HD 89345 b
HD 89345 b is a hot Jupiter orbiting HD 89345 in the constellation Leo. It lies about 432 light-years from Earth and was discovered in 2018 using the transit method.
How Big Is HD 89345 b?
HD 89345 b has a radius of 7.40 times that of Earth, or 0.66 times the radius of Jupiter. Its mass is 35.0 times that of Earth, giving it a density of 0.47 g/cm³ — closer to gas planets like Jupiter (1.33 g/cm³).
Is HD 89345 b in the Habitable Zone?
HD 89345 b orbits inside the inner edge of the habitable zone of HD 89345. So close to its star, surface conditions are far too hot for liquid water.
Habitable zone of HD 89345: 1.239–2.935 AU (conservative: 1.569–2.783 AU), per Kopparapu et al. (2014). Earth orbits the Sun at 1 AU.
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Temperature on HD 89345 b
The equilibrium temperature of HD 89345 b is about 1,089 K (816 °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 HD 89345 b — one full orbit around HD 89345 — lasts 11.8 Earth days, shorter than Mercury's 88-day year. It orbits at an average distance of 0.107 AU — closer to its star than Mercury is to the Sun. Its orbit is mildly elliptical (eccentricity 0.22).
How Was HD 89345 b Discovered?
HD 89345 b was discovered in 2018 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 89345 b?
HD 89345 b is 431.7 light-years (132.3 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.
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 89345 b scores 0.12, ranking #4,346 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: HD 89345
HD 89345
- Surface temperature
- 5,576 K (Sun: 5,772 K)
- Mass
- 1.16 M☉
- Radius
- 1.75 R☉
- Luminosity
- 2.6600 L☉
- Age
- 7.5 billion years (Sun: 4.6)
Planetary System
HD 89345 b is the only planet known to orbit HD 89345 so far.
HD 89345 b — Complete Data
| Radius | 7.398 Earth radii (0.660 Jupiter radii) |
|---|---|
| Mass | 34.96 Earth masses (0.110 Jupiter masses) |
| Density | 0.47 g/cm³ (Earth: 5.51) |
| Orbital period | 11.81 days |
| Orbital distance | 0.107 AU |
| Eccentricity | 0.220 |
| Equilibrium temperature | 1,089 K (816 °C) |
| Earth Similarity Index | 0.12 |
| Distance from Earth | 431.7 light-years (132.3 parsecs) |
| Constellation | Leo |
| Discovery method | Transit |
| Discovery facility | K2 |
| Discovery year | 2018 |
Data: NASA Exoplanet Archive, last updated 2018-08-21. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About HD 89345 b
Is HD 89345 b habitable?
No — HD 89345 b orbits too close to its star and is too hot for liquid water to exist on its surface.
How far away is HD 89345 b?
HD 89345 b is about 432 light-years from Earth in the constellation Leo. 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 HD 89345 b compared to Earth?
HD 89345 b has 7.40 times the radius of Earth and about 35.0 times its mass.
How long is a year on HD 89345 b?
One orbit around HD 89345 takes 11.8 Earth days — short enough that 31 of its years would fit into one Earth year.
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