Key parameters at a glance

A radius of 9.23 Earth radii
A mass of 62.50 Earth masses
Surface gravity around 0.73 g
An orbital period of 453.542 days
Semi-major axis 1.3292 AU
Equilibrium temperature 390 K (117 °C)
Distance from Earth 2,150.66 light-years
Earth Similarity Index 0.341
Travel time at Voyager 1 speed 37,926,823 years

Kepler-1981 b Planet Profile

Physical Specs

Radius

9.23 R⊕

Radius (Jupiter)

0.823 R♃

Mass

62.50 M⊕

Mass (Jupiter)

0.197 M♃

Density

0.44 g/cm³

Surface Gravity

0.73 g (Earth)

Classification

Planet Type

Neptune-like

ESI Score 0.341

HZ Position Inner

Controversial No

Discovery

Year 2023

Method Transit

Facility Kepler

Telescope 0.95 m Kepler Telescope

Size rank in cohort

Rank by radius

#66of 574

top 11.3%

This planet

9.23R⊕

Neptune-like median

6.39R⊕

Nearest-size peers

TOI-622 b 9.24 R⊕ HAT-P-38 b 9.25 R⊕ Kepler-695 b 9.21 R⊕

Metric	Earth	Kepler-1981 b	Jupiter
Radius (R⊕)	1.00	9.23	11.21
Mass (M⊕)	1.00	62.50	317.83
Density (g/cm³)	5.51	0.44	1.33
Surface Gravity (g)	1.00	0.73	2.53
Insolation (S⊕)	1.00	5.45	0.037

Star Catalogue Identifiers

TIC

TIC 121457557

Gaia DR2

Gaia DR2 2099583977992504576

Gaia DR3

Gaia DR3 2099583977992504576

System

Kepler-1981

Percentile among Neptune-like cohort

Radius 9.230 R⊕ · percentile 89 / cohort 574

Mass 62.500 M⊕ · percentile 80 / cohort 574

Orbital period 453.54 d · percentile 95 / cohort 524

Distance 659.40 pc · percentile 63 / cohort 572

ESI 0.341 · percentile 61 / cohort 574

Orbit & Habitability

Orbital Dynamics

Period

453.542 days

Semi-major axis

1.3292 AU

Eccentricity

0.000

Inclination

89.78 °

Year Length

A year here lasts about 1.24 Earth years on a nearly circular orbit at a mean orbital distance of 1.3292 AU.

Transit Fingerprint

Depth

0.086 %

Duration

17.026 h

Impact parameter b

0.633

Rp / R★

0.028130

Transit midpoint (BJD)

2,455,193.0617

Photometric dip

Transit produces a flux drop of 861 ppm lasting ≈ 17.03 h.

Extended Orbital Architecture

Planet / star radius ratio

0.028130

Semi-major axis / stellar radius

164.900

Impact parameter (b)

0.633

Transit mid-time (BJD)

2,455,193.0617

Angular separation (arcsec)

2.02000

Eq. Temperature

390K

(117 °C)

Insolation (S⊕)

5.45

Earth = 1.00

Earth Similarity (ESI)

0.341

0 = alien, 1 = Earth-identical

Inside the inner HZ boundary (too hot for liquid water) — the surface is too hot to retain surface water.

Discovery Paper

Primary reference

Valizadegan et al. 2023

Instrument

Kepler CCD Array

Publication

2023-05

Observation locale

Space

Discovery cohort

Planets confirmed in 2023 at Kepler (12 shown).

Kepler-1126 c · Super-Earth Kepler-2000 c · Super-Earth Kepler-1052 c · Sub-Neptune Kepler-311 d · Sub-Neptune Kepler-1996 c · Sub-Neptune Kepler-1162 c · Super-Earth Kepler-1996 b · Sub-Neptune Kepler-1610 c · Sub-Neptune Kepler-1801 c · Sub-Neptune Kepler-1995 b · Neptune-like Kepler-1992 b · Rocky Terrestrial Kepler-1986 b · Super-Earth

Host System: Kepler-1981

Spectral Class

G-type yellow (Sun-like)

Effective Temperature

5,874 K — hotter than the Sun (5,778 K)

Estimated Age

—

Stellar Radius

3.006 R☉

Stellar Mass

1.519 M☉

Metallicity [Fe/H]

0.12

Extended Stellar Properties

Surface gravity (log g)

3.664 dex

Stellar density

0.413 g/cm³

Metallicity ratio

[Fe/H]

Distance

659.40 parsec

Light-years 2,150.66 ly

V-band magnitude

13.56 mag

Voyager-speed travel 37,926,823 yr

Multi-band Host Photometry — 17 bands

Astrometric Data

Parallax

1.488 mas

Total Proper Motion

3.436 mas/yr

PM Right Ascension

1.83 mas/yr

PM Declination

2.91 mas/yr

Galactic Cartesian (pc)

x = 0.241 · y = -0.742 · z = 0.626

Equatorial (J2000)

RA 287.97547° · Dec 38.74030°

Galactic ℓ, b

70.084° · 12.912°

Ecliptic λ, β

299.136° · 60.374°

HTM-20 index

-227268191