Key parameters at a glance

A radius of 2.42 Earth radii
A mass of 10.40 Earth masses
Surface gravity around 1.78 g
An orbital period of 36.577 days
Semi-major axis 0.2170 AU
Equilibrium temperature 641 K (368 °C)
Distance from Earth 344.03 light-years
Earth Similarity Index 0.421
Travel time at Voyager 1 speed 6,066,957 years

2 siblings around HD 224018

HD 224018 c shares its host star with 2 other confirmed planets. Side-by-side measurements below.

Planet	Type	Radius (R⊕)	Mass (M⊕)	Period (d)	Eq. T (K)	Year
HD 224018 b	Rocky Terrestrial	0.91	4.10	10.641	968	2025
HD 224018 c this	Sub-Neptune	2.42	10.40	36.577	641	2025
HD 224018 d	Sub-Neptune	2.40	4.20	138.073	411	2025

HD 224018 c Planet Profile

Physical Specs

Radius

2.42 R⊕

Radius (Jupiter)

0.216 R♃

Mass

10.40 M⊕

Mass (Jupiter)

0.033 M♃

Density

4.00 g/cm³

Surface Gravity

1.78 g (Earth)

Classification

Planet Type

Sub-Neptune

ESI Score 0.421

HZ Position Unknown

Controversial No

Discovery

Year 2025

Method Transit

Facility K2

Telescope 0.95 m Kepler Telescope

Size rank in cohort

Rank by radius

#1299of 1978

top 65.6%

This planet

2.42R⊕

Sub-Neptune median

2.71R⊕

Nearest-size peers

HD 1461 b 2.42 R⊕ Kepler-717 b 2.42 R⊕ K2-43 c 2.42 R⊕

Metric	Earth	HD 224018 c	Jupiter
Radius (R⊕)	1.00	2.42	11.21
Mass (M⊕)	1.00	10.40	317.83
Density (g/cm³)	5.51	4.00	1.33
Surface Gravity (g)	1.00	1.78	2.53
Insolation (S⊕)	1.00	—	0.037

Alternative Mass Estimates

Method	Value	Interpretation
Best measured mass	10.400 M⊕	Direct mass measurement (not derived).

Star Catalogue Identifiers

HD 224018

TIC

TIC 248608315

Gaia DR2

Gaia DR2 2446440348493043968

Gaia DR3

Gaia DR3 2446440348493043968

System

HD 224018

Percentile among Sub-Neptune cohort

Radius 2.420 R⊕ · percentile 34 / cohort 1978

Mass 10.400 M⊕ · percentile 76 / cohort 1978

Orbital period 36.58 d · percentile 78 / cohort 1946

Distance 105.48 pc · percentile 20 / cohort 1975

ESI 0.421 · percentile 57 / cohort 1978

Orbit & Habitability

Orbital Dynamics

Period

36.577 days

Semi-major axis

0.2170 AU

Eccentricity

0.020

Inclination

89.80 °

Year Length

A year here lasts approximately 36.58 Earth days (10.0% of a terrestrial year) on a nearly circular orbit at a mean orbital distance of 0.2170 AU.

Transit Fingerprint

Rp / R★

0.019350

Transit midpoint (BJD)

2,457,778.1544

Extended Orbital Architecture

Planet / star radius ratio

0.019350

RV semi-amplitude (K)

1.990 m/s

Transit mid-time (BJD)

2,457,778.1544

Long. of periastron (ω)

230.00°

Angular separation (arcsec)

2.06000

Eq. Temperature

641K

(368 °C)

Insolation (S⊕)

—

Earth = 1.00

Earth Similarity (ESI)

0.421

0 = alien, 1 = Earth-identical

Insufficient insolation data — 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.

Discovery Paper

Primary reference

Damasso et al. 2025

Instrument

Kepler CCD Array

Publication

2025-08

Observation locale

Space

Host System: HD 224018

Spectral Class

G-type yellow (Sun-like)

Effective Temperature

5,784 K — hotter than the Sun (5,778 K)

Estimated Age

7.00 Gyr — older than the Sun (4.6 Gyr)

Stellar Radius

1.147 R☉

Stellar Mass

1.013 M☉

Metallicity [Fe/H]

0.05

Extended Stellar Properties

Surface gravity (log g)

4.320 dex

Stellar density

0.902 g/cm³

Systemic radial velocity

-62.77 km/s

Rotational v·sin i

2.10 km/s

Metallicity ratio

[Fe/H]

Distance

105.48 parsec

Light-years 344.03 ly

V-band magnitude

9.72 mag

Voyager-speed travel 6,066,957 yr

Multi-band Host Photometry — 12 bands

Astrometric Data

Parallax

9.452 mas

Total Proper Motion

112.877 mas/yr

PM Right Ascension

-112.58 mas/yr

PM Declination

-8.19 mas/yr

Galactic Cartesian (pc)

x = 0.996 · y = -0.024 · z = -0.082

Equatorial (J2000)

RA 358.63901° · Dec -4.72334°

Galactic ℓ, b

89.242° · -63.810°

Ecliptic λ, β

356.867° · -3.792°

HTM-20 index

1167457204