Key parameters at a glance

A radius of 2.08 Earth radii
A mass of 4.99 Earth masses
Surface gravity around 1.15 g
An orbital period of 11.660 days
Semi-major axis 0.1016 AU
Equilibrium temperature 834 K (561 °C)
Distance from Earth 3,185.69 light-years
Earth Similarity Index 0.325
Travel time at Voyager 1 speed 56,179,575 years

Kepler-1866 b Planet Profile

Physical Specs

Radius

2.08 R⊕

Radius (Jupiter)

0.186 R♃

Mass

4.99 M⊕

Mass (Jupiter)

0.016 M♃

Density

3.04 g/cm³

Surface Gravity

1.15 g (Earth)

Classification

Planet Type

Sub-Neptune

ESI Score 0.325

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

#1845of 1978

top 93.2%

This planet

2.08R⊕

Sub-Neptune median

2.71R⊕

Nearest-size peers

Kepler-1195 b 2.08 R⊕ Kepler-405 b 2.08 R⊕ Kepler-237 c 2.08 R⊕

Metric	Earth	Kepler-1866 b	Jupiter
Radius (R⊕)	1.00	2.08	11.21
Mass (M⊕)	1.00	4.99	317.83
Density (g/cm³)	5.51	3.04	1.33
Surface Gravity (g)	1.00	1.15	2.53
Insolation (S⊕)	1.00	114.36	0.037

Star Catalogue Identifiers

TIC

TIC 158213683

Gaia DR2

Gaia DR2 2106290208647252608

Gaia DR3

Gaia DR3 2106290208647252608

System

Kepler-1866

Percentile among Sub-Neptune cohort

Radius 2.082 R⊕ · percentile 7 / cohort 1978

Mass 4.990 M⊕ · percentile 8 / cohort 1978

Orbital period 11.66 d · percentile 40 / cohort 1946

Distance 976.74 pc · percentile 77 / cohort 1975

ESI 0.325 · percentile 34 / cohort 1978

Orbit & Habitability

Orbital Dynamics

Period

11.660 days

Semi-major axis

0.1016 AU

Eccentricity

0.000

Inclination

76.07 °

Year Length

A year here lasts approximately 11.66 Earth days (3.2% of a terrestrial year) on a nearly circular orbit at a mean orbital distance of 0.1016 AU.

Transit Fingerprint

Depth

0.018 %

Duration

4.921 h

Impact parameter b

0.954

Rp / R★

0.011100

Transit midpoint (BJD)

2,454,973.6252

Photometric dip

Transit produces a flux drop of 181 ppm lasting ≈ 4.92 h.

Extended Orbital Architecture

Planet / star radius ratio

0.011100

Semi-major axis / stellar radius

4.090

Impact parameter (b)

0.954

Transit mid-time (BJD)

2,454,973.6252

Angular separation (arcsec)

0.10400

Eq. Temperature

834K

(561 °C)

Insolation (S⊕)

114.36

Earth = 1.00

Earth Similarity (ESI)

0.325

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-1866

Spectral Class

G-type yellow (Sun-like)

Effective Temperature

5,791 K — hotter than the Sun (5,778 K)

Estimated Age

0.30 Gyr — younger than the Sun (4.6 Gyr)

Stellar Radius

1.083 R☉

Stellar Mass

1.030 M☉

Metallicity [Fe/H]

0.16

Extended Stellar Properties

Surface gravity (log g)

4.381 dex

Stellar density

0.009 g/cm³

Metallicity ratio

[Fe/H]

Distance

976.74 parsec

Light-years 3,185.69 ly

V-band magnitude

14.42 mag

Voyager-speed travel 56,179,575 yr

Multi-band Host Photometry — 16 bands

Astrometric Data

Parallax

0.995 mas

Total Proper Motion

4.015 mas/yr

PM Right Ascension

1.63 mas/yr

PM Declination

3.67 mas/yr

Galactic Cartesian (pc)

x = 0.199 · y = -0.683 · z = 0.703

Equatorial (J2000)

RA 286.22465° · Dec 44.65449°

Galactic ℓ, b

75.160° · 16.458°

Ecliptic λ, β

299.793° · 66.423°

HTM-20 index

-1980678251