Key parameters at a glance

A radius of 2.90 Earth radii
A mass of 8.75 Earth masses
Surface gravity around 1.04 g
An orbital period of 6.414 days
Semi-major axis 0.0490 AU
Equilibrium temperature 442 K (169 °C)
Distance from Earth 457.87 light-years
Earth Similarity Index 0.521
Travel time at Voyager 1 speed 8,074,609 years
Almost certainly tidally locked to its host star given the close orbit

K2-124 b Planet Profile

Physical Specs

Radius

2.90 R⊕

Radius (Jupiter)

0.259 R♃

Mass

8.75 M⊕

Mass (Jupiter)

0.028 M♃

Density

1.97 g/cm³

Surface Gravity

1.04 g (Earth)

Classification

Planet Type

Sub-Neptune

ESI Score 0.521

HZ Position Inner

Controversial No

Discovery

Year 2017

Method Transit

Facility K2

Telescope 0.95 m Kepler Telescope

Size rank in cohort

Rank by radius

#621of 1978

top 31.3%

This planet

2.90R⊕

Sub-Neptune median

2.71R⊕

Nearest-size peers

Kepler-130 c 2.90 R⊕ Kepler-276 c 2.90 R⊕ Kepler-314 c 2.90 R⊕

Metric	Earth	K2-124 b	Jupiter
Radius (R⊕)	1.00	2.90	11.21
Mass (M⊕)	1.00	8.75	317.83
Density (g/cm³)	5.51	1.97	1.33
Surface Gravity (g)	1.00	1.04	2.53
Insolation (S⊕)	1.00	8.70	0.037

Star Catalogue Identifiers

TIC

TIC 197221381

Gaia DR2

Gaia DR2 686230534318440960

Gaia DR3

Gaia DR3 686230534318440960

System

K2-124

Percentile among Sub-Neptune cohort

Radius 2.900 R⊕ · percentile 68 / cohort 1978

Mass 8.750 M⊕ · percentile 62 / cohort 1978

Orbital period 6.41 d · percentile 19 / cohort 1946

Distance 140.39 pc · percentile 25 / cohort 1975

ESI 0.521 · percentile 73 / cohort 1978

Orbit & Habitability

Orbital Dynamics

Period

6.414 days

Semi-major axis

0.0490 AU

Eccentricity

0.080

Inclination

89.03 °

Year Length

A year here lasts approximately 6.41 Earth days (1.8% of a terrestrial year) on a nearly circular orbit at a mean orbital distance of 0.0490 AU.

Transit Fingerprint

Depth

0.553 %

Duration

1.680 h

Impact parameter b

0.470

Rp / R★

0.069000

Transit midpoint (BJD)

2,457,142.1811

Photometric dip

Transit produces a flux drop of 5,530 ppm lasting ≈ 1.68 h.

Extended Orbital Architecture

Planet / star radius ratio

0.069000

Semi-major axis / stellar radius

28.000

Impact parameter (b)

0.470

Transit mid-time (BJD)

2,457,142.1811

Long. of periastron (ω)

-26.80°

Angular separation (arcsec)

0.34900

Eq. Temperature

442K

(169 °C)

Insolation (S⊕)

8.70

Earth = 1.00

Earth Similarity (ESI)

0.521

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

Dressing et al. 2017

Instrument

Kepler CCD Array

Publication

2017-11

Observation locale

Space

Discovery cohort

Planets confirmed in 2017 at K2 (12 shown).

K2-129 b · Rocky Terrestrial K2-130 b · Super-Earth K2-133 b · Super-Earth K2-128 b · Super-Earth K2-133 c · Super-Earth K2-116 b · Rocky Terrestrial K2-125 b · Sub-Neptune K2-118 b · Sub-Neptune K2-136 d · Super-Earth K2-123 b · Sub-Neptune K2-136 c · Sub-Neptune K2-117 c · Sub-Neptune

Host System: K2-124

Spectral Class

M-type red dwarf

Effective Temperature

3,570 K — cooler than the Sun (5,778 K)

Estimated Age

—

Stellar Radius

0.388 R☉

Stellar Mass

0.390 M☉

Metallicity [Fe/H]

0.02

Extended Stellar Properties

Surface gravity (log g)

4.858 dex

Stellar density

9.580 g/cm³

Metallicity ratio

[Fe/H]

Distance

140.39 parsec

Light-years 457.87 ly

V-band magnitude

16.69 mag

Voyager-speed travel 8,074,609 yr

Multi-band Host Photometry — 17 bands

Astrometric Data

Parallax

7.095 mas

Total Proper Motion

32.727 mas/yr

PM Right Ascension

-30.27 mas/yr

PM Declination

12.43 mas/yr

Galactic Cartesian (pc)

x = -0.635 · y = 0.665 · z = 0.393

Equatorial (J2000)

RA 133.64105° · Dec 23.13295°

Galactic ℓ, b

203.231° · 36.726°

Ecliptic λ, β

129.607° · 5.493°

HTM-20 index

465142200