Key parameters at a glance

A radius of 1.05 Earth radii
A mass of 1.16 Earth masses
Surface gravity around 1.05 g
An orbital period of 4.906 days
Semi-major axis 0.0259 AU
Equilibrium temperature 277 K (4 °C)
Distance from Earth 12.49 light-years
Earth Similarity Index 0.965
Travel time at Voyager 1 speed 220,337 years
Almost certainly tidally locked to its host star given the close orbit

Context from the literature

Teegarden's Star b is an exoplanet found orbiting within the habitable zone of Teegarden's Star, an M-type red dwarf 12.5 light-years away from the Solar System. It had the highest Earth Similarity Index (ESI) of any exoplanet, but in February 2024 a new study updated the parameters of the planet, thus reducing its ESI to 0.90, making it no longer the planet with the hightest ESI. Along with Teegarden's Star c, it is among the closest-known potentially habitable exoplanets.

Excerpted from Wikipedia · full article

2 siblings around Teegarden's Star

Teegarden's Star b shares its host star with 2 other confirmed planets. Side-by-side measurements below.

Planet	Type	Radius (R⊕)	Mass (M⊕)	Period (d)	Eq. T (K)	Year
Teegarden's Star b this	Rocky Terrestrial	1.05	1.16	4.906	277	2019
Teegarden's Star c	Rocky Terrestrial	1.02	1.05	11.416	209	2019
Teegarden's Star d	Rocky Terrestrial	0.95	0.82	26.130	159	2024

Teegarden's Star b Planet Profile

Physical Specs

Radius

1.05 R⊕

Radius (Jupiter)

0.094 R♃

Mass

1.16 M⊕

Mass (Jupiter)

0.004 M♃

Density

5.51 g/cm³

Surface Gravity

1.05 g (Earth)

Classification

Planet Type

Rocky Terrestrial

ESI Score 0.965

HZ Position Habitable

Controversial No

Discovery

Year 2019

Method Radial Velocity

Facility Calar Alto Observatory

Telescope 3.5 m telescope

Size rank in cohort

Rank by radius

#279of 570

top 48.8%

This planet

1.05R⊕

Rocky Terrestrial median

1.01R⊕

Nearest-size peers

Kepler-1331 b 1.05 R⊕ Kepler-1376 b 1.05 R⊕ Kepler-163 b 1.05 R⊕

Metric	Earth	Teegarden's Star b	Jupiter
Radius (R⊕)	1.00	1.05	11.21
Mass (M⊕)	1.00	1.16	317.83
Density (g/cm³)	5.51	5.51	1.33
Surface Gravity (g)	1.00	1.05	2.53
Insolation (S⊕)	1.00	1.08	0.037

Alternative Mass Estimates

Method	Value	Interpretation
Minimum mass (M sin i)	1.160 M⊕	Lower bound from radial-velocity fitting.

Star Catalogue Identifiers

TIC

TIC 257870150

Gaia DR2

Gaia DR2 35227046884571776

Gaia DR3

Gaia DR3 35227046884571776

System

Teegarden's Star

Percentile among Rocky Terrestrial cohort

Radius 1.050 R⊕ · percentile 50 / cohort 570

Mass 1.160 M⊕ · percentile 45 / cohort 570

Orbital period 4.91 d · percentile 53 / cohort 567

Distance 3.83 pc · percentile 2 / cohort 566

ESI 0.965 · percentile 96 / cohort 570

Orbit & Habitability

Orbital Dynamics

Period

4.906 days

Semi-major axis

0.0259 AU

Eccentricity

0.030

Inclination

— °

Year Length

A year here lasts approximately 4.91 Earth days (1.3% of a terrestrial year) on a nearly circular orbit at a mean orbital distance of 0.0259 AU.

Eq. Temperature

277K

(4 °C)

Insolation (S⊕)

1.08

Earth = 1.00

Earth Similarity (ESI)

0.965

0 = alien, 1 = Earth-identical

Within the conservative habitable zone — liquid water is physically possible with adequate atmospheric pressure. Close-orbiting tidally-locked around a cool host.

Discovery Paper

Primary reference

Zechmeister et al. 2019

Instrument

CARMENES

Publication

2019-07

Observation locale

Ground

Discovery cohort

Planets confirmed in 2019 at Calar Alto Observatory (4 shown).

Teegarden's Star c · Rocky Terrestrial LSPM J2116+0234 b · Sub-Neptune GJ 4276 b · Neptune-like GJ 3512 b · Gas Giant

Host System: Teegarden's Star

Spectral Class

M-type red dwarf

Effective Temperature

3,034 K — cooler than the Sun (5,778 K)

Estimated Age

8.00 Gyr — older than the Sun (4.6 Gyr)

Stellar Radius

0.120 R☉

Stellar Mass

0.097 M☉

Metallicity [Fe/H]

-0.11

Extended Stellar Properties

Surface gravity (log g)

5.190 dex

Stellar density

79.807 g/cm³

Rotational v·sin i

2.00 km/s

Rotation period

96.20 days

Metallicity ratio

[Fe/H]

Distance

3.83 parsec

Light-years 12.49 ly

V-band magnitude

15.13 mag

Voyager-speed travel 220,337 yr

Multi-band Host Photometry — 6 bands

Astrometric Data

Parallax

261.015 mas

Total Proper Motion

5,123.332 mas/yr

PM Right Ascension

3,429.53 mas/yr

PM Declination

-3,806.16 mas/yr

Galactic Cartesian (pc)

x = 0.697 · y = 0.656 · z = 0.290

Equatorial (J2000)

RA 43.26914° · Dec 16.86490°

Galactic ℓ, b

160.290° · -37.031°

Ecliptic λ, β

45.822° · 0.301°

HTM-20 index

-1746316371

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