Key parameters at a glance

A radius of 1.73 Earth radii
A mass of 5.79 Earth masses
Surface gravity around 1.93 g
An orbital period of 29.318 days
Semi-major axis 0.1514 AU
Equilibrium temperature 333 K (60 °C)
Distance from Earth 116.41 light-years
Earth Similarity Index 0.799
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 e 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	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 this	Super-Earth	1.73	5.79	29.318	333	2026

LHS 1903 e Planet Profile

Physical Specs

Radius

1.73 R⊕

Radius (Jupiter)

0.155 R♃

Mass

5.79 M⊕

Mass (Jupiter)

0.018 M♃

Density

6.10 g/cm³

Surface Gravity

1.93 g (Earth)

Classification

Planet Type

Super-Earth

ESI Score 0.799

HZ Position Inner

Controversial No

Discovery

Year 2026

Method Transit

Facility CHaracterising ExOPlanets Satellite (CHEOPS)

Telescope 0.3 m Ritchey-Chretien Telescope

Size rank in cohort

Rank by radius

#355of 1176

top 30.1%

This planet

1.73R⊕

Super-Earth median

1.60R⊕

Nearest-size peers

TOI-5799 b 1.73 R⊕ Kepler-327 d 1.73 R⊕ Kepler-1608 b 1.73 R⊕

Metric	Earth	LHS 1903 e	Jupiter
Radius (R⊕)	1.00	1.73	11.21
Mass (M⊕)	1.00	5.79	317.83
Density (g/cm³)	5.51	6.10	1.33
Surface Gravity (g)	1.00	1.93	2.53
Insolation (S⊕)	1.00	2.05	0.037

Alternative Mass Estimates

Method	Value	Interpretation
Best measured mass	5.790 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 1.732 R⊕ · percentile 70 / cohort 1176

Mass 5.790 M⊕ · percentile 93 / cohort 1176

Orbital period 29.32 d · percentile 91 / cohort 1164

Distance 35.69 pc · percentile 8 / cohort 1171

ESI 0.799 · percentile 89 / cohort 1176

Orbit & Habitability

Orbital Dynamics

Period

29.318 days

Semi-major axis

0.1514 AU

Eccentricity

0.014

Inclination

— °

Year Length

A year here lasts approximately 29.32 Earth days (8.0% of a terrestrial year) on a nearly circular orbit at a mean orbital distance of 0.1514 AU.

Transit Fingerprint

Depth

0.087 %

Duration

3.780 h

Impact parameter b

0.120

Rp / R★

0.029470

Transit midpoint (BJD)

2,458,868.8152

Photometric dip

Transit produces a flux drop of 868 ppm lasting ≈ 3.78 h.

Extended Orbital Architecture

Planet / star radius ratio

0.029470

Semi-major axis / stellar radius

60.350

Impact parameter (b)

0.120

RV semi-amplitude (K)

1.820 m/s

Transit mid-time (BJD)

2,458,868.8152

Long. of periastron (ω)

263.00°

Angular separation (arcsec)

4.24000

Eq. Temperature

333K

(60 °C)

Insolation (S⊕)

2.05

Earth = 1.00

Earth Similarity (ESI)

0.799

0 = alien, 1 = Earth-identical

Inside the inner HZ boundary (too hot for liquid water) — liquid water is physically possible with adequate atmospheric pressure. 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

Teledyne e2v CCD detector

Publication

2026-02

Observation locale

Space

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