TOI-784 b
TOI-784 b is a super-Earth orbiting the G star HD 307842 in the constellation Carina. It lies about 211 light-years from Earth and was discovered in 2023 using the transit method.
How Big Is TOI-784 b?
TOI-784 b has a radius of 1.93 times that of Earth. Its mass is 9.7 times that of Earth, giving it a density of 7.40 g/cm³ — comparable to rocky planets like Earth (5.51 g/cm³).
Is TOI-784 b in the Habitable Zone?
TOI-784 b orbits inside the inner edge of the habitable zone of HD 307842. So close to its star, surface conditions are far too hot for liquid water.
Habitable zone of HD 307842: 0.638–1.513 AU (conservative: 0.808–1.434 AU), per Kopparapu et al. (2014). Earth orbits the Sun at 1 AU.
See the full interactive habitable-zone view in the Exoplanet Explorer app ›
Orbit and Year Length
A year on TOI-784 b — one full orbit around HD 307842 — lasts 2.80 Earth days, shorter than Mercury's 88-day year. It orbits at an average distance of 0.038 AU — closer to its star than Mercury is to the Sun.
How Was TOI-784 b Discovered?
TOI-784 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-784 b?
TOI-784 b is 210.7 light-years (64.6 parsecs) from Earth. Light arriving here tonight left the planet around the year 1816. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 3,708,320 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-784 b scores 0.26, ranking #2,840 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: HD 307842
HD 307842
- Spectral type
- G
- Surface temperature
- 5,558 K (Sun: 5,772 K)
- Mass
- 0.91 M☉
- Radius
- 0.91 R☉
Planetary System
TOI-784 b is the only planet known to orbit HD 307842 so far.
TOI-784 b — Complete Data
| Radius | 1.930 Earth radii (0.172 Jupiter radii) |
|---|---|
| Mass | 9.67 Earth masses (0.030 Jupiter masses) |
| Density | 7.40 g/cm³ (Earth: 5.51) |
| Orbital period | 2.80 days |
| Orbital distance | 0.038 AU |
| Earth Similarity Index | 0.26 |
| Distance from Earth | 210.7 light-years (64.6 parsecs) |
| Constellation | Carina |
| Discovery method | Transit |
| Discovery facility | Transiting Exoplanet Survey Satellite (TESS) |
| Discovery year | 2023 |
Data: NASA Exoplanet Archive, last updated 2023-07-10. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About TOI-784 b
Is TOI-784 b habitable?
No — TOI-784 b orbits too close to its star and is too hot for liquid water to exist on its surface.
How far away is TOI-784 b?
TOI-784 b is about 211 light-years from Earth in the constellation Carina. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 3,708,320 years to get there.
How big is TOI-784 b compared to Earth?
TOI-784 b has 1.93 times the radius of Earth and about 9.7 times its mass.
How long is a year on TOI-784 b?
One orbit around HD 307842 takes 2.8 Earth days — short enough that 131 of its years would fit into one Earth year.
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