TOI-677 b
TOI-677 b is a cold gas giant orbiting the F8 star TOI-677 in the constellation Vela. It lies about 463 light-years from Earth and was discovered in 2020 using the transit method.
How Big Is TOI-677 b?
TOI-677 b has a radius of 13.11 times that of Earth, or 1.17 times the radius of Jupiter. Its mass is 392 times that of Earth.
Is TOI-677 b in the Habitable Zone?
TOI-677 b orbits inside the inner edge of the habitable zone of TOI-677. So close to its star, surface conditions are far too hot for liquid water.
Habitable zone of TOI-677: 1.105–2.573 AU (conservative: 1.400–2.440 AU), per Kopparapu et al. (2014). Earth orbits the Sun at 1 AU.
See the full interactive habitable-zone view in the Exoplanet Explorer app ›
Orbit and Year Length
A year on TOI-677 b — one full orbit around TOI-677 — lasts 11.2 Earth days, shorter than Mercury's 88-day year. It orbits at an average distance of 0.104 AU — closer to its star than Mercury is to the Sun. Its orbit is highly elliptical (eccentricity 0.46), swinging dramatically closer to and farther from its star.
How Was TOI-677 b Discovered?
TOI-677 b was discovered in 2020 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-677 b?
TOI-677 b is 462.5 light-years (141.8 parsecs) from Earth. Light arriving here tonight left the planet around the year 1564. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 8,140,000 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. TOI-677 b scores 0.07, ranking #4,850 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: TOI-677
TOI-677
- Spectral type
- F8
- Surface temperature
- 6,295 K (Sun: 5,772 K)
- Mass
- 1.18 M☉
- Radius
- 1.28 R☉
- Age
- 2.9 billion years (Sun: 4.6)
Planetary System
TOI-677 b is the only planet known to orbit TOI-677 so far.
TOI-677 b — Complete Data
| Radius | 13.115 Earth radii (1.170 Jupiter radii) |
|---|---|
| Mass | 392.20 Earth masses (1.234 Jupiter masses) |
| Orbital period | 11.24 days |
| Orbital distance | 0.104 AU |
| Eccentricity | 0.460 |
| Earth Similarity Index | 0.07 |
| Distance from Earth | 462.5 light-years (141.8 parsecs) |
| Constellation | Vela |
| Discovery method | Transit |
| Discovery facility | Transiting Exoplanet Survey Satellite (TESS) |
| Discovery year | 2020 |
Data: NASA Exoplanet Archive, last updated 2025-03-21. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About TOI-677 b
Is TOI-677 b habitable?
No — TOI-677 b orbits too close to its star and is too hot for liquid water to exist on its surface.
How far away is TOI-677 b?
TOI-677 b is about 463 light-years from Earth in the constellation Vela. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 8,140,000 years to get there.
How big is TOI-677 b compared to Earth?
TOI-677 b has 13.11 times the radius of Earth and about 392 times its mass.
How long is a year on TOI-677 b?
One orbit around TOI-677 takes 11.2 Earth days — short enough that 33 of its years would fit into one Earth year.
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