TOI-715 b
TOI-715 b is a super-Earth orbiting the M4 star TOI-715 in the constellation Volans. It lies about 138 light-years from Earth and was discovered in 2023 using the transit method. It orbits within the habitable zone of its star — the region where liquid water could exist on a planet's surface.
How Big Is TOI-715 b?
TOI-715 b has a radius of 1.55 times that of Earth.
Is TOI-715 b in the Habitable Zone?
TOI-715 b orbits inside the conservative habitable zone of TOI-715 — 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 TOI-715: 0.056–0.148 AU (conservative: 0.071–0.140 AU), per Kopparapu et al. (2014). Earth orbits the Sun at 1 AU.
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Temperature on TOI-715 b
The equilibrium temperature of TOI-715 b is about 234 K (-39 °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 0.67 times the stellar energy that Earth gets from the Sun.
Orbit and Year Length
A year on TOI-715 b — one full orbit around TOI-715 — lasts 19.3 Earth days, shorter than Mercury's 88-day year. It orbits at an average distance of 0.083 AU — closer to its star than Mercury is to the Sun.
How Was TOI-715 b Discovered?
TOI-715 b was discovered in 2023 using the transit method, with observations from Transiting Exoplanet Survey Satellite (TESS).
The transit method watches a star for the tiny, regular dip in brightness that occurs when a planet crosses in front of it. The depth and timing of these dips reveal the planet's size and orbital period.
How Far Away Is TOI-715 b?
TOI-715 b is 138.3 light-years (42.4 parsecs) from Earth. Light arriving here tonight left the planet around the year 1888. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 2,434,080 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. TOI-715 b scores 0.81, ranking #24 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: TOI-715
TOI-715
- Spectral type
- M4
- Surface temperature
- 3,075 K (Sun: 5,772 K)
- Mass
- 0.23 M☉
- Radius
- 0.24 R☉
- Age
- 6.2 billion years (Sun: 4.6)
Planetary System
TOI-715 b is the only planet known to orbit TOI-715 so far.
TOI-715 b — Complete Data
| Radius | 1.550 Earth radii (0.138 Jupiter radii) |
|---|---|
| Orbital period | 19.29 days |
| Orbital distance | 0.083 AU |
| Equilibrium temperature | 234 K (-39 °C) |
| Stellar irradiation | 0.67× Earth |
| Earth Similarity Index | 0.81 |
| Distance from Earth | 138.3 light-years (42.4 parsecs) |
| Constellation | Volans |
| Discovery method | Transit |
| Discovery facility | Transiting Exoplanet Survey Satellite (TESS) |
| Discovery year | 2023 |
Data: NASA Exoplanet Archive, last updated 2023-05-26. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About TOI-715 b
Is TOI-715 b habitable?
TOI-715 b orbits within the habitable zone of TOI-715, 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 TOI-715 b?
TOI-715 b is about 138 light-years from Earth in the constellation Volans. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 2,434,080 years to get there.
How big is TOI-715 b compared to Earth?
TOI-715 b has 1.55 times the radius of Earth.
How long is a year on TOI-715 b?
One orbit around TOI-715 takes 19.3 Earth days — short enough that 19 of its years would fit into one Earth year.
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