equilibrium temperature 1,387 K (1114 °C)
Distance from Earth 871.89 light-years
Earth Similarity Index 0.223
Travel time at Voyager 1 speed 15,375,779 years

2 siblings around Kepler-381

Kepler-381 d 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
Kepler-381 b	Rocky Terrestrial	0.99	0.94	5.629	1,576	2014
Kepler-381 d this	Rocky Terrestrial	1.07	1.23	8.256	1,387	2021
Kepler-381 c	Rocky Terrestrial	1.12	1.46	13.392	1,180	2014

Kepler-381 d Planet Profile

Physical Specs

Radius

1.07 R⊕

Radius (Jupiter)

0.095 R♃

Mass

1.23 M⊕

Mass (Jupiter)

0.004 M♃

Density

5.57 g/cm³

Surface Gravity

1.08 g (Earth)

Classification

Planet Type

Rocky Terrestrial

ESI Score 0.223

HZ Position Inner

Controversial No

Discovery

Year 2021

Method Transit

Facility Kepler

Telescope 0.95 m Kepler Telescope

Size rank in cohort

Rank by radius

#269of 570

top 47.0%

This planet

1.07R⊕

Rocky Terrestrial median

1.01R⊕

Nearest-size peers

Kepler-1570 b 1.07 R⊕ Kepler-376 b 1.07 R⊕ Kepler-186 b 1.07 R⊕

Metric	Earth	Kepler-381 d	Jupiter
Radius (R⊕)	1.00	1.07	11.21
Mass (M⊕)	1.00	1.23	317.83
Density (g/cm³)	5.51	5.57	1.33
Surface Gravity (g)	1.00	1.08	2.53
Insolation (S⊕)	1.00	436.70	0.037

Star Catalogue Identifiers

TIC

TIC 164884235

Gaia DR2

Gaia DR2 2105835281411929728

Gaia DR3

Gaia DR3 2105835281411929728

System

Kepler-381

Percentile among Rocky Terrestrial cohort

Radius 1.067 R⊕ · percentile 53 / cohort 570

Mass 1.230 M⊕ · percentile 47 / cohort 570

Orbital period 8.26 d · percentile 74 / cohort 567

Distance 267.32 pc · percentile 37 / cohort 566

ESI 0.223 · percentile 18 / cohort 570

Orbit & Habitability

Orbital Dynamics

Period

8.256 days

Semi-major axis

0.0836 AU

Eccentricity

0.000

Inclination

87.44 °

Year Length

A year here lasts approximately 8.26 Earth days (2.3% of a terrestrial year) on a nearly circular orbit at a mean orbital distance of 0.0836 AU.

Transit Fingerprint

Depth

0.004 %

Duration

1.990 h

Impact parameter b

0.900

Rp / R★

0.005829

Transit midpoint (BJD)

2,454,970.9254

Photometric dip

Transit produces a flux drop of 40 ppm lasting ≈ 1.99 h.

Extended Orbital Architecture

Planet / star radius ratio

0.005829

Semi-major axis / stellar radius

12.800

Impact parameter (b)

0.900

Transit mid-time (BJD)

2,454,970.9254

Angular separation (arcsec)

0.31300

Eq. Temperature

1,387K

(1114 °C)

Insolation (S⊕)

436.70

Earth = 1.00

Earth Similarity (ESI)

0.223

0 = alien, 1 = Earth-identical

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

Discovery Paper

Primary reference

Valizadegan et al. 2022

Instrument

Kepler CCD Array

Publication

2022-02

Observation locale

Space

Discovery cohort

Planets confirmed in 2021 at Kepler (12 shown).

Kepler-1816 b · Super-Earth Kepler-1705 c · Sub-Neptune Kepler-1948 b · Rocky Terrestrial Kepler-196 d · Sub-Neptune Kepler-1853 b · Super-Earth Kepler-1840 b · Sub-Neptune Kepler-1881 b · Sub-Neptune Kepler-1858 b · Sub-Neptune Kepler-1874 b · Sub-Neptune Kepler-1802 c · Sub-Neptune Kepler-1749 b · Super-Earth Kepler-1849 b · Sub-Neptune

Host System: Kepler-381

Spectral Class

F-type yellow-white

Effective Temperature

6,197 K — hotter than the Sun (5,778 K)

Estimated Age

2.57 Gyr — younger than the Sun (4.6 Gyr)

Stellar Radius

2.188 R☉

Stellar Mass

1.198 M☉

Metallicity [Fe/H]

-0.32

Extended Stellar Properties

Surface gravity (log g)

3.837 dex

Stellar density

1.685 g/cm³

Systemic radial velocity

-2.03 km/s

Metallicity ratio

[Fe/H]

Distance

267.32 parsec

Light-years 871.89 ly

V-band magnitude

10.47 mag

Voyager-speed travel 15,375,779 yr

Multi-band Host Photometry — 14 bands

Astrometric Data

Parallax

3.712 mas

Total Proper Motion

19.890 mas/yr

PM Right Ascension

14.97 mas/yr

PM Declination

-13.10 mas/yr

Galactic Cartesian (pc)

x = 0.189 · y = -0.696 · z = 0.693

Equatorial (J2000)

RA 285.18287° · Dec 43.83103°

Galactic ℓ, b

74.072° · 16.843°

Ecliptic λ, β

297.474° · 65.828°

HTM-20 index

170532617