Key parameters at a glance

A radius of 1.37 Earth radii
A mass of 25.30 Earth masses
Surface gravity around 13.54 g
An orbital period of 8.457 days
Semi-major axis 0.0398 AU
Equilibrium temperature 272 K (-1 °C)
Distance from Earth 105.77 light-years
Earth Similarity Index 0.731
Travel time at Voyager 1 speed 1,865,285 years
Almost certainly tidally locked to its host star given the close orbit

Context from the literature

LP 890-9, also known as SPECULOOS-2 or TOI-4306, is a high proper motion red dwarf star located 105 light-years (32 pc) away from the Solar System in the constellation of Eridanus. The star has 12% the mass and 15% the radius of the Sun, and a temperature of 2,871 K. It is extremely faint and, with an apparent magnitude of 18, is the faintest star with exoplanets discovered by the Transiting Exoplanet Survey Satellite.

Excerpted from Wikipedia · full article

1 sibling around LP 890-9

LP 890-9 c 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
LP 890-9 b	Super-Earth	1.32	13.20	2.730	396	2022
LP 890-9 c this	Super-Earth	1.37	25.30	8.457	272	2022

LP 890-9 c Planet Profile

Physical Specs

Radius

1.37 R⊕

Radius (Jupiter)

0.122 R♃

Mass

25.30 M⊕

Mass (Jupiter)

0.080 M♃

Density

— g/cm³

Surface Gravity

13.54 g (Earth)

Classification

Planet Type

Super-Earth

ESI Score 0.731

HZ Position Habitable

Controversial No

Discovery

Year 2022

Method Transit

Facility SPECULOOS Southern Observatory

Telescope Multiple Telescopes

Size rank in cohort

Rank by radius

#976of 1176

top 82.9%

This planet

1.37R⊕

Super-Earth median

1.60R⊕

Nearest-size peers

K2-200 b 1.36 R⊕ Kepler-286 c 1.37 R⊕ Kepler-240 b 1.37 R⊕

Metric	Earth	LP 890-9 c	Jupiter
Radius (R⊕)	1.00	1.37	11.21
Mass (M⊕)	1.00	25.30	317.83
Density (g/cm³)	5.51	—	1.33
Surface Gravity (g)	1.00	13.54	2.53
Insolation (S⊕)	1.00	0.91	0.037

Alternative Mass Estimates

Method	Value	Interpretation
Best measured mass	25.300 M⊕	Direct mass measurement (not derived).

Star Catalogue Identifiers

TIC

TIC 44898913

Gaia DR2

Gaia DR2 4886243456388510720

Gaia DR3

Gaia DR3 4886243456388510720

System

LP 890-9

Percentile among Super-Earth cohort

Radius 1.367 R⊕ · percentile 17 / cohort 1176

Mass 25.300 M⊕ · percentile 98 / cohort 1176

Orbital period 8.46 d · percentile 59 / cohort 1164

Distance 32.43 pc · percentile 7 / cohort 1171

ESI 0.731 · percentile 86 / cohort 1176

Orbit & Habitability

Orbital Dynamics

Period

8.457 days

Semi-major axis

0.0398 AU

Eccentricity

—

Inclination

89.29 °

Year Length

A year here lasts approximately 8.46 Earth days (2.3% of a terrestrial year) at a mean orbital distance of 0.0398 AU.

Transit Fingerprint

Depth

0.666 %

Duration

0.959 h

Impact parameter b

0.697

Transit midpoint (BJD)

2,459,520.7060

Photometric dip

Transit produces a flux drop of 6,659 ppm lasting ≈ 0.96 h.

Extended Orbital Architecture

Semi-major axis / stellar radius

55.940

Impact parameter (b)

0.697

RV semi-amplitude (K)

33.000 m/s

Transit mid-time (BJD)

2,459,520.7060

Angular separation (arcsec)

1.23000

Eq. Temperature

272K

(-1 °C)

Insolation (S⊕)

0.91

Earth = 1.00

Earth Similarity (ESI)

0.731

0 = alien, 1 = Earth-identical

Within the conservative habitable zone — surface water would be frozen. Close-orbiting tidally-locked around a cool host.

Discovery Paper

Primary reference

Delrez et al. 2022

Instrument

Multiple Instruments

Publication

2022-09

Observation locale

Ground

Host System: LP 890-9

Spectral Class

M-type red dwarf

Effective Temperature

2,850 K — cooler than the Sun (5,778 K)

Estimated Age

7.20 Gyr — older than the Sun (4.6 Gyr)

Stellar Radius

0.156 R☉

Stellar Mass

0.118 M☉

Metallicity [Fe/H]

-0.03

Extended Stellar Properties

Surface gravity (log g)

5.126 dex

Stellar density

44.200 g/cm³

Systemic radial velocity

27.94 km/s

Metallicity ratio

[Fe/H]

Distance

32.43 parsec

Light-years 105.77 ly

V-band magnitude

18.00 mag

Voyager-speed travel 1,865,285 yr

Multi-band Host Photometry — 6 bands

Astrometric Data

Parallax

30.807 mas

Total Proper Motion

332.902 mas/yr

PM Right Ascension

218.53 mas/yr

PM Declination

-251.13 mas/yr

Galactic Cartesian (pc)

x = 0.384 · y = 0.792 · z = -0.474

Equatorial (J2000)

RA 64.13091° · Dec -28.31579°

Galactic ℓ, b

226.914° · -44.948°

Ecliptic λ, β

54.475° · -48.615°

HTM-20 index

-217062951

Wikipedia →