HD 80653 b
HD 80653 b is a lava world orbiting HD 80653 in the constellation Cancer. It lies about 358 light-years from Earth and was discovered in 2020 using the transit method.
How Big Is HD 80653 b?
HD 80653 b has a radius of 1.61 times that of Earth. Its mass is 5.7 times that of Earth, giving it a density of 7.47 g/cm³ — comparable to rocky planets like Earth (5.51 g/cm³).
Is HD 80653 b in the Habitable Zone?
HD 80653 b orbits inside the inner edge of the habitable zone of HD 80653. So close to its star, surface conditions are far too hot for liquid water.
Habitable zone of HD 80653: 0.963–2.259 AU (conservative: 1.220–2.142 AU), per Kopparapu et al. (2014). Earth orbits the Sun at 1 AU.
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Temperature on HD 80653 b
The equilibrium temperature of HD 80653 b is about 2,463 K (2,190 °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 6,130 times the stellar energy that Earth gets from the Sun.
Orbit and Year Length
A year on HD 80653 b — one full orbit around HD 80653 — lasts just 17.3 hours, shorter than Mercury's 88-day year. It orbits at an average distance of 0.017 AU — closer to its star than Mercury is to the Sun.
How Was HD 80653 b Discovered?
HD 80653 b was discovered in 2020 using the transit method, with observations from K2.
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 HD 80653 b?
HD 80653 b is 358.3 light-years (109.9 parsecs) from Earth. Light arriving here tonight left the planet around the year 1668. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 6,306,080 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. HD 80653 b scores 0.27, ranking #2,464 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: HD 80653
HD 80653
- Surface temperature
- 5,959 K (Sun: 5,772 K)
- Mass
- 1.18 M☉
- Radius
- 1.22 R☉
- Age
- 2.7 billion years (Sun: 4.6)
The HD 80653 Planetary System
HD 80653 b is one of 2 known planets in the HD 80653 system. Its siblings:
- K2-312 c (Cold Gas Giant)
HD 80653 b — Complete Data
| Radius | 1.613 Earth radii (0.144 Jupiter radii) |
|---|---|
| Mass | 5.72 Earth masses (0.018 Jupiter masses) |
| Density | 7.47 g/cm³ (Earth: 5.51) |
| Orbital period | 0.72 days |
| Orbital distance | 0.017 AU |
| Equilibrium temperature | 2,463 K (2,190 °C) |
| Stellar irradiation | 6,130.00× Earth |
| Earth Similarity Index | 0.27 |
| Distance from Earth | 358.3 light-years (109.9 parsecs) |
| Constellation | Cancer |
| Discovery method | Transit |
| Discovery facility | K2 |
| Discovery year | 2020 |
Data: NASA Exoplanet Archive, last updated 2023-04-17. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About HD 80653 b
Is HD 80653 b habitable?
No — HD 80653 b orbits too close to its star and is too hot for liquid water to exist on its surface.
How far away is HD 80653 b?
HD 80653 b is about 358 light-years from Earth in the constellation Cancer. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 6,306,080 years to get there.
How big is HD 80653 b compared to Earth?
HD 80653 b has 1.61 times the radius of Earth and about 5.7 times its mass.
How long is a year on HD 80653 b?
One orbit around HD 80653 takes 0.7 Earth days — short enough that 508 of its years would fit into one Earth year.
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