TOI-1194 b
TOI-1194 b is a hot Jupiter orbiting TOI-1194 in the constellation Ursa Major. It lies about 488 light-years from Earth and was discovered in 2023 using the transit method.
How Big Is TOI-1194 b?
TOI-1194 b has a radius of 8.72 times that of Earth, or 0.78 times the radius of Jupiter. Its mass is 120 times that of Earth, giving it a density of 0.99 g/cm³ — closer to gas planets like Jupiter (1.33 g/cm³).
Is TOI-1194 b in the Habitable Zone?
TOI-1194 b orbits inside the inner edge of the habitable zone of TOI-1194. So close to its star, surface conditions are far too hot for liquid water.
Habitable zone of TOI-1194: 0.645–1.537 AU (conservative: 0.817–1.457 AU), per Kopparapu et al. (2014). Earth orbits the Sun at 1 AU.
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Temperature on TOI-1194 b
The equilibrium temperature of TOI-1194 b is about 1,264 K (991 °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-1194 b — one full orbit around TOI-1194 — lasts 2.31 Earth days, shorter than Mercury's 88-day year. It orbits at an average distance of 0.034 AU — closer to its star than Mercury is to the Sun.
How Was TOI-1194 b Discovered?
TOI-1194 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-1194 b?
TOI-1194 b is 488.1 light-years (149.7 parsecs) from Earth. Light arriving here tonight left the planet around the year 1538. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 8,590,560 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-1194 b scores 0.10, ranking #4,436 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: TOI-1194
TOI-1194
- Surface temperature
- 5,394 K (Sun: 5,772 K)
- Mass
- 0.98 M☉
- Radius
- 0.96 R☉
- Luminosity
- 0.7060 L☉
- Age
- 4.9 billion years (Sun: 4.6)
Planetary System
TOI-1194 b is the only planet known to orbit TOI-1194 so far.
TOI-1194 b — Complete Data
| Radius | 8.717 Earth radii (0.778 Jupiter radii) |
|---|---|
| Mass | 120.00 Earth masses (0.378 Jupiter masses) |
| Density | 0.99 g/cm³ (Earth: 5.51) |
| Orbital period | 2.31 days |
| Orbital distance | 0.034 AU |
| Equilibrium temperature | 1,264 K (991 °C) |
| Earth Similarity Index | 0.10 |
| Distance from Earth | 488.1 light-years (149.7 parsecs) |
| Constellation | Ursa Major |
| Discovery method | Transit |
| Discovery facility | Transiting Exoplanet Survey Satellite (TESS) |
| Discovery year | 2023 |
Data: NASA Exoplanet Archive, last updated 2024-07-22. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About TOI-1194 b
Is TOI-1194 b habitable?
No — TOI-1194 b orbits too close to its star and is too hot for liquid water to exist on its surface.
How far away is TOI-1194 b?
TOI-1194 b is about 488 light-years from Earth in the constellation Ursa Major. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 8,590,560 years to get there.
How big is TOI-1194 b compared to Earth?
TOI-1194 b has 8.72 times the radius of Earth and about 120 times its mass.
How long is a year on TOI-1194 b?
One orbit around TOI-1194 takes 2.3 Earth days — short enough that 158 of its years would fit into one Earth year.
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