Key parameters at a glance

A radius of 2.33 Earth radii
A mass of 10.40 Earth masses
Surface gravity around 1.91 g
An orbital period of 16.141 days
Semi-major axis 0.1237 AU
Equilibrium temperature 804 K (531 °C)
Distance from Earth 397.82 light-years
Earth Similarity Index 0.343
Travel time at Voyager 1 speed 7,015,480 years

EPIC 229004835 b Planet Profile

Physical Specs

Radius

2.33 R⊕

Radius (Jupiter)

0.208 R♃

Mass

10.40 M⊕

Mass (Jupiter)

0.033 M♃

Density

4.49 g/cm³

Surface Gravity

1.91 g (Earth)

Classification

Planet Type

Sub-Neptune

ESI Score 0.343

HZ Position Inner

Controversial No

Discovery

Year 2023

Method Transit

Facility K2

Telescope 0.95 m Kepler Telescope

Size rank in cohort

Rank by radius

#1449of 1978

top 73.2%

This planet

2.33R⊕

Sub-Neptune median

2.71R⊕

Nearest-size peers

Kepler-783 c 2.33 R⊕ GJ 367 d 2.33 R⊕ Kepler-241 b 2.33 R⊕

Metric	Earth	EPIC 229004835 b	Jupiter
Radius (R⊕)	1.00	2.33	11.21
Mass (M⊕)	1.00	10.40	317.83
Density (g/cm³)	5.51	4.49	1.33
Surface Gravity (g)	1.00	1.91	2.53
Insolation (S⊕)	1.00	69.70	0.037

Alternative Mass Estimates

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

Star Catalogue Identifiers

TIC

TIC 94924543

Gaia DR2

Gaia DR2 3694798014985230336

Gaia DR3

Gaia DR3 3694798019281730944

System

EPIC 229004835

Percentile among Sub-Neptune cohort

Radius 2.332 R⊕ · percentile 27 / cohort 1978

Mass 10.400 M⊕ · percentile 76 / cohort 1978

Orbital period 16.14 d · percentile 54 / cohort 1946

Distance 121.97 pc · percentile 23 / cohort 1975

ESI 0.343 · percentile 39 / cohort 1978

Orbit & Habitability

Orbital Dynamics

Period

16.141 days

Semi-major axis

0.1237 AU

Eccentricity

0.230

Inclination

88.08 °

Year Length

A year here lasts approximately 16.14 Earth days (4.4% of a terrestrial year) on a mildly elliptical path at a mean orbital distance of 0.1237 AU.

Transit Fingerprint

Depth

0.036 %

Duration

2.100 h

Impact parameter b

0.380

Rp / R★

0.018400

Transit midpoint (BJD)

2,457,920.4458

Photometric dip

Transit produces a flux drop of 360 ppm lasting ≈ 2.10 h.

Extended Orbital Architecture

Planet / star radius ratio

0.018400

Semi-major axis / stellar radius

54.600

Impact parameter (b)

0.380

RV semi-amplitude (K)

2.760 m/s

Transit mid-time (BJD)

2,457,920.4458

Angular separation (arcsec)

1.01000

Eq. Temperature

804K

(531 °C)

Insolation (S⊕)

69.70

Earth = 1.00

Earth Similarity (ESI)

0.343

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.

Discovery Paper

Primary reference

Bonomo et al. 2023

Instrument

Kepler CCD Array

Publication

2023-04

Observation locale

Space

Discovery cohort

Planets confirmed in 2023 at K2 (4 shown).

K2-415 b · Rocky Terrestrial K2-2016-BLG-0005L b · Gas Giant K2-416 b · Sub-Neptune K2-417 b · Sub-Neptune

Host System: EPIC 229004835

Spectral Class

G-type yellow (Sun-like)

Effective Temperature

5,868 K — hotter than the Sun (5,778 K)

Estimated Age

4.90 Gyr — older than the Sun (4.6 Gyr)

Stellar Radius

0.999 R☉

Stellar Mass

0.970 M☉

Metallicity [Fe/H]

-0.12

Extended Stellar Properties

Surface gravity (log g)

4.470 dex

Stellar density

1.526 g/cm³

Rotational v·sin i

1.60 km/s

Activity index (log R'HK)

-4.984

Metallicity ratio

[Fe/H]

Distance

121.97 parsec

Light-years 397.82 ly

V-band magnitude

10.23 mag

Voyager-speed travel 7,015,480 yr

Multi-band Host Photometry — 12 bands

Astrometric Data

Parallax

8.170 mas

Total Proper Motion

133.543 mas/yr

PM Right Ascension

-129.13 mas/yr

PM Declination

-34.06 mas/yr

Galactic Cartesian (pc)

x = -0.993 · y = -0.113 · z = -0.025

Equatorial (J2000)

RA 186.48604° · Dec -1.40472°

Galactic ℓ, b

289.778° · 60.814°

Ecliptic λ, β

186.507° · 1.285°

HTM-20 index

1913839348