TOI-815 b
TOI-815 b is a mini-Neptune orbiting the K3 V star TOI-815 in the constellation Vela. It lies about 195 light-years from Earth and was discovered in 2024 using the transit method.
How Big Is TOI-815 b?
TOI-815 b has a radius of 2.94 times that of Earth. Its mass is 7.6 times that of Earth, giving it a density of 1.64 g/cm³ — closer to gas planets like Jupiter (1.33 g/cm³).
Is TOI-815 b in the Habitable Zone?
TOI-815 b orbits inside the inner edge of the habitable zone of TOI-815. So close to its star, surface conditions are far too hot for liquid water.
Habitable zone of TOI-815: 0.431–1.047 AU (conservative: 0.546–0.993 AU), per Kopparapu et al. (2014). Earth orbits the Sun at 1 AU.
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Temperature on TOI-815 b
The equilibrium temperature of TOI-815 b is about 686 K (413 °C) — hot enough to melt many metals. This estimate ignores any atmosphere, which could change surface temperatures dramatically — Earth's greenhouse effect adds about 33 °C. It receives 36.90 times the stellar energy that Earth gets from the Sun.
Orbit and Year Length
A year on TOI-815 b — one full orbit around TOI-815 — lasts 11.2 Earth days, shorter than Mercury's 88-day year. It orbits at an average distance of 0.090 AU — closer to its star than Mercury is to the Sun. Its orbit is mildly elliptical (eccentricity 0.20).
How Was TOI-815 b Discovered?
TOI-815 b was discovered in 2024 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-815 b?
TOI-815 b is 194.8 light-years (59.7 parsecs) from Earth. Light arriving here tonight left the planet around the year 1832. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 3,428,480 years to make the journey.
The Host Star: TOI-815
TOI-815 b belongs to a system of 2 stars; it orbits TOI-815.
TOI-815
- Spectral type
- K3 V
- Surface temperature
- 4,869 K (Sun: 5,772 K)
- Mass
- 0.78 M☉
- Radius
- 0.77 R☉
- Age
- 0.2 billion years (Sun: 4.6)
The TOI-815 Planetary System
TOI-815 b is one of 2 known planets in the TOI-815 system. Its siblings:
- TOI-815 c (Super Earth)
TOI-815 b — Complete Data
| Radius | 2.940 Earth radii (0.262 Jupiter radii) |
|---|---|
| Mass | 7.60 Earth masses (0.024 Jupiter masses) |
| Density | 1.64 g/cm³ (Earth: 5.51) |
| Orbital period | 11.20 days |
| Orbital distance | 0.090 AU |
| Eccentricity | 0.200 |
| Equilibrium temperature | 686 K (413 °C) |
| Stellar irradiation | 36.90× Earth |
| Distance from Earth | 194.8 light-years (59.7 parsecs) |
| Constellation | Vela |
| Discovery method | Transit |
| Discovery facility | Transiting Exoplanet Survey Satellite (TESS) |
| Discovery year | 2024 |
Data: NASA Exoplanet Archive, last updated 2024-05-13. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About TOI-815 b
Is TOI-815 b habitable?
No — TOI-815 b orbits too close to its star and is too hot for liquid water to exist on its surface.
How far away is TOI-815 b?
TOI-815 b is about 195 light-years from Earth in the constellation Vela. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 3,428,480 years to get there.
How big is TOI-815 b compared to Earth?
TOI-815 b has 2.94 times the radius of Earth and about 7.6 times its mass.
How long is a year on TOI-815 b?
One orbit around TOI-815 takes 11.2 Earth days — short enough that 33 of its years would fit into one Earth year.
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