Key parameters at a glance

A radius of 2.00 Earth radii
A mass of 4.66 Earth masses
Surface gravity around 1.17 g
An orbital period of 7.516 days
Semi-major axis 0.0614 AU
Equilibrium temperature 497 K (224 °C)
Distance from Earth 466.81 light-years
Earth Similarity Index 0.542
Travel time at Voyager 1 speed 8,232,208 years
Almost certainly tidally locked to its host star given the close orbit

K2-153 b Planet Profile

Physical Specs

Radius

2.00 R⊕

Radius (Jupiter)

0.178 R♃

Mass

4.66 M⊕

Mass (Jupiter)

0.015 M♃

Density

3.20 g/cm³

Surface Gravity

1.17 g (Earth)

Classification

Planet Type

Sub-Neptune

ESI Score 0.542

HZ Position Inner

Controversial No

Discovery

Year 2018

Method Transit

Facility K2

Telescope 0.95 m Kepler Telescope

Size rank in cohort

Rank by radius

#1955of 1978

top 98.8%

This planet

2.00R⊕

Sub-Neptune median

2.71R⊕

Nearest-size peers

Kepler-32 c 2.00 R⊕ Kepler-238 f 2.00 R⊕ Kepler-242 c 2.00 R⊕

Metric	Earth	K2-153 b	Jupiter
Radius (R⊕)	1.00	2.00	11.21
Mass (M⊕)	1.00	4.66	317.83
Density (g/cm³)	5.51	3.20	1.33
Surface Gravity (g)	1.00	1.17	2.53
Insolation (S⊕)	1.00	11.80	0.037

Star Catalogue Identifiers

TIC

TIC 397056271

Gaia DR2

Gaia DR2 3700937760929835648

Gaia DR3

Gaia DR3 3700937760929835648

System

K2-153

Percentile among Sub-Neptune cohort

Radius 2.000 R⊕ · percentile 0 / cohort 1978

Mass 4.660 M⊕ · percentile 2 / cohort 1978

Orbital period 7.52 d · percentile 24 / cohort 1946

Distance 143.13 pc · percentile 25 / cohort 1975

ESI 0.542 · percentile 76 / cohort 1978

Orbit & Habitability

Orbital Dynamics

Period

7.516 days

Semi-major axis

0.0614 AU

Eccentricity

—

Inclination

— °

Year Length

A year here lasts approximately 7.52 Earth days (2.1% of a terrestrial year) at a mean orbital distance of 0.0614 AU.

Transit Fingerprint

Depth

0.129 %

Duration

2.300 h

Impact parameter b

0.420

Rp / R★

0.034800

Transit midpoint (BJD)

2,457,588.4270

Photometric dip

Transit produces a flux drop of 1,290 ppm lasting ≈ 2.30 h.

Extended Orbital Architecture

Planet / star radius ratio

0.034800

Semi-major axis / stellar radius

23.600

Impact parameter (b)

0.420

Transit mid-time (BJD)

2,457,588.4270

Angular separation (arcsec)

0.42900

Eq. Temperature

497K

(224 °C)

Insolation (S⊕)

11.80

Earth = 1.00

Earth Similarity (ESI)

0.542

0 = alien, 1 = Earth-identical

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

Discovery Paper

Primary reference

Hirano 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: K2-153

Spectral Class

M-type red dwarf

Effective Temperature

3,845 K — cooler than the Sun (5,778 K)

Estimated Age

—

Stellar Radius

0.530 R☉

Stellar Mass

0.550 M☉

Metallicity [Fe/H]

-0.09

Extended Stellar Properties

Surface gravity (log g)

4.730 dex

Stellar density

4.880 g/cm³

Metallicity ratio

[Fe/H]

Distance

143.13 parsec

Light-years 466.81 ly

V-band magnitude

14.96 mag

Voyager-speed travel 8,232,208 yr

Multi-band Host Photometry — 17 bands

Astrometric Data

Parallax

6.958 mas

Total Proper Motion

76.962 mas/yr

PM Right Ascension

-75.26 mas/yr

PM Declination

-16.10 mas/yr

Galactic Cartesian (pc)

x = -0.997 · y = -0.066 · z = 0.035

Equatorial (J2000)

RA 183.80887° · Dec 2.02088°

Galactic ℓ, b

282.350° · 63.437°

Ecliptic λ, β

182.688° · 3.369°

HTM-20 index

-1498724510