Key parameters at a glance

A radius of 0.95 Earth radii
A mass of 0.82 Earth masses
Surface gravity around 0.90 g
An orbital period of 26.130 days
Semi-major axis 0.0791 AU
Equilibrium temperature 159 K (-114 °C)
Distance from Earth 12.49 light-years
Earth Similarity Index 0.611
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 is an M-type red dwarf star in the constellation Aries, 12.5 light-years from the Solar System. Although it is near Earth it is a dim magnitude 15 and can only be seen through large telescopes. This star was found to have a very large proper motion of about 5 arcseconds per year. Only seven stars with such large proper motions are currently known. Teegarden's Star hosts a planetary system with at least three planets.

Excerpted from Wikipedia · full article

2 siblings around Teegarden's Star

Teegarden's Star d 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	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 this	Rocky Terrestrial	0.95	0.82	26.130	159	2024

Teegarden's Star d Planet Profile

Physical Specs

Radius

0.95 R⊕

Radius (Jupiter)

0.085 R♃

Mass

0.82 M⊕

Mass (Jupiter)

0.003 M♃

Density

5.19 g/cm³

Surface Gravity

0.90 g (Earth)

Classification

Planet Type

Rocky Terrestrial

ESI Score 0.611

HZ Position Outer

Controversial No

Discovery

Year 2024

Method Radial Velocity

Facility Multiple Observatories

Telescope Multiple Telescopes

Size rank in cohort

Rank by radius

#373of 570

top 65.3%

This planet

0.95R⊕

Rocky Terrestrial median

1.01R⊕

Nearest-size peers

TOI-700 e 0.95 R⊕ HD 101581 b 0.96 R⊕ Kepler-20 f 0.95 R⊕

Metric	Earth	Teegarden's Star d	Jupiter
Radius (R⊕)	1.00	0.95	11.21
Mass (M⊕)	1.00	0.82	317.83
Density (g/cm³)	5.51	5.19	1.33
Surface Gravity (g)	1.00	0.90	2.53
Insolation (S⊕)	1.00	0.12	0.037

Alternative Mass Estimates

Method	Value	Interpretation
Minimum mass (M sin i)	0.820 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 0.954 R⊕ · percentile 35 / cohort 570

Mass 0.820 M⊕ · percentile 30 / cohort 570

Orbital period 26.13 d · percentile 95 / cohort 567

Distance 3.83 pc · percentile 2 / cohort 566

ESI 0.611 · percentile 79 / cohort 570

Orbit & Habitability

Orbital Dynamics

Period

26.130 days

Semi-major axis

0.0791 AU

Eccentricity

0.070

Inclination

— °

Year Length

A year here lasts approximately 26.13 Earth days (7.2% of a terrestrial year) on a nearly circular orbit at a mean orbital distance of 0.0791 AU.

Eq. Temperature

159K

(-114 °C)

Insolation (S⊕)

0.12

Earth = 1.00

Earth Similarity (ESI)

0.611

0 = alien, 1 = Earth-identical

Beyond the outer HZ boundary (too cold) — surface water would be frozen. Close-orbiting tidally-locked around a cool host.

Discovery Paper

Primary reference

Dreizler et al. 2024

Instrument

Multiple Instruments

Publication

2024-02

Observation locale

Ground

Discovery cohort

Planets confirmed in 2024 at Multiple Observatories (12 shown).

HD 134606 e · Super-Earth Kepler-51 e · Sub-Neptune HD 134606 f · Sub-Neptune HD 134606 b · Sub-Neptune HD 134606 c · Sub-Neptune HD 104067 c · Sub-Neptune GJ 1289 b · Sub-Neptune TOI-4562 c · Gas Giant HD 222237 b · Gas Giant CI Tau c · Gas Giant HD 75898 c · Gas Giant GJ 900 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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