Key parameters at a glance

A radius of 1.10 Earth radii
A mass of 1.37 Earth masses
Surface gravity around 1.13 g
An orbital period of 0.813 days
Semi-major axis 0.0149 AU
Equilibrium temperature 1,347 K (1074 °C)
Distance from Earth 489.92 light-years
Earth Similarity Index 0.229
Travel time at Voyager 1 speed 8,639,720 years
Almost certainly tidally locked to its host star given the close orbit

K2-156 b Planet Profile

Physical Specs

Radius

1.10 R⊕

Radius (Jupiter)

0.098 R♃

Mass

1.37 M⊕

Mass (Jupiter)

0.004 M♃

Density

5.66 g/cm³

Surface Gravity

1.13 g (Earth)

Classification

Planet Type

Rocky Terrestrial

ESI Score 0.229

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

#224of 570

top 39.1%

This planet

1.10R⊕

Rocky Terrestrial median

1.01R⊕

Nearest-size peers

Kepler-392 c 1.10 R⊕ Kepler-59 b 1.10 R⊕ K2-239 d 1.10 R⊕

Metric	Earth	K2-156 b	Jupiter
Radius (R⊕)	1.00	1.10	11.21
Mass (M⊕)	1.00	1.37	317.83
Density (g/cm³)	5.51	5.66	1.33
Surface Gravity (g)	1.00	1.13	2.53
Insolation (S⊕)	1.00	—	0.037

Star Catalogue Identifiers

TIC

TIC 176868262

Gaia DR2

Gaia DR2 3596250888028092160

Gaia DR3

Gaia DR3 3596250888028092160

System

K2-156

Percentile among Rocky Terrestrial cohort

Radius 1.100 R⊕ · percentile 59 / cohort 570

Mass 1.370 M⊕ · percentile 54 / cohort 570

Orbital period 0.81 d · percentile 8 / cohort 567

Distance 150.21 pc · percentile 27 / cohort 566

ESI 0.229 · percentile 19 / cohort 570

Orbit & Habitability

Orbital Dynamics

Period

0.813 days

Semi-major axis

0.0149 AU

Eccentricity

—

Inclination

89.80 °

Year Length

A year here lasts roughly 19.5 hours long at a mean orbital distance of 0.0149 AU.

Transit Fingerprint

Depth

0.029 %

Duration

1.300 h

Impact parameter b

0.410

Rp / R★

0.016200

Transit midpoint (BJD)

2,457,641.6725

Photometric dip

Transit produces a flux drop of 290 ppm lasting ≈ 1.30 h.

Extended Orbital Architecture

Planet / star radius ratio

0.016200

Semi-major axis / stellar radius

4.400

Impact parameter (b)

0.410

Transit mid-time (BJD)

2,457,641.6725

Angular separation (arcsec)

0.09920

Eq. Temperature

1,347K

(1074 °C)

Insolation (S⊕)

—

Earth = 1.00

Earth Similarity (ESI)

0.229

0 = alien, 1 = Earth-identical

Insufficient insolation data — the dayside is scorched. Close-orbiting tidally-locked around a cool host.

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: K2-156

Spectral Class

K-type orange

Effective Temperature

4,460 K — cooler than the Sun (5,778 K)

Estimated Age

—

Stellar Radius

0.620 R☉

Stellar Mass

0.660 M☉

Metallicity [Fe/H]

-0.33

Extended Stellar Properties

Surface gravity (log g)

4.700 dex

Stellar density

2.685 g/cm³

Systemic radial velocity

-6.79 km/s

Rotational v·sin i

1.80 km/s

Metallicity ratio

[Fe/H]

Distance

150.21 parsec

Light-years 489.92 ly

V-band magnitude

13.40 mag

Voyager-speed travel 8,639,720 yr

Multi-band Host Photometry — 12 bands

Astrometric Data

Parallax

6.629 mas

Total Proper Motion

127.334 mas/yr

PM Right Ascension

-122.83 mas/yr

PM Declination

-33.59 mas/yr

Galactic Cartesian (pc)

x = -0.993 · y = -0.047 · z = -0.110

Equatorial (J2000)

RA 182.69967° · Dec -6.29436°

Galactic ℓ, b

285.059° · 55.161°

Ecliptic λ, β

184.979° · -4.702°

HTM-20 index

-1025597220