HD 106315 c
HD 106315 c is a Neptune-like planet orbiting the F5 V star HD 106315 in the constellation Virgo. It lies about 357 light-years from Earth and was discovered in 2017 using the transit method.
How Big Is HD 106315 c?
HD 106315 c has a radius of 4.35 times that of Earth. Its mass is 15.2 times that of Earth, giving it a density of 1.01 g/cm³ — closer to gas planets like Jupiter (1.33 g/cm³).
Is HD 106315 c in the Habitable Zone?
HD 106315 c orbits inside the inner edge of the habitable zone of HD 106315. So close to its star, surface conditions are far too hot for liquid water.
Habitable zone of HD 106315: 1.128–2.626 AU (conservative: 1.429–2.489 AU), per Kopparapu et al. (2014). Earth orbits the Sun at 1 AU.
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Temperature on HD 106315 c
The equilibrium temperature of HD 106315 c is about 886 K (613 °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 106315 c — one full orbit around HD 106315 — lasts 21.1 Earth days, shorter than Mercury's 88-day year. It orbits at an average distance of 0.154 AU — closer to its star than Mercury is to the Sun. Its orbit is mildly elliptical (eccentricity 0.22).
How Was HD 106315 c Discovered?
HD 106315 c was discovered in 2017 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 106315 c?
HD 106315 c is 356.7 light-years (109.4 parsecs) from Earth. Light arriving here tonight left the planet around the year 1670. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 6,277,920 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 106315 c scores 0.18, ranking #4,055 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: HD 106315
HD 106315
- Spectral type
- F5 V
- Surface temperature
- 6,327 K (Sun: 5,772 K)
- Mass
- 1.09 M☉
- Radius
- 1.30 R☉
- Age
- 4.5 billion years (Sun: 4.6)
The HD 106315 Planetary System
HD 106315 c is one of 2 known planets in the HD 106315 system. Its siblings:
- HD 106315 b (Super Earth)
HD 106315 c — Complete Data
| Radius | 4.350 Earth radii (0.388 Jupiter radii) |
|---|---|
| Mass | 15.20 Earth masses (0.048 Jupiter masses) |
| Density | 1.01 g/cm³ (Earth: 5.51) |
| Orbital period | 21.06 days |
| Orbital distance | 0.154 AU |
| Eccentricity | 0.220 |
| Equilibrium temperature | 886 K (613 °C) |
| Earth Similarity Index | 0.18 |
| Distance from Earth | 356.7 light-years (109.4 parsecs) |
| Constellation | Virgo |
| Discovery method | Transit |
| Discovery facility | K2 |
| Discovery year | 2017 |
Data: NASA Exoplanet Archive, last updated 2019-07-19. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About HD 106315 c
Is HD 106315 c habitable?
No — HD 106315 c orbits too close to its star and is too hot for liquid water to exist on its surface.
How far away is HD 106315 c?
HD 106315 c is about 357 light-years from Earth in the constellation Virgo. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 6,277,920 years to get there.
How big is HD 106315 c compared to Earth?
HD 106315 c has 4.35 times the radius of Earth and about 15.2 times its mass.
How long is a year on HD 106315 c?
One orbit around HD 106315 takes 21.1 Earth days — short enough that 17 of its years would fit into one Earth year.
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