HD 43691 b
HD 43691 b is a cold gas giant orbiting the G0 star HD 43691 in the constellation Auriga. It lies about 279 light-years from Earth and was discovered in 2007 using the radial velocity method.
Is HD 43691 b in the Habitable Zone?
HD 43691 b orbits inside the inner edge of the habitable zone of HD 43691. So close to its star, surface conditions are far too hot for liquid water.
Habitable zone of HD 43691: 1.309–3.061 AU (conservative: 1.658–2.902 AU), per Kopparapu et al. (2014). Earth orbits the Sun at 1 AU.
See the full interactive habitable-zone view in the Exoplanet Explorer app ›
Orbit and Year Length
A year on HD 43691 b — one full orbit around HD 43691 — lasts 37.0 Earth days, shorter than Mercury's 88-day year. It orbits at an average distance of 0.238 AU — closer to its star than Mercury is to the Sun. Its orbit is mildly elliptical (eccentricity 0.08).
How Was HD 43691 b Discovered?
HD 43691 b was discovered in 2007 using the radial velocity method, with observations from Haute-Provence 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 43691 b?
HD 43691 b is 279.2 light-years (85.6 parsecs) from Earth. Light arriving here tonight left the planet around the year 1747. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 4,913,920 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 43691 b scores 0.09, ranking #4,550 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: HD 43691
HD 43691 b belongs to a system of 3 stars; it orbits HD 43691.
HD 43691
- Spectral type
- G0
- Surface temperature
- 6,093 K (Sun: 5,772 K)
- Mass
- 1.32 M☉
- Radius
- 1.60 R☉
- Luminosity
- 3.1623 L☉
- Age
- 2.4 billion years (Sun: 4.6)
Planetary System
HD 43691 b is the only planet known to orbit HD 43691 so far.
HD 43691 b — Complete Data
| Mass (best estimate) | 810.47 Earth masses |
|---|---|
| Orbital period | 37.00 days |
| Orbital distance | 0.238 AU |
| Eccentricity | 0.080 |
| Earth Similarity Index | 0.09 |
| Distance from Earth | 279.2 light-years (85.6 parsecs) |
| Constellation | Auriga |
| Discovery method | Radial Velocity |
| Discovery facility | Haute-Provence Observatory |
| Discovery year | 2007 |
Data: NASA Exoplanet Archive, last updated 2018-09-25. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About HD 43691 b
Is HD 43691 b habitable?
No — HD 43691 b orbits too close to its star and is too hot for liquid water to exist on its surface.
How far away is HD 43691 b?
HD 43691 b is about 279 light-years from Earth in the constellation Auriga. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 4,913,920 years to get there.
How long is a year on HD 43691 b?
One orbit around HD 43691 takes 37.0 Earth days.
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