TOI-778 b
TOI-778 b is a hot Jupiter orbiting the F3 V star TOI-778 in the constellation Virgo. It lies about 528 light-years from Earth and was discovered in 2023 using the transit method.
How Big Is TOI-778 b?
TOI-778 b has a radius of 15.40 times that of Earth, or 1.37 times the radius of Jupiter. Its mass is 878 times that of Earth, giving it a density of 1.30 g/cm³ — closer to gas planets like Jupiter (1.33 g/cm³).
Is TOI-778 b in the Habitable Zone?
TOI-778 b orbits inside the inner edge of the habitable zone of TOI-778. So close to its star, surface conditions are far too hot for liquid water.
Habitable zone of TOI-778: 1.710–3.962 AU (conservative: 2.166–3.757 AU), per Kopparapu et al. (2014). Earth orbits the Sun at 1 AU.
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Temperature on TOI-778 b
The equilibrium temperature of TOI-778 b is about 1,561 K (1,288 °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.
Orbit and Year Length
A year on TOI-778 b — one full orbit around TOI-778 — lasts 4.63 Earth days, shorter than Mercury's 88-day year. It orbits at an average distance of 0.060 AU — closer to its star than Mercury is to the Sun. Its orbit is mildly elliptical (eccentricity 0.21).
How Was TOI-778 b Discovered?
TOI-778 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-778 b?
TOI-778 b is 527.5 light-years (161.7 parsecs) from Earth. Light arriving here tonight left the planet around the year 1499. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 9,284,000 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-778 b scores 0.06, ranking #5,150 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: TOI-778
TOI-778
- Spectral type
- F3 V
- Surface temperature
- 6,643 K (Sun: 5,772 K)
- Mass
- 1.40 M☉
- Radius
- 1.71 R☉
- Luminosity
- 5.7600 L☉
- Age
- 2.0 billion years (Sun: 4.6)
Planetary System
TOI-778 b is the only planet known to orbit TOI-778 so far.
TOI-778 b — Complete Data
| Radius | 15.400 Earth radii (1.370 Jupiter radii) |
|---|---|
| Mass | 878.00 Earth masses (2.800 Jupiter masses) |
| Density | 1.30 g/cm³ (Earth: 5.51) |
| Orbital period | 4.63 days |
| Orbital distance | 0.060 AU |
| Eccentricity | 0.210 |
| Equilibrium temperature | 1,561 K (1,288 °C) |
| Earth Similarity Index | 0.06 |
| Distance from Earth | 527.5 light-years (161.7 parsecs) |
| Constellation | Virgo |
| Discovery method | Transit |
| Discovery facility | Transiting Exoplanet Survey Satellite (TESS) |
| Discovery year | 2023 |
Data: NASA Exoplanet Archive, last updated 2023-05-03. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About TOI-778 b
Is TOI-778 b habitable?
No — TOI-778 b orbits too close to its star and is too hot for liquid water to exist on its surface.
How far away is TOI-778 b?
TOI-778 b is about 528 light-years from Earth in the constellation Virgo. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 9,284,000 years to get there.
How big is TOI-778 b compared to Earth?
TOI-778 b has 15.40 times the radius of Earth and about 878 times its mass.
How long is a year on TOI-778 b?
One orbit around TOI-778 takes 4.6 Earth days — short enough that 79 of its years would fit into one Earth year.
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