Key parameters at a glance

A radius of 1.38 Earth radii
A mass of 3.28 Earth masses
Surface gravity around 1.72 g
An orbital period of 2.156 days
Semi-major axis 0.0266 AU
Equilibrium temperature 796 K (523 °C)
Distance from Earth 116.41 light-years
Earth Similarity Index 0.376
Travel time at Voyager 1 speed 2,052,901 years
Almost certainly tidally locked to its host star given the close orbit

3 siblings around LHS 1903

LHS 1903 b shares its host star with 3 other confirmed planets. Side-by-side measurements below.

Planet	Type	Radius (R⊕)	Mass (M⊕)	Period (d)	Eq. T (K)	Year
LHS 1903 b this	Super-Earth	1.38	3.28	2.156	796	2026
LHS 1903 c	Sub-Neptune	2.05	4.55	6.226	559	2026
LHS 1903 d	Sub-Neptune	2.50	5.96	12.566	442	2026
LHS 1903 e	Super-Earth	1.73	5.79	29.318	333	2026

LHS 1903 b Planet Profile

Physical Specs

Radius

1.38 R⊕

Radius (Jupiter)

0.123 R♃

Mass

3.28 M⊕

Mass (Jupiter)

0.010 M♃

Density

6.82 g/cm³

Surface Gravity

1.72 g (Earth)

Classification

Planet Type

Super-Earth

ESI Score 0.376

HZ Position Inner

Controversial No

Discovery

Year 2026

Method Transit

Facility Transiting Exoplanet Survey Satellite (TESS)

Telescope 0.1 m TESS Telescope

Size rank in cohort

Rank by radius

#951of 1176

top 80.8%

This planet

1.38R⊕

Super-Earth median

1.60R⊕

Nearest-size peers

Kepler-323 b 1.38 R⊕ Kepler-84 d 1.38 R⊕ Kepler-353 c 1.38 R⊕

Metric	Earth	LHS 1903 b	Jupiter
Radius (R⊕)	1.00	1.38	11.21
Mass (M⊕)	1.00	3.28	317.83
Density (g/cm³)	5.51	6.82	1.33
Surface Gravity (g)	1.00	1.72	2.53
Insolation (S⊕)	1.00	66.66	0.037

Alternative Mass Estimates

Method	Value	Interpretation
Best measured mass	3.280 M⊕	Direct mass measurement (not derived).

Star Catalogue Identifiers

HIP

HIP 34730

TIC

TIC 318022259

Gaia DR2

Gaia DR2 978086481343568128

Gaia DR3

Gaia DR3 978086481343568128

System

LHS 1903

Percentile among Super-Earth cohort

Radius 1.382 R⊕ · percentile 19 / cohort 1176

Mass 3.280 M⊕ · percentile 50 / cohort 1176

Orbital period 2.16 d · percentile 13 / cohort 1164

Distance 35.69 pc · percentile 8 / cohort 1171

ESI 0.376 · percentile 56 / cohort 1176

Orbit & Habitability

Orbital Dynamics

Period

2.156 days

Semi-major axis

0.0266 AU

Eccentricity

0.015

Inclination

— °

Year Length

A year here lasts approximately 2.16 Earth days (0.6% of a terrestrial year) on a nearly circular orbit at a mean orbital distance of 0.0266 AU.

Transit Fingerprint

Depth

0.055 %

Duration

1.562 h

Impact parameter b

0.174

Rp / R★

0.023510

Transit midpoint (BJD)

2,458,844.5771

Photometric dip

Transit produces a flux drop of 553 ppm lasting ≈ 1.56 h.

Extended Orbital Architecture

Planet / star radius ratio

0.023510

Semi-major axis / stellar radius

10.590

Impact parameter (b)

0.174

RV semi-amplitude (K)

2.460 m/s

Transit mid-time (BJD)

2,458,844.5771

Long. of periastron (ω)

216.00°

Angular separation (arcsec)

0.74400

Eq. Temperature

796K

(523 °C)

Insolation (S⊕)

66.66

Earth = 1.00

Earth Similarity (ESI)

0.376

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.

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

Wilson et al. 2026

Instrument

TESS CCD Array

Publication

2026-02

Observation locale

Space

Discovery cohort

Planets confirmed in 2026 at Transiting Exoplanet Survey Satellite (TESS) (12 shown).

TOI-2094 b · Super-Earth TOI-6716 b · Rocky Terrestrial TOI-1080 b · Rocky Terrestrial TOI-1243 b · Sub-Neptune TOI-4529 b · Super-Earth TOI-7384 b · Sub-Neptune LHS 1903 d · Sub-Neptune LHS 1903 c · Sub-Neptune TOI-5734 b · Sub-Neptune TOI-5788 c · Sub-Neptune TOI-5788 b · Super-Earth TOI-1232 c · Neptune-like

Host System: LHS 1903

Spectral Class

M-type red dwarf

Effective Temperature

3,664 K — cooler than the Sun (5,778 K)

Estimated Age

7.08 Gyr — older than the Sun (4.6 Gyr)

Stellar Radius

0.539 R☉

Stellar Mass

0.538 M☉

Metallicity [Fe/H]

-0.11

Extended Stellar Properties

Surface gravity (log g)

4.750 dex

Stellar density

5.343 g/cm³

Rotation period

40.80 days

Metallicity ratio

[Fe/H]

Distance

35.69 parsec

Light-years 116.41 ly

V-band magnitude

12.23 mag

Voyager-speed travel 2,052,901 yr

Multi-band Host Photometry — 7 bands

Astrometric Data

Parallax

27.989 mas

Total Proper Motion

578.094 mas/yr

PM Right Ascension

-93.08 mas/yr

PM Declination

-570.55 mas/yr

Galactic Cartesian (pc)

x = -0.204 · y = 0.633 · z = 0.747

Equatorial (J2000)

RA 107.86583° · Dec 48.32793°

Galactic ℓ, b

168.989° · 23.094°

Ecliptic λ, β

103.079° · 25.697°

HTM-20 index

-778388913