TOI-1173 b
TOI-1173 b is a hot Jupiter orbiting TOI-1173 in the constellation Ursa Minor. It lies about 432 light-years from Earth and was discovered in 2024 using the transit method.
How Big Is TOI-1173 b?
TOI-1173 b has a radius of 8.78 times that of Earth, or 0.78 times the radius of Jupiter. Its mass is 28.3 times that of Earth, giving it a density of 0.23 g/cm³ — closer to gas planets like Jupiter (1.33 g/cm³).
Is TOI-1173 b in the Habitable Zone?
The position of TOI-1173 b relative to the habitable zone of TOI-1173 cannot be precisely determined from the available orbital data.
Orbit and Year Length
A year on TOI-1173 b — one full orbit around TOI-1173 — lasts 7.06 Earth days, shorter than Mercury's 88-day year. Its orbit is nearly circular (eccentricity 0.037).
How Was TOI-1173 b Discovered?
TOI-1173 b was discovered in 2024 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-1173 b?
TOI-1173 b is 431.7 light-years (132.4 parsecs) from Earth. Light arriving here tonight left the planet around the year 1595. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 7,597,920 years to make the journey.
The Host Star: TOI-1173
TOI-1173 b belongs to a system of 2 stars; it orbits TOI-1173.
TOI-1173
Planetary System
TOI-1173 b is the only planet known to orbit TOI-1173 so far.
TOI-1173 b — Complete Data
| Radius | 8.777 Earth radii (0.783 Jupiter radii) |
|---|---|
| Mass | 28.29 Earth masses (0.089 Jupiter masses) |
| Density | 0.23 g/cm³ (Earth: 5.51) |
| Orbital period | 7.06 days |
| Eccentricity | 0.037 |
| Distance from Earth | 431.7 light-years (132.4 parsecs) |
| Constellation | Ursa Minor |
| Discovery method | Transit |
| Discovery facility | Transiting Exoplanet Survey Satellite (TESS) |
| Discovery year | 2024 |
Data: NASA Exoplanet Archive, last updated 2026-09-03. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About TOI-1173 b
Is TOI-1173 b habitable?
TOI-1173 b is not known to orbit within the habitable zone of TOI-1173, and as a hot Jupiter it is an unlikely candidate for life as we know it.
How far away is TOI-1173 b?
TOI-1173 b is about 432 light-years from Earth in the constellation Ursa Minor. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 7,597,920 years to get there.
How big is TOI-1173 b compared to Earth?
TOI-1173 b has 8.78 times the radius of Earth and about 28.3 times its mass.
How long is a year on TOI-1173 b?
One orbit around TOI-1173 takes 7.1 Earth days — short enough that 52 of its years would fit into one Earth year.
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