Key parameters at a glance

A radius of 2.64 Earth radii
A mass of 7.46 Earth masses
Surface gravity around 1.07 g
An orbital period of 10.060 days
Semi-major axis 0.0887 AU
Equilibrium temperature 794 K (521 °C)
Distance from Earth 643.50 light-years
Earth Similarity Index 0.312
Travel time at Voyager 1 speed 11,348,166 years

1 sibling around K2-158

K2-158 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
K2-158 c	Super-Earth	1.28	2.18	5.903	948	2018
K2-158 b this	Sub-Neptune	2.64	7.46	10.060	794	2018

K2-158 b Planet Profile

Physical Specs

Radius

2.64 R⊕

Radius (Jupiter)

0.236 R♃

Mass

7.46 M⊕

Mass (Jupiter)

0.024 M♃

Density

2.23 g/cm³

Surface Gravity

1.07 g (Earth)

Classification

Planet Type

Sub-Neptune

ESI Score 0.312

HZ Position Unknown

Controversial No

Discovery

Year 2018

Method Transit

Facility K2

Telescope 0.95 m Kepler Telescope

Size rank in cohort

Rank by radius

#958of 1978

top 48.4%

This planet

2.64R⊕

Sub-Neptune median

2.71R⊕

Nearest-size peers

TOI-421 b 2.64 R⊕ Kepler-635 b 2.64 R⊕ Kepler-571 b 2.64 R⊕

Metric	Earth	K2-158 b	Jupiter
Radius (R⊕)	1.00	2.64	11.21
Mass (M⊕)	1.00	7.46	317.83
Density (g/cm³)	5.51	2.23	1.33
Surface Gravity (g)	1.00	1.07	2.53
Insolation (S⊕)	1.00	—	0.037

Star Catalogue Identifiers

TIC

TIC 35021200

Gaia DR2

Gaia DR2 3596003497911958528

Gaia DR3

Gaia DR3 3596003497911958528

System

K2-158

Percentile among Sub-Neptune cohort

Radius 2.640 R⊕ · percentile 51 / cohort 1978

Mass 7.460 M⊕ · percentile 47 / cohort 1978

Orbital period 10.06 d · percentile 34 / cohort 1946

Distance 197.30 pc · percentile 29 / cohort 1975

ESI 0.312 · percentile 31 / cohort 1978

Orbit & Habitability

Orbital Dynamics

Period

10.060 days

Semi-major axis

0.0887 AU

Eccentricity

—

Inclination

88.40 °

Year Length

A year here lasts approximately 10.06 Earth days (2.8% of a terrestrial year) at a mean orbital distance of 0.0887 AU.

Transit Fingerprint

Depth

0.070 %

Duration

3.800 h

Impact parameter b

0.380

Rp / R★

0.025500

Transit midpoint (BJD)

2,457,590.4834

Photometric dip

Transit produces a flux drop of 700 ppm lasting ≈ 3.80 h.

Extended Orbital Architecture

Planet / star radius ratio

0.025500

Semi-major axis / stellar radius

19.100

Impact parameter (b)

0.380

Transit mid-time (BJD)

2,457,590.4834

Angular separation (arcsec)

0.45000

Eq. Temperature

794K

(521 °C)

Insolation (S⊕)

—

Earth = 1.00

Earth Similarity (ESI)

0.312

0 = alien, 1 = Earth-identical

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

Discovery Paper

Primary reference

Mayo et al. 2018

Instrument

Kepler CCD Array

Publication

2018-03

Observation locale

Space

Discovery cohort

Planets confirmed in 2018 at K2 (12 shown).

K2-190 c · Rocky Terrestrial K2-183 b · Rocky Terrestrial K2-209 b · Rocky Terrestrial K2-210 b · Rocky Terrestrial K2-165 b · Super-Earth K2-169 b · Super-Earth K2-148 b · Super-Earth K2-219 b · Super-Earth K2-190 b · Super-Earth K2-200 b · Super-Earth K2-201 b · Super-Earth K2-170 b · Super-Earth

Host System: K2-158

Spectral Class

G-type yellow (Sun-like)

Effective Temperature

5,503 K — cooler than the Sun (5,778 K)

Estimated Age

—

Stellar Radius

0.950 R☉

Stellar Mass

0.920 M☉

Metallicity [Fe/H]

0.07

Extended Stellar Properties

Surface gravity (log g)

4.450 dex

Stellar density

1.575 g/cm³

Systemic radial velocity

-36.00 km/s

Metallicity ratio

[Fe/H]

Distance

197.30 parsec

Light-years 643.50 ly

V-band magnitude

11.77 mag

Voyager-speed travel 11,348,166 yr

Multi-band Host Photometry — 12 bands

Astrometric Data

Parallax

5.040 mas

Total Proper Motion

62.859 mas/yr

PM Right Ascension

-62.52 mas/yr

PM Declination

6.56 mas/yr

Galactic Cartesian (pc)

x = -0.995 · y = 0.001 · z = -0.100

Equatorial (J2000)

RA 179.93971° · Dec -5.72169°

Galactic ℓ, b

280.198° · 54.853°

Ecliptic λ, β

182.223° · -5.272°

HTM-20 index

1076585824