TOI-824 b
TOI-824 b is a super-Earth orbiting the K4 V star TOI-824 in the constellation Circinus. It lies about 209 light-years from Earth and was discovered in 2020 using the transit method.
How Big Is TOI-824 b?
TOI-824 b has a radius of 2.93 times that of Earth. Its mass is 18.5 times that of Earth, giving it a density of 4.03 g/cm³ — between that of rocky and gaseous planets.
Is TOI-824 b in the Habitable Zone?
TOI-824 b orbits inside the inner edge of the habitable zone of TOI-824. So close to its star, surface conditions are far too hot for liquid water.
Habitable zone of TOI-824: 0.352–0.865 AU (conservative: 0.446–0.820 AU), per Kopparapu et al. (2014). Earth orbits the Sun at 1 AU.
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Temperature on TOI-824 b
The equilibrium temperature of TOI-824 b is about 1,253 K (980 °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. It receives 412 times the stellar energy that Earth gets from the Sun.
Orbit and Year Length
A year on TOI-824 b — one full orbit around TOI-824 — lasts just 33.4 hours, shorter than Mercury's 88-day year. It orbits at an average distance of 0.022 AU — closer to its star than Mercury is to the Sun.
How Was TOI-824 b Discovered?
TOI-824 b was discovered in 2020 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-824 b?
TOI-824 b is 208.5 light-years (63.9 parsecs) from Earth. Light arriving here tonight left the planet around the year 1818. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 3,669,600 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-824 b scores 0.22, ranking #3,711 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: TOI-824
TOI-824
- Spectral type
- K4 V
- Surface temperature
- 4,600 K (Sun: 5,772 K)
- Mass
- 0.71 M☉
- Radius
- 0.70 R☉
- Luminosity
- 0.1950 L☉
- Age
- 7.5 billion years (Sun: 4.6)
Planetary System
TOI-824 b is the only planet known to orbit TOI-824 so far.
TOI-824 b — Complete Data
| Radius | 2.926 Earth radii (0.261 Jupiter radii) |
|---|---|
| Mass | 18.47 Earth masses (0.058 Jupiter masses) |
| Density | 4.03 g/cm³ (Earth: 5.51) |
| Orbital period | 1.39 days |
| Orbital distance | 0.022 AU |
| Equilibrium temperature | 1,253 K (980 °C) |
| Stellar irradiation | 412.00× Earth |
| Earth Similarity Index | 0.22 |
| Distance from Earth | 208.5 light-years (63.9 parsecs) |
| Constellation | Circinus |
| Discovery method | Transit |
| Discovery facility | Transiting Exoplanet Survey Satellite (TESS) |
| Discovery year | 2020 |
Data: NASA Exoplanet Archive, last updated 2020-09-17. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About TOI-824 b
Is TOI-824 b habitable?
No — TOI-824 b orbits too close to its star and is too hot for liquid water to exist on its surface.
How far away is TOI-824 b?
TOI-824 b is about 209 light-years from Earth in the constellation Circinus. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 3,669,600 years to get there.
How big is TOI-824 b compared to Earth?
TOI-824 b has 2.93 times the radius of Earth and about 18.5 times its mass.
How long is a year on TOI-824 b?
One orbit around TOI-824 takes 1.4 Earth days — short enough that 262 of its years would fit into one Earth year.
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