Key parameters at a glance

A radius of 5.40 Earth radii
A mass of 19.00 Earth masses
Surface gravity around 0.65 g
An orbital period of 20.890 days
Semi-major axis 0.1540 AU
Equilibrium temperature 686 K (413 °C)
Distance from Earth 556.30 light-years
Earth Similarity Index 0.251
Travel time at Voyager 1 speed 9,810,318 years

1 sibling around K2-24

K2-24 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
K2-24 b this	Neptune-like	5.40	19.00	20.890	686	2016
K2-24 c	Neptune-like	7.50	15.40	42.339	542	2016

K2-24 b Planet Profile

Physical Specs

Radius

5.40 R⊕

Radius (Jupiter)

0.482 R♃

Mass

19.00 M⊕

Mass (Jupiter)

0.060 M♃

Density

0.64 g/cm³

Surface Gravity

0.65 g (Earth)

Classification

Planet Type

Neptune-like

ESI Score 0.251

HZ Position Inner

Controversial No

Discovery

Year 2016

Method Transit

Facility K2

Telescope 0.95 m Kepler Telescope

Size rank in cohort

Rank by radius

#327of 574

top 56.8%

This planet

5.40R⊕

Neptune-like median

6.39R⊕

Nearest-size peers

Kepler-328 c 5.40 R⊕ Kepler-1737 b 5.40 R⊕ HD 10180 e 5.39 R⊕

Metric	Earth	K2-24 b	Jupiter
Radius (R⊕)	1.00	5.40	11.21
Mass (M⊕)	1.00	19.00	317.83
Density (g/cm³)	5.51	0.64	1.33
Surface Gravity (g)	1.00	0.65	2.53
Insolation (S⊕)	1.00	52.00	0.037

Alternative Mass Estimates

Method	Value	Interpretation
Best measured mass	19.000 M⊕	Direct mass measurement (not derived).

Star Catalogue Identifiers

TIC

TIC 68048686

Gaia DR2

Gaia DR2 6049750234317822208

Gaia DR3

Gaia DR3 6049750234317822208

System

K2-24

Percentile among Neptune-like cohort

Radius 5.400 R⊕ · percentile 43 / cohort 574

Mass 19.000 M⊕ · percentile 25 / cohort 574

Orbital period 20.89 d · percentile 53 / cohort 524

Distance 170.56 pc · percentile 35 / cohort 572

ESI 0.251 · percentile 40 / cohort 574

Orbit & Habitability

Orbital Dynamics

Period

20.890 days

Semi-major axis

0.1540 AU

Eccentricity

0.060

Inclination

89.25 °

Year Length

A year here lasts approximately 20.89 Earth days (5.7% of a terrestrial year) on a nearly circular orbit at a mean orbital distance of 0.1540 AU.

Transit Fingerprint

Depth

0.221 %

Duration

5.498 h

Impact parameter b

0.470

Rp / R★

0.042640

Transit midpoint (BJD)

2,456,905.8855

Photometric dip

Transit produces a flux drop of 2,213 ppm lasting ≈ 5.50 h.

Extended Orbital Architecture

Planet / star radius ratio

0.042640

Semi-major axis / stellar radius

28.600

Impact parameter (b)

0.470

RV semi-amplitude (K)

4.250 m/s

Transit mid-time (BJD)

2,456,905.8855

Angular separation (arcsec)

0.90300

Eq. Temperature

686K

(413 °C)

Insolation (S⊕)

52.00

Earth = 1.00

Earth Similarity (ESI)

0.251

0 = alien, 1 = Earth-identical

Inside the inner HZ boundary (too hot for liquid water) — the surface is too hot to retain surface water.

Detection Signatures

Transit photometry

A transit dip has been observed from at least one telescope.

Radial velocity

Stellar wobble has been measured spectroscopically.

Transit timing variations

Gravitational interactions from neighbours have been detected.

Discovery Paper

Primary reference

Petigura et al. 2016

Instrument

Kepler CCD Array

Publication

2016-02

Observation locale

Space

Discovery cohort

Planets confirmed in 2016 at K2 (12 shown).

K2-72 d · Rocky Terrestrial K2-72 b · Rocky Terrestrial K2-91 b · Rocky Terrestrial K2-72 c · Rocky Terrestrial K2-102 b · Super-Earth K2-90 c · Super-Earth K2-72 e · Super-Earth K2-83 b · Rocky Terrestrial K2-88 b · Rocky Terrestrial K2-80 c · Super-Earth K2-83 c · Super-Earth K2-65 b · Super-Earth

Host System: K2-24

Spectral Class

G-type yellow (Sun-like)

Effective Temperature

5,625 K — cooler than the Sun (5,778 K)

Estimated Age

5.10 Gyr — older than the Sun (4.6 Gyr)

Stellar Radius

1.160 R☉

Stellar Mass

1.070 M☉

Metallicity [Fe/H]

0.34

Extended Stellar Properties

Surface gravity (log g)

4.290 dex

Stellar density

0.890 g/cm³

Systemic radial velocity

1.18 km/s

Rotational v·sin i

2.00 km/s

Activity index (log R'HK)

-5.244

Metallicity ratio

[Fe/H]

Distance

170.56 parsec

Light-years 556.30 ly

V-band magnitude

11.28 mag

Voyager-speed travel 9,810,318 yr

Multi-band Host Photometry — 15 bands

Astrometric Data

Parallax

5.835 mas

Total Proper Motion

83.958 mas/yr

PM Right Ascension

-59.92 mas/yr

PM Declination

-58.81 mas/yr

Galactic Cartesian (pc)

x = -0.417 · y = -0.805 · z = -0.422

Equatorial (J2000)

RA 242.57346° · Dec -24.99060°

Galactic ℓ, b

349.999° · 19.205°

Ecliptic λ, β

245.260° · -3.876°

HTM-20 index

229524126