TOI-3278 b
TOI-3278 b is a hot Jupiter orbiting the G2-G4 V star TOI-3278 in the constellation Pavo. It lies about 2,951 light-years from Earth and was discovered in 2026 using the transit method.
How Big Is TOI-3278 b?
TOI-3278 b has a radius of 13.90 times that of Earth, or 1.24 times the radius of Jupiter. Its mass is 95.3 times that of Earth, giving it a density of 0.21 g/cm³ — closer to gas planets like Jupiter (1.33 g/cm³).
Is TOI-3278 b in the Habitable Zone?
TOI-3278 b orbits inside the inner edge of the habitable zone of TOI-3278. So close to its star, surface conditions are far too hot for liquid water.
Habitable zone of TOI-3278: 1.026–2.421 AU (conservative: 1.299–2.295 AU), per Kopparapu et al. (2014). Earth orbits the Sun at 1 AU.
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Temperature on TOI-3278 b
The equilibrium temperature of TOI-3278 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. It receives 1,030 times the stellar energy that Earth gets from the Sun.
Orbit and Year Length
A year on TOI-3278 b — one full orbit around TOI-3278 — lasts 3.25 Earth days, shorter than Mercury's 88-day year. It orbits at an average distance of 0.043 AU — closer to its star than Mercury is to the Sun.
How Was TOI-3278 b Discovered?
TOI-3278 b was discovered in 2026 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-3278 b?
TOI-3278 b is 2,950.9 light-years (904.8 parsecs) from Earth. Light arriving here tonight left the planet about 2,951 years ago. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 51,935,840 years to make the journey.
The Host Star: TOI-3278
TOI-3278
- Spectral type
- G2-G4 V
- Surface temperature
- 5,720 K (Sun: 5,772 K)
- Mass
- 1.04 M☉
- Radius
- 1.39 R☉
- Age
- 8.9 billion years (Sun: 4.6)
Planetary System
TOI-3278 b is the only planet known to orbit TOI-3278 so far.
TOI-3278 b — Complete Data
| Radius | 13.899 Earth radii (1.240 Jupiter radii) |
|---|---|
| Mass | 95.35 Earth masses (0.300 Jupiter masses) |
| Density | 0.21 g/cm³ (Earth: 5.51) |
| Orbital period | 3.25 days |
| Orbital distance | 0.043 AU |
| Equilibrium temperature | 1,561 K (1,288 °C) |
| Stellar irradiation | 1,030.00× Earth |
| Distance from Earth | 2,950.9 light-years (904.8 parsecs) |
| Constellation | Pavo |
| Discovery method | Transit |
| Discovery facility | Transiting Exoplanet Survey Satellite (TESS) |
| Discovery year | 2026 |
Data: NASA Exoplanet Archive, last updated 2026-09-03. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About TOI-3278 b
Is TOI-3278 b habitable?
No — TOI-3278 b orbits too close to its star and is too hot for liquid water to exist on its surface.
How far away is TOI-3278 b?
TOI-3278 b is about 2,951 light-years from Earth in the constellation Pavo. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 51,935,840 years to get there.
How big is TOI-3278 b compared to Earth?
TOI-3278 b has 13.90 times the radius of Earth and about 95.3 times its mass.
How long is a year on TOI-3278 b?
One orbit around TOI-3278 takes 3.2 Earth days — short enough that 113 of its years would fit into one Earth year.
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