TOI-3664 b
TOI-3664 b is a hot Jupiter orbiting TOI-3664 in the constellation Cassiopeia. It lies about 1,516 light-years from Earth and was discovered in 2026 using the transit method.
How Big Is TOI-3664 b?
TOI-3664 b has a radius of 13.70 times that of Earth, or 1.22 times the radius of Jupiter. Its mass is 114 times that of Earth, giving it a density of 0.25 g/cm³ — closer to gas planets like Jupiter (1.33 g/cm³).
Is TOI-3664 b in the Habitable Zone?
TOI-3664 b orbits inside the inner edge of the habitable zone of TOI-3664. So close to its star, surface conditions are far too hot for liquid water.
Habitable zone of TOI-3664: 0.789–1.869 AU (conservative: 1.000–1.772 AU), per Kopparapu et al. (2014). Earth orbits the Sun at 1 AU.
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Temperature on TOI-3664 b
The equilibrium temperature of TOI-3664 b is about 1,232 K (959 °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-3664 b — one full orbit around TOI-3664 — lasts 3.30 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. Its orbit is mildly elliptical (eccentricity 0.16).
How Was TOI-3664 b Discovered?
TOI-3664 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-3664 b?
TOI-3664 b is 1,515.8 light-years (464.7 parsecs) from Earth. Light arriving here tonight left the planet about 1,516 years ago. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 26,678,080 years to make the journey.
The Host Star: TOI-3664
TOI-3664
- Surface temperature
- 5,593 K (Sun: 5,772 K)
- Mass
- 0.98 M☉
- Radius
- 1.11 R☉
- Age
- 9.0 billion years (Sun: 4.6)
Planetary System
TOI-3664 b is the only planet known to orbit TOI-3664 so far.
TOI-3664 b — Complete Data
| Radius | 13.697 Earth radii (1.222 Jupiter radii) |
|---|---|
| Mass | 114.42 Earth masses (0.360 Jupiter masses) |
| Density | 0.25 g/cm³ (Earth: 5.51) |
| Orbital period | 3.30 days |
| Orbital distance | 0.043 AU |
| Eccentricity | 0.159 |
| Equilibrium temperature | 1,232 K (959 °C) |
| Distance from Earth | 1,515.8 light-years (464.7 parsecs) |
| Constellation | Cassiopeia |
| Discovery method | Transit |
| Discovery facility | Transiting Exoplanet Survey Satellite (TESS) |
| Discovery year | 2026 |
Data: NASA Exoplanet Archive, last updated 2026-07-02. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About TOI-3664 b
Is TOI-3664 b habitable?
No — TOI-3664 b orbits too close to its star and is too hot for liquid water to exist on its surface.
How far away is TOI-3664 b?
TOI-3664 b is about 1,516 light-years from Earth in the constellation Cassiopeia. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 26,678,080 years to get there.
How big is TOI-3664 b compared to Earth?
TOI-3664 b has 13.70 times the radius of Earth and about 114 times its mass.
How long is a year on TOI-3664 b?
One orbit around TOI-3664 takes 3.3 Earth days — short enough that 111 of its years would fit into one Earth year.
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