TOI-1298 b
TOI-1298 b is a hot Jupiter orbiting TOI-1298 in the constellation Ursa Minor. It lies about 1,041 light-years from Earth and was discovered in 2021 using the transit method.
How Big Is TOI-1298 b?
TOI-1298 b has a radius of 9.66 times that of Earth, or 0.86 times the radius of Jupiter. Its mass is 99.0 times that of Earth, giving it a density of 0.60 g/cm³ — closer to gas planets like Jupiter (1.33 g/cm³).
Is TOI-1298 b in the Habitable Zone?
TOI-1298 b orbits inside the inner edge of the habitable zone of TOI-1298. So close to its star, surface conditions are far too hot for liquid water.
Habitable zone of TOI-1298: 1.087–2.563 AU (conservative: 1.377–2.430 AU), per Kopparapu et al. (2014). Earth orbits the Sun at 1 AU.
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Temperature on TOI-1298 b
The equilibrium temperature of TOI-1298 b is about 1,278 K (1,005 °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-1298 b — one full orbit around TOI-1298 — lasts 4.54 Earth days, shorter than Mercury's 88-day year. It orbits at an average distance of 0.057 AU — closer to its star than Mercury is to the Sun.
How Was TOI-1298 b Discovered?
TOI-1298 b was discovered in 2021 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-1298 b?
TOI-1298 b is 1,040.6 light-years (319.0 parsecs) from Earth. Light arriving here tonight left the planet about 1,041 years ago. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 18,314,560 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-1298 b scores 0.09, ranking #4,498 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: TOI-1298
TOI-1298
- Surface temperature
- 5,752 K (Sun: 5,772 K)
- Mass
- 1.22 M☉
- Radius
- 1.45 R☉
- Luminosity
- 2.0920 L☉
- Age
- 4.3 billion years (Sun: 4.6)
Planetary System
TOI-1298 b is the only planet known to orbit TOI-1298 so far.
TOI-1298 b — Complete Data
| Radius | 9.658 Earth radii (0.862 Jupiter radii) |
|---|---|
| Mass | 99.00 Earth masses (0.311 Jupiter masses) |
| Density | 0.60 g/cm³ (Earth: 5.51) |
| Orbital period | 4.54 days |
| Orbital distance | 0.057 AU |
| Equilibrium temperature | 1,278 K (1,005 °C) |
| Earth Similarity Index | 0.09 |
| Distance from Earth | 1,040.6 light-years (319.0 parsecs) |
| Constellation | Ursa Minor |
| Discovery method | Transit |
| Discovery facility | Transiting Exoplanet Survey Satellite (TESS) |
| Discovery year | 2021 |
Data: NASA Exoplanet Archive, last updated 2024-07-23. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About TOI-1298 b
Is TOI-1298 b habitable?
No — TOI-1298 b orbits too close to its star and is too hot for liquid water to exist on its surface.
How far away is TOI-1298 b?
TOI-1298 b is about 1,041 light-years from Earth in the constellation Ursa Minor. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 18,314,560 years to get there.
How big is TOI-1298 b compared to Earth?
TOI-1298 b has 9.66 times the radius of Earth and about 99.0 times its mass.
How long is a year on TOI-1298 b?
One orbit around TOI-1298 takes 4.5 Earth days — short enough that 81 of its years would fit into one Earth year.
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