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Stars · exoplanets

Teegarden's Star: a tiny star with Earth-mass planets

Teegarden's Star, a small orange-red star, with one of its planets beside it, drawn in Exo-View

Teegarden's Star is a tiny red dwarf, 12.5 light-years away, a tenth the Sun's width and far too faint to see without a big telescope. It was found only in 2003, and in 2019 two planets of about the Earth's mass were found going round it, one of them getting almost exactly as much light as the Earth does. Exo-View flies you there.

Fly to Teegarden's StarSee the Milky Way
Distance
12.5 light-years, in the constellation Aries
Kind
Red dwarf, spectral type M7
Size
0.11 times the Sun's width, about as wide as Jupiter
Surface temperature
About 2,900 K
Brightness
Magnitude 15: about four thousand times fainter than the faintest star the naked eye can see
Planets
Teegarden's Star b, 4.9 days; c, 11.4 days

A star that was missed

Teegarden's Star is one of the nearest stars to the Sun, and yet it went unnoticed until 2003, when Bonnie Teegarden and colleagues found it moving quickly across the sky in images from a survey looking for asteroids. It is so faint that it gives out only about a thousandth of the Sun's light, mostly as infrared.

Two planets

In 2019 a team using the CARMENES instrument in Spain found two planets by the tiny wobbles they cause in the star's motion. Planet b has at least about the Earth's mass and goes round in under five days. Because the star is so dim, it is close in but gets about as much light as the Earth does, which put it high on the list of the most Earth-like planets known when it was found. Planet c, further out, would be colder. No one knows whether either has air or water.

In Exo-View

The button below flies from the Sun to Teegarden's Star. Its planets are drawn in their orbits as an illustration made from their figures: nobody has a picture of an exoplanet, and the plates say so.

Fly to Teegarden's StarSee the Milky Way

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