Key parameters at a glance

A radius of 2.21 Earth radii
A mass of 5.50 Earth masses
Surface gravity around 1.13 g
An orbital period of 40.031 days
Semi-major axis 0.2408 AU
Equilibrium temperature 617 K (344 °C)
Distance from Earth 2,707.05 light-years
Earth Similarity Index 0.429
Travel time at Voyager 1 speed 47,738,751 years

Kepler-1861 b Planet Profile

Physical Specs

Radius

2.21 R⊕

Radius (Jupiter)

0.197 R♃

Mass

5.50 M⊕

Mass (Jupiter)

0.017 M♃

Density

2.81 g/cm³

Surface Gravity

1.13 g (Earth)

Classification

Planet Type

Sub-Neptune

ESI Score 0.429

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

#1670of 1978

top 84.4%

This planet

2.21R⊕

Sub-Neptune median

2.71R⊕

Nearest-size peers

Kepler-23 d 2.21 R⊕ Kepler-19 b 2.21 R⊕ K2-335 b 2.21 R⊕

Metric	Earth	Kepler-1861 b	Jupiter
Radius (R⊕)	1.00	2.21	11.21
Mass (M⊕)	1.00	5.50	317.83
Density (g/cm³)	5.51	2.81	1.33
Surface Gravity (g)	1.00	1.13	2.53
Insolation (S⊕)	1.00	31.50	0.037

Star Catalogue Identifiers

TIC

TIC 27649489

Gaia DR2

Gaia DR2 2134956572729225728

Gaia DR3

Gaia DR3 2134956572729225728

System

Kepler-1861

Percentile among Sub-Neptune cohort

Radius 2.207 R⊕ · percentile 16 / cohort 1978

Mass 5.500 M⊕ · percentile 16 / cohort 1978

Orbital period 40.03 d · percentile 80 / cohort 1946

Distance 829.99 pc · percentile 67 / cohort 1975

ESI 0.429 · percentile 58 / cohort 1978

Orbit & Habitability

Orbital Dynamics

Period

40.031 days

Semi-major axis

0.2408 AU

Eccentricity

0.000

Inclination

89.70 °

Year Length

A year here lasts approximately 40.03 Earth days (11.0% of a terrestrial year) on a nearly circular orbit at a mean orbital distance of 0.2408 AU.

Transit Fingerprint

Depth

0.023 %

Duration

4.979 h

Impact parameter b

0.907

Rp / R★

0.013429

Transit midpoint (BJD)

2,454,981.8491

Photometric dip

Transit produces a flux drop of 229 ppm lasting ≈ 4.98 h.

Extended Orbital Architecture

Planet / star radius ratio

0.013429

Semi-major axis / stellar radius

28.000

Impact parameter (b)

0.907

Transit mid-time (BJD)

2,454,981.8491

Angular separation (arcsec)

0.29000

Eq. Temperature

617K

(344 °C)

Insolation (S⊕)

31.50

Earth = 1.00

Earth Similarity (ESI)

0.429

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. 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-1861

Spectral Class

G-type yellow (Sun-like)

Effective Temperature

5,855 K — hotter than the Sun (5,778 K)

Estimated Age

4.57 Gyr — younger than the Sun (4.6 Gyr)

Stellar Radius

1.373 R☉

Stellar Mass

1.161 M☉

Metallicity [Fe/H]

0.26

Extended Stellar Properties

Surface gravity (log g)

4.227 dex

Stellar density

2.684 g/cm³

Metallicity ratio

[Fe/H]

Distance

829.99 parsec

Light-years 2,707.05 ly

V-band magnitude

13.71 mag

Voyager-speed travel 47,738,751 yr

Multi-band Host Photometry — 16 bands

Astrometric Data

Parallax

1.176 mas

Total Proper Motion

3.445 mas/yr

PM Right Ascension

2.06 mas/yr

PM Declination

2.76 mas/yr

Galactic Cartesian (pc)

x = 0.281 · y = -0.579 · z = 0.765

Equatorial (J2000)

RA 295.84651° · Dec 49.93616°

Galactic ℓ, b

82.919° · 12.723°

Ecliptic λ, β

321.021° · 68.842°

HTM-20 index

-418792395