Teegarden's Star c
Teegarden's Star c is a terrestrial planet orbiting Teegarden's Star in the constellation Aries. It lies about 13 light-years from Earth and was discovered in 2019 using the radial velocity method. It orbits within the habitable zone of its star — the region where liquid water could exist on a planet's surface.
Is Teegarden's Star c in the Habitable Zone?
Teegarden's Star c orbits inside the conservative habitable zone of Teegarden's Star — the region where a rocky planet could sustain liquid water on its surface. This makes it one of the most interesting known exoplanets in the search for life.
Habitable zone of Teegarden's Star: 0.022–0.059 AU (conservative: 0.028–0.056 AU), per Kopparapu et al. (2014). Earth orbits the Sun at 1 AU.
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Temperature on Teegarden's Star c
The equilibrium temperature of Teegarden's Star c is about 209 K (-64 °C) — well below freezing. This estimate ignores any atmosphere, which could change surface temperatures dramatically — Earth's greenhouse effect adds about 33 °C. It receives 0.35 times the stellar energy that Earth gets from the Sun.
Orbit and Year Length
A year on Teegarden's Star c — one full orbit around Teegarden's Star — lasts 11.4 Earth days, shorter than Mercury's 88-day year. It orbits at an average distance of 0.046 AU — closer to its star than Mercury is to the Sun. Its orbit is nearly circular (eccentricity 0.040).
How Was Teegarden's Star c Discovered?
Teegarden's Star c was discovered in 2019 using the radial velocity method, with observations from Calar Alto Observatory.
The radial velocity method measures the subtle wobble of a star caused by the gravitational pull of an orbiting planet, visible as periodic shifts in the star's light spectrum. The size of the wobble reveals the planet's minimum mass.
How Far Away Is Teegarden's Star c?
Teegarden's Star c is 12.5 light-years (3.8 parsecs) from Earth. Light arriving here tonight left the planet around the year 2014. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 220,000 years to make the journey.
Earth Similarity Index
The Earth Similarity Index (ESI) scores how physically similar a planet is to Earth, from 0 to 1, based on radius, density, escape velocity and surface temperature. Teegarden's Star c scores 0.66, ranking #85 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: Teegarden's Star
Teegarden's Star
- Surface temperature
- 3,034 K (Sun: 5,772 K)
- Mass
- 0.10 M☉
- Radius
- 0.12 R☉
- Luminosity
- 0.0007 L☉
The Teegarden's Star Planetary System
Teegarden's Star c is one of 3 known planets in the Teegarden's Star system. Its siblings:
- Teegarden's Star b (Terrestrial)
- Teegarden's Star d (Terrestrial)
Teegarden's Star c — Complete Data
| Mass (best estimate) | 1.05 Earth masses |
|---|---|
| Orbital period | 11.42 days |
| Orbital distance | 0.046 AU |
| Eccentricity | 0.040 |
| Equilibrium temperature | 209 K (-64 °C) |
| Stellar irradiation | 0.35× Earth |
| Earth Similarity Index | 0.66 |
| Distance from Earth | 12.5 light-years (3.8 parsecs) |
| Constellation | Aries |
| Discovery method | Radial Velocity |
| Discovery facility | Calar Alto Observatory |
| Discovery year | 2019 |
Data: NASA Exoplanet Archive, last updated 2024-03-05. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About Teegarden's Star c
Is Teegarden's Star c habitable?
Teegarden's Star c orbits within the habitable zone of Teegarden's Star, the region where liquid water could exist on a planet's surface. It sits in the conservative habitable zone — the most promising region for habitability. Whether it is actually habitable depends on its atmosphere and composition, which remain unknown.
How far away is Teegarden's Star c?
Teegarden's Star c is about 13 light-years from Earth in the constellation Aries. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 220,000 years to get there.
How long is a year on Teegarden's Star c?
One orbit around Teegarden's Star takes 11.4 Earth days — short enough that 32 of its years would fit into one Earth year.
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