Key parameters at a glance

A radius of 2.30 Earth radii
A mass of 444.96 Earth masses
Surface gravity around 84.11 g
An orbital period of 0.381 days
Semi-major axis 0.0090 AU
Equilibrium temperature 2,100 K (1827 °C)
Distance from Earth 795.29 light-years
Earth Similarity Index 0.040
Travel time at Voyager 1 speed 14,024,863 years
Almost certainly tidally locked to its host star given the close orbit

K2-22 b Planet Profile

Physical Specs

Radius

2.30 R⊕

Radius (Jupiter)

0.205 R♃

Mass

444.96 M⊕

Mass (Jupiter)

1.400 M♃

Density

— g/cm³

Surface Gravity

84.11 g (Earth)

Classification

Planet Type

Sub-Neptune

ESI Score 0.040

HZ Position Inner

Controversial No

Discovery

Year 2015

Method Transit

Facility K2

Telescope 0.95 m Kepler Telescope

Size rank in cohort

Rank by radius

#1499of 1978

top 75.7%

This planet

2.30R⊕

Sub-Neptune median

2.71R⊕

Nearest-size peers

Kepler-328 b 2.30 R⊕ Kepler-156 b 2.30 R⊕ GJ 536 c 2.30 R⊕

Metric	Earth	K2-22 b	Jupiter
Radius (R⊕)	1.00	2.30	11.21
Mass (M⊕)	1.00	444.96	317.83
Density (g/cm³)	5.51	—	1.33
Surface Gravity (g)	1.00	84.11	2.53
Insolation (S⊕)	1.00	114.00	0.037

Alternative Mass Estimates

Method	Value	Interpretation
Best measured mass	444.962 M⊕	Direct mass measurement (not derived).

Star Catalogue Identifiers

TIC

TIC 363445338

Gaia DR2

Gaia DR2 3811002791880297600

Gaia DR3

Gaia DR3 3811002791880297600

System

K2-22

Percentile among Sub-Neptune cohort

Radius 2.300 R⊕ · percentile 24 / cohort 1978

Mass 444.962 M⊕ · percentile 99 / cohort 1978

Orbital period 0.38 d · percentile 0 / cohort 1946

Distance 243.84 pc · percentile 31 / cohort 1975

ESI 0.040 · percentile 0 / cohort 1978

Orbit & Habitability

Orbital Dynamics

Period

0.381 days

Semi-major axis

0.0090 AU

Eccentricity

0.190

Inclination

90.60 °

Year Length

A year here lasts roughly 9.1 hours long on a mildly elliptical path at a mean orbital distance of 0.0090 AU.

Transit Fingerprint

Depth

0.624 %

Duration

0.586 h

Impact parameter b

0.650

Rp / R★

0.036600

Transit midpoint (BJD)

2,456,846.9432

Photometric dip

Transit produces a flux drop of 6,240 ppm lasting ≈ 0.59 h.

Extended Orbital Architecture

Planet / star radius ratio

0.036600

Semi-major axis / stellar radius

3.000

Impact parameter (b)

0.650

Transit mid-time (BJD)

2,456,846.9432

Long. of periastron (ω)

46.70°

Angular separation (arcsec)

0.03690

Eq. Temperature

2,100K

(1827 °C)

Insolation (S⊕)

114.00

Earth = 1.00

Earth Similarity (ESI)

0.040

0 = alien, 1 = Earth-identical

Inside the inner HZ boundary (too hot for liquid water) — the dayside is scorched. Close-orbiting tidally-locked around a cool host.

Discovery Paper

Primary reference

Sanchis Ojeda et al. 2015

Instrument

Kepler CCD Array

Publication

2015-10

Observation locale

Space

Discovery cohort

Planets confirmed in 2015 at K2 (12 shown).

K2-18 b · Sub-Neptune K2-9 b · Sub-Neptune K2-3 d · Super-Earth K2-3 c · Super-Earth K2-21 c · Sub-Neptune K2-5 c · Sub-Neptune K2-13 b · Super-Earth K2-3 b · Sub-Neptune K2-17 b · Sub-Neptune K2-21 b · Super-Earth K2-16 c · Sub-Neptune K2-5 b · Super-Earth

Host System: K2-22

Spectral Class

M-type red dwarf

Effective Temperature

3,879 K — cooler than the Sun (5,778 K)

Estimated Age

—

Stellar Radius

0.580 R☉

Stellar Mass

0.595 M☉

Metallicity [Fe/H]

0.03

Extended Stellar Properties

Surface gravity (log g)

4.700 dex

Stellar density

3.655 g/cm³

Metallicity ratio

[Fe/H]

Distance

243.84 parsec

Light-years 795.29 ly

V-band magnitude

15.57 mag

Voyager-speed travel 14,024,863 yr

Multi-band Host Photometry — 17 bands

Astrometric Data

Parallax

4.073 mas

Total Proper Motion

27.515 mas/yr

PM Right Ascension

-27.11 mas/yr

PM Declination

-4.71 mas/yr

Galactic Cartesian (pc)

x = -0.982 · y = 0.182 · z = 0.046

Equatorial (J2000)

RA 169.48270° · Dec 2.61904°

Galactic ℓ, b

256.532° · 56.816°

Ecliptic λ, β

169.302° · -1.754°

HTM-20 index

693867092