Key parameters at a glance

A radius of 2.29 Earth radii
A mass of 5.84 Earth masses
Surface gravity around 1.11 g
An orbital period of 9.899 days
Semi-major axis 0.0880 AU
Distance from Earth 227.01 light-years
Earth Similarity Index 0.735
Travel time at Voyager 1 speed 4,003,375 years

1 sibling around HD 35843

HD 35843 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
HD 35843 b this	Sub-Neptune	2.29	5.84	9.899	—	2025
HD 35843 c	Sub-Neptune	2.54	11.32	46.962	479	2025

HD 35843 b Planet Profile

Physical Specs

Radius

2.29 R⊕

Radius (Jupiter)

0.204 R♃

Mass

5.84 M⊕

Mass (Jupiter)

0.018 M♃

Density

2.67 g/cm³

Surface Gravity

1.11 g (Earth)

Classification

Planet Type

Sub-Neptune

ESI Score 0.735

HZ Position Unknown

Controversial No

Discovery

Year 2025

Method Radial Velocity

Facility Paranal Observatory

Telescope 8.2 m ESO VLT UT3 Melipal Telescope

Size rank in cohort

Rank by radius

#1519of 1978

top 76.7%

This planet

2.29R⊕

Sub-Neptune median

2.71R⊕

Nearest-size peers

Kepler-379 c 2.29 R⊕ Kepler-319 d 2.29 R⊕ Kepler-626 b 2.29 R⊕

Metric	Earth	HD 35843 b	Jupiter
Radius (R⊕)	1.00	2.29	11.21
Mass (M⊕)	1.00	5.84	317.83
Density (g/cm³)	5.51	2.67	1.33
Surface Gravity (g)	1.00	1.11	2.53
Insolation (S⊕)	1.00	—	0.037

Alternative Mass Estimates

Method	Value	Interpretation
Minimum mass (M sin i)	5.840 M⊕	Lower bound from radial-velocity fitting.

Star Catalogue Identifiers

HD 35843

HIP

HIP 25359

TIC

TIC 7422496

Gaia DR2

Gaia DR2 4799563663371481344

Gaia DR3

Gaia DR3 4799563663371481344

System

HD 35843

Percentile among Sub-Neptune cohort

Radius 2.290 R⊕ · percentile 23 / cohort 1978

Mass 5.840 M⊕ · percentile 22 / cohort 1978

Orbital period 9.90 d · percentile 33 / cohort 1946

Distance 69.60 pc · percentile 16 / cohort 1975

ESI 0.735 · percentile 96 / cohort 1978

Orbit & Habitability

Orbital Dynamics

Period

9.899 days

Semi-major axis

0.0880 AU

Eccentricity

0.000

Inclination

— °

Year Length

A year here lasts approximately 9.90 Earth days (2.7% of a terrestrial year) on a nearly circular orbit at a mean orbital distance of 0.0880 AU.

Eq. Temperature

—

Insolation (S⊕)

—

Earth = 1.00

Earth Similarity (ESI)

0.735

0 = alien, 1 = Earth-identical

Discovery Paper

Primary reference

Hesse et al. 2025

Instrument

ESPRESSO

Publication

2025-05

Observation locale

Ground

Discovery cohort

Planets confirmed in 2025 at Paranal Observatory (8 shown).

TOI-771 c · Super-Earth WISPIT 1 c · Gas Giant K2-157 d · Neptune-like WISPIT 1 b · Gas Giant WISPIT 2 b · Gas Giant K2-157 c · Neptune-like HD 143811 AB b · Gas Giant HD 135344 A b · Gas Giant

Host System: HD 35843

Spectral Class

G-type yellow (Sun-like)

Effective Temperature

5,666 K — cooler than the Sun (5,778 K)

Estimated Age

2.50 Gyr — younger than the Sun (4.6 Gyr)

Stellar Radius

0.897 R☉

Stellar Mass

0.940 M☉

Metallicity [Fe/H]

-0.27

Extended Stellar Properties

Surface gravity (log g)

4.470 dex

Stellar density

1.840 g/cm³

Systemic radial velocity

13.77 km/s

Rotational v·sin i

2.09 km/s

Rotation period

25.49 days

Activity index (log R'HK)

-5.010

Metallicity ratio

[Fe/H]

Distance

69.60 parsec

Light-years 227.01 ly

V-band magnitude

9.36 mag

Voyager-speed travel 4,003,375 yr

Multi-band Host Photometry — 11 bands

Astrometric Data

Parallax

14.338 mas

Total Proper Motion

118.815 mas/yr

PM Right Ascension

-44.10 mas/yr

PM Declination

-110.33 mas/yr

Galactic Cartesian (pc)

x = 0.107 · y = 0.706 · z = -0.700

Equatorial (J2000)

RA 81.34889° · Dec -44.43128°

Galactic ℓ, b

250.098° · -33.521°

Ecliptic λ, β

73.777° · -67.384°

HTM-20 index

-1609434883