Key parameters at a glance

A radius of 2.33 Earth radii
A mass of 6.04 Earth masses
Surface gravity around 1.11 g
An orbital period of 8.583 days
Equilibrium temperature 932 K (659 °C)
Distance from Earth 845.42 light-years
Earth Similarity Index 0.277
Travel time at Voyager 1 speed 14,909,024 years

1 sibling around K2-389

K2-389 b shares its host star with 1 other confirmed planet. Side-by-side measurements below.

Planet	Type	Radius (R⊕)	Mass (M⊕)	Period (d)	Eq. T (K)	Year
K2-389 b this	Sub-Neptune	2.33	6.04	8.583	932	2022
K2-389 c	Sub-Neptune	2.04	4.82	20.851	—	2022

K2-389 b Planet Profile

Physical Specs

Radius

2.33 R⊕

Radius (Jupiter)

0.208 R♃

Mass

6.04 M⊕

Mass (Jupiter)

0.019 M♃

Density

2.62 g/cm³

Surface Gravity

1.11 g (Earth)

Classification

Planet Type

Sub-Neptune

ESI Score 0.277

HZ Position Inner

Controversial No

Discovery

Year 2022

Method Transit

Facility K2

Telescope 0.95 m Kepler Telescope

Size rank in cohort

Rank by radius

#1451of 1978

top 73.3%

This planet

2.33R⊕

Sub-Neptune median

2.71R⊕

Nearest-size peers

GJ 367 d 2.33 R⊕ Kepler-241 b 2.33 R⊕ Kepler-1983 b 2.33 R⊕

Metric	Earth	K2-389 b	Jupiter
Radius (R⊕)	1.00	2.33	11.21
Mass (M⊕)	1.00	6.04	317.83
Density (g/cm³)	5.51	2.62	1.33
Surface Gravity (g)	1.00	1.11	2.53
Insolation (S⊕)	1.00	179.00	0.037

Star Catalogue Identifiers

TIC

TIC 9030096

Gaia DR2

Gaia DR2 2435647095676990592

Gaia DR3

Gaia DR3 2435647095676990592

System

K2-389

Percentile among Sub-Neptune cohort

Radius 2.330 R⊕ · percentile 26 / cohort 1978

Mass 6.040 M⊕ · percentile 25 / cohort 1978

Orbital period 8.58 d · percentile 28 / cohort 1946

Distance 259.21 pc · percentile 32 / cohort 1975

ESI 0.277 · percentile 22 / cohort 1978

Orbit & Habitability

Orbital Dynamics

Period

8.583 days

Semi-major axis

— AU

Eccentricity

—

Inclination

— °

Year Length

A year here lasts approximately 8.58 Earth days (2.3% of a terrestrial year).

Transit Fingerprint

Duration

3.100 h

Impact parameter b

0.696

Rp / R★

0.018500

Transit midpoint (BJD)

2,457,742.7820

Extended Orbital Architecture

Planet / star radius ratio

0.018500

Semi-major axis / stellar radius

15.760

Impact parameter (b)

0.696

Transit mid-time (BJD)

2,457,742.7820

Eq. Temperature

932K

(659 °C)

Insolation (S⊕)

179.00

Earth = 1.00

Earth Similarity (ESI)

0.277

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

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 K2-381 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

Host System: K2-389

Spectral Class

G-type yellow (Sun-like)

Effective Temperature

5,773 K — cooler than the Sun (5,778 K)

Estimated Age

—

Stellar Radius

1.094 R☉

Stellar Mass

0.990 M☉

Metallicity [Fe/H]

0.04

Extended Stellar Properties

Surface gravity (log g)

4.310 dex

Stellar density

0.631 g/cm³

Rotational v·sin i

1.80 km/s

Activity index (log R'HK)

-5.119

Metallicity ratio

[Fe/H]

Distance

259.21 parsec

Light-years 845.42 ly

V-band magnitude

11.83 mag

Voyager-speed travel 14,909,024 yr

Multi-band Host Photometry — 17 bands

Astrometric Data

Parallax

3.830 mas

Total Proper Motion

76.091 mas/yr

PM Right Ascension

75.54 mas/yr

PM Declination

-9.13 mas/yr

Galactic Cartesian (pc)

x = 0.983 · y = -0.075 · z = -0.169

Equatorial (J2000)

RA 355.63042° · Dec -9.71358°

Galactic ℓ, b

76.645° · -66.177°

Ecliptic λ, β

352.117° · -7.177°

HTM-20 index

-999355743