TOI-1680 b
TOI-1680 b is a super-Earth orbiting the M4.5+/-0.5 star TOI-1680 in the constellation Draco. It lies about 121 light-years from Earth and was discovered in 2023 using the transit method.
How Big Is TOI-1680 b?
TOI-1680 b has a radius of 1.47 times that of Earth.
Is TOI-1680 b in the Habitable Zone?
TOI-1680 b orbits inside the inner edge of the habitable zone of TOI-1680. So close to its star, surface conditions are far too hot for liquid water.
Habitable zone of TOI-1680: 0.054–0.142 AU (conservative: 0.068–0.135 AU), per Kopparapu et al. (2014). Earth orbits the Sun at 1 AU.
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Temperature on TOI-1680 b
The equilibrium temperature of TOI-1680 b is about 404 K (131 °C) — hotter than anywhere on Earth. This estimate ignores any atmosphere, which could change surface temperatures dramatically — Earth's greenhouse effect adds about 33 °C. It receives 4.41 times the stellar energy that Earth gets from the Sun.
Orbit and Year Length
A year on TOI-1680 b — one full orbit around TOI-1680 — lasts 4.80 Earth days, shorter than Mercury's 88-day year. It orbits at an average distance of 0.031 AU — closer to its star than Mercury is to the Sun.
How Was TOI-1680 b Discovered?
TOI-1680 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-1680 b?
TOI-1680 b is 121.4 light-years (37.2 parsecs) from Earth. Light arriving here tonight left the planet around the year 1905. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 2,136,640 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-1680 b scores 0.54, ranking #212 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: TOI-1680
TOI-1680
- Spectral type
- M4.5+/-0.5
- Surface temperature
- 3,225 K (Sun: 5,772 K)
- Mass
- 0.18 M☉
- Radius
- 0.21 R☉
- Luminosity
- 0.0043 L☉
Planetary System
TOI-1680 b is the only planet known to orbit TOI-1680 so far.
TOI-1680 b — Complete Data
| Radius | 1.466 Earth radii (0.131 Jupiter radii) |
|---|---|
| Orbital period | 4.80 days |
| Orbital distance | 0.031 AU |
| Equilibrium temperature | 404 K (131 °C) |
| Stellar irradiation | 4.41× Earth |
| Earth Similarity Index | 0.54 |
| Distance from Earth | 121.4 light-years (37.2 parsecs) |
| Constellation | Draco |
| Discovery method | Transit |
| Discovery facility | Transiting Exoplanet Survey Satellite (TESS) |
| Discovery year | 2023 |
Data: NASA Exoplanet Archive, last updated 2023-07-21. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About TOI-1680 b
Is TOI-1680 b habitable?
No — TOI-1680 b orbits too close to its star and is too hot for liquid water to exist on its surface.
How far away is TOI-1680 b?
TOI-1680 b is about 121 light-years from Earth in the constellation Draco. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 2,136,640 years to get there.
How big is TOI-1680 b compared to Earth?
TOI-1680 b has 1.47 times the radius of Earth.
How long is a year on TOI-1680 b?
One orbit around TOI-1680 takes 4.8 Earth days — short enough that 76 of its years would fit into one Earth year.
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