Key parameters at a glance

A radius of 3.36 Earth radii
A mass of 11.20 Earth masses
Surface gravity around 0.99 g
An orbital period of 29.740 days
Equilibrium temperature 606 K (333 °C)
Distance from Earth 2,407.47 light-years
Earth Similarity Index 0.369
Travel time at Voyager 1 speed 42,455,817 years

K2-340 b Planet Profile

Physical Specs

Radius

3.36 R⊕

Radius (Jupiter)

0.300 R♃

Mass

11.20 M⊕

Mass (Jupiter)

0.035 M♃

Density

1.62 g/cm³

Surface Gravity

0.99 g (Earth)

Classification

Planet Type

Sub-Neptune

ESI Score 0.369

HZ Position Unknown

Controversial No

Discovery

Year 2021

Method Transit

Facility K2

Telescope 0.95 m Kepler Telescope

Size rank in cohort

Rank by radius

#242of 1978

top 12.2%

This planet

3.36R⊕

Sub-Neptune median

2.71R⊕

Nearest-size peers

Kepler-1057 b 3.36 R⊕ Kepler-1510 b 3.36 R⊕ Kepler-1083 b 3.36 R⊕

Metric	Earth	K2-340 b	Jupiter
Radius (R⊕)	1.00	3.36	11.21
Mass (M⊕)	1.00	11.20	317.83
Density (g/cm³)	5.51	1.62	1.33
Surface Gravity (g)	1.00	0.99	2.53
Insolation (S⊕)	1.00	—	0.037

Star Catalogue Identifiers

TIC

TIC 178246831

Gaia DR2

Gaia DR2 662705555330268928

Gaia DR3

Gaia DR3 662705555330268928

System

K2-340

Percentile among Sub-Neptune cohort

Radius 3.360 R⊕ · percentile 87 / cohort 1978

Mass 11.200 M⊕ · percentile 81 / cohort 1978

Orbital period 29.74 d · percentile 73 / cohort 1946

Distance 738.14 pc · percentile 61 / cohort 1975

ESI 0.369 · percentile 46 / cohort 1978

Orbit & Habitability

Orbital Dynamics

Period

29.740 days

Semi-major axis

— AU

Eccentricity

—

Inclination

— °

Year Length

A year here lasts approximately 29.74 Earth days (8.1% of a terrestrial year).

Transit Fingerprint

Depth

0.089 %

Duration

5.290 h

Impact parameter b

0.390

Rp / R★

0.026800

Transit midpoint (BJD)

2,457,143.8159

Photometric dip

Transit produces a flux drop of 888 ppm lasting ≈ 5.29 h.

Extended Orbital Architecture

Planet / star radius ratio

0.026800

Semi-major axis / stellar radius

40.800

Impact parameter (b)

0.390

Transit mid-time (BJD)

2,457,143.8159

Eq. Temperature

606K

(333 °C)

Insolation (S⊕)

—

Earth = 1.00

Earth Similarity (ESI)

0.369

0 = alien, 1 = Earth-identical

Insufficient insolation data — the surface is too hot to retain surface water.

Discovery Paper

Primary reference

De Leon et al. 2021

Instrument

Kepler CCD Array

Publication

2021-08

Observation locale

Space

Discovery cohort

Planets confirmed in 2021 at K2 (12 shown).

EPIC 220492298 b · Rocky Terrestrial EPIC 206042996 c · Rocky Terrestrial EPIC 212624936 b · Rocky Terrestrial EPIC 206024342 c · Super-Earth EPIC 201427007 b · Super-Earth K2-332 b · Sub-Neptune EPIC 212624936 c · Sub-Neptune EPIC 206024342 d · Sub-Neptune K2-345 b · Sub-Neptune K2-349 b · Super-Earth K2-343 c · Sub-Neptune K2-346 b · Sub-Neptune

Host System: K2-340

Spectral Class

G-type yellow (Sun-like)

Effective Temperature

5,532 K — cooler than the Sun (5,778 K)

Estimated Age

—

Stellar Radius

1.130 R☉

Stellar Mass

0.930 M☉

Metallicity [Fe/H]

0.08

Extended Stellar Properties

Surface gravity (log g)

4.300 dex

Stellar density

0.982 g/cm³

Metallicity ratio

[Fe/H]

Distance

738.14 parsec

Light-years 2,407.47 ly

V-band magnitude

14.43 mag

Voyager-speed travel 42,455,817 yr

Multi-band Host Photometry — 12 bands

Astrometric Data

Parallax

1.326 mas

Total Proper Motion

19.197 mas/yr

PM Right Ascension

-2.30 mas/yr

PM Declination

-19.06 mas/yr

Galactic Cartesian (pc)

x = -0.581 · y = 0.745 · z = 0.327

Equatorial (J2000)

RA 127.93734° · Dec 19.07459°

Galactic ℓ, b

205.729° · 30.366°

Ecliptic λ, β

125.520° · 0.191°

HTM-20 index

926987626