HD 39194 b
HD 39194 b is a super-Earth orbiting HD 39194 in the constellation Mensa. It lies about 86 light-years from Earth and was discovered in 2021 using the radial velocity method.
Is HD 39194 b in the Habitable Zone?
The position of HD 39194 b relative to the habitable zone of HD 39194 cannot be precisely determined from the available orbital data.
Orbit and Year Length
A year on HD 39194 b — one full orbit around HD 39194 — lasts 5.64 Earth days, shorter than Mercury's 88-day year. It orbits at an average distance of 0.059 AU — closer to its star than Mercury is to the Sun. Its orbit is mildly elliptical (eccentricity 0.10).
How Was HD 39194 b Discovered?
HD 39194 b was discovered in 2021 using the radial velocity method, with observations from La Silla 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 39194 b?
HD 39194 b is 86.1 light-years (26.4 parsecs) from Earth. Light arriving here tonight left the planet around the year 1940. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 1,515,360 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 39194 b scores 0.27, ranking #2,470 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: HD 39194
HD 39194
- Mass
- 0.86 M☉
The HD 39194 Planetary System
HD 39194 b is one of 3 known planets in the HD 39194 system. Its siblings:
- HD 39194 c (Super Earth)
- HD 39194 d (Super Earth)
HD 39194 b — Complete Data
| Mass (best estimate) | 4.62 Earth masses |
|---|---|
| Orbital period | 5.64 days |
| Orbital distance | 0.059 AU |
| Eccentricity | 0.101 |
| Earth Similarity Index | 0.27 |
| Distance from Earth | 86.1 light-years (26.4 parsecs) |
| Constellation | Mensa |
| Discovery method | Radial Velocity |
| Discovery facility | La Silla Observatory |
| Discovery year | 2021 |
Data: NASA Exoplanet Archive, last updated 2026-03-05. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About HD 39194 b
Is HD 39194 b habitable?
HD 39194 b is not known to orbit within the habitable zone of HD 39194, and as a super-Earth it is an unlikely candidate for life as we know it.
How far away is HD 39194 b?
HD 39194 b is about 86 light-years from Earth in the constellation Mensa. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 1,515,360 years to get there.
How long is a year on HD 39194 b?
One orbit around HD 39194 takes 5.6 Earth days — short enough that 65 of its years would fit into one Earth year.
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