HD 97658 b
HD 97658 b is a super-Earth orbiting the K1 V star HD 97658 in the constellation Leo. It lies about 70 light-years from Earth and was discovered in 2010 using the radial velocity method.
How Big Is HD 97658 b?
HD 97658 b has a radius of 2.12 times that of Earth. Its mass is 8.3 times that of Earth, giving it a density of 4.80 g/cm³ — comparable to rocky planets like Earth (5.51 g/cm³).
Is HD 97658 b in the Habitable Zone?
The position of HD 97658 b relative to the habitable zone of HD 97658 cannot be precisely determined from the available orbital data.
Habitable zone of HD 97658: 0.459–1.101 AU (conservative: 0.582–1.044 AU), per Kopparapu et al. (2014). Earth orbits the Sun at 1 AU.
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Temperature on HD 97658 b
The equilibrium temperature of HD 97658 b is about 751 K (478 °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 97658 b — one full orbit around HD 97658 — lasts 9.49 Earth days, shorter than Mercury's 88-day year. Its orbit is mildly elliptical (eccentricity 0.05).
How Was HD 97658 b Discovered?
HD 97658 b was discovered in 2010 using the radial velocity method, with observations from W. M. Keck Observatory.
The radial velocity method measures the subtle wobble of a star caused by the gravitational pull of an orbiting planet, visible as periodic shifts in the star's light spectrum. The size of the wobble reveals the planet's minimum mass.
How Far Away Is HD 97658 b?
HD 97658 b is 70.3 light-years (21.6 parsecs) from Earth. Light arriving here tonight left the planet around the year 1956. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 1,237,280 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 97658 b scores 0.27, ranking #2,514 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: HD 97658
HD 97658
- Spectral type
- K1 V
- Surface temperature
- 5,212 K (Sun: 5,772 K)
- Mass
- 0.85 M☉
- Radius
- 0.73 R☉
- Luminosity
- 0.3510 L☉
- Age
- 3.9 billion years (Sun: 4.6)
Planetary System
HD 97658 b is the only planet known to orbit HD 97658 so far.
HD 97658 b — Complete Data
| Radius | 2.120 Earth radii (0.189 Jupiter radii) |
|---|---|
| Mass | 8.30 Earth masses (0.026 Jupiter masses) |
| Density | 4.80 g/cm³ (Earth: 5.51) |
| Orbital period | 9.49 days |
| Eccentricity | 0.050 |
| Equilibrium temperature | 751 K (478 °C) |
| Earth Similarity Index | 0.27 |
| Distance from Earth | 70.3 light-years (21.6 parsecs) |
| Constellation | Leo |
| Discovery method | Radial Velocity |
| Discovery facility | W. M. Keck Observatory |
| Discovery year | 2010 |
Data: NASA Exoplanet Archive, last updated 2023-03-28. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About HD 97658 b
Is HD 97658 b habitable?
HD 97658 b is not known to orbit within the habitable zone of HD 97658, and as a super-Earth it is an unlikely candidate for life as we know it.
How far away is HD 97658 b?
HD 97658 b is about 70 light-years from Earth in the constellation Leo. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 1,237,280 years to get there.
How big is HD 97658 b compared to Earth?
HD 97658 b has 2.12 times the radius of Earth and about 8.3 times its mass.
How long is a year on HD 97658 b?
One orbit around HD 97658 takes 9.5 Earth days — short enough that 38 of its years would fit into one Earth year.
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