HD 63935 b
HD 63935 b is a mini-Neptune orbiting HD 63935 in the constellation Canis Minor. It lies about 160 light-years from Earth and was discovered in 2021 using the transit method.
How Big Is HD 63935 b?
HD 63935 b has a radius of 2.92 times that of Earth. Its mass is 10.5 times that of Earth, giving it a density of 2.32 g/cm³ — between that of rocky and gaseous planets.
Is HD 63935 b in the Habitable Zone?
HD 63935 b orbits inside the inner edge of the habitable zone of HD 63935. So close to its star, surface conditions are far too hot for liquid water.
Habitable zone of HD 63935: 0.668–1.586 AU (conservative: 0.846–1.504 AU), per Kopparapu et al. (2014). Earth orbits the Sun at 1 AU.
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Temperature on HD 63935 b
The equilibrium temperature of HD 63935 b is about 825 K (552 °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 63935 b — one full orbit around HD 63935 — lasts 9.06 Earth days, shorter than Mercury's 88-day year. It orbits at an average distance of 0.083 AU — closer to its star than Mercury is to the Sun.
How Was HD 63935 b Discovered?
HD 63935 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 HD 63935 b?
HD 63935 b is 159.7 light-years (49.0 parsecs) from Earth. Light arriving here tonight left the planet around the year 1867. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 2,810,720 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 63935 b scores 0.22, ranking #3,639 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: HD 63935
HD 63935
- Surface temperature
- 5,513 K (Sun: 5,772 K)
- Mass
- 0.94 M☉
- Radius
- 0.96 R☉
- Luminosity
- 0.7680 L☉
- Age
- 6.6 billion years (Sun: 4.6)
The HD 63935 Planetary System
HD 63935 b is one of 2 known planets in the HD 63935 system. Its siblings:
- HD 63935 c (Sub Neptune)
HD 63935 b — Complete Data
| Radius | 2.916 Earth radii (0.260 Jupiter radii) |
|---|---|
| Mass | 10.50 Earth masses (0.033 Jupiter masses) |
| Density | 2.32 g/cm³ (Earth: 5.51) |
| Orbital period | 9.06 days |
| Orbital distance | 0.083 AU |
| Equilibrium temperature | 825 K (552 °C) |
| Earth Similarity Index | 0.22 |
| Distance from Earth | 159.7 light-years (49.0 parsecs) |
| Constellation | Canis 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 HD 63935 b
Is HD 63935 b habitable?
No — HD 63935 b orbits too close to its star and is too hot for liquid water to exist on its surface.
How far away is HD 63935 b?
HD 63935 b is about 160 light-years from Earth in the constellation Canis Minor. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 2,810,720 years to get there.
How big is HD 63935 b compared to Earth?
HD 63935 b has 2.92 times the radius of Earth and about 10.5 times its mass.
How long is a year on HD 63935 b?
One orbit around HD 63935 takes 9.1 Earth days — short enough that 40 of its years would fit into one Earth year.
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