HD 75784 b
HD 75784 b is a cold gas giant orbiting HD 75784 in the constellation Cancer. It lies about 279 light-years from Earth and was discovered in 2014 using the radial velocity method.
Is HD 75784 b in the Habitable Zone?
HD 75784 b orbits inside the inner edge of the habitable zone of HD 75784. So close to its star, surface conditions are far too hot for liquid water.
Habitable zone of HD 75784: 1.901–4.622 AU (conservative: 2.408–4.382 AU), per Kopparapu et al. (2014). Earth orbits the Sun at 1 AU.
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Orbit and Year Length
A year on HD 75784 b — one full orbit around HD 75784 — lasts 341.2 Earth days, between the years of Mercury (88 days) and Earth (365 days). It orbits at an average distance of 1.032 AU — comparable to the inner Solar System. Its orbit is mildly elliptical (eccentricity 0.10).
How Was HD 75784 b Discovered?
HD 75784 b was discovered in 2014 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 75784 b?
HD 75784 b is 278.6 light-years (85.4 parsecs) from Earth. Light arriving here tonight left the planet around the year 1748. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 4,903,360 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 75784 b scores 0.22, ranking #3,661 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: HD 75784
HD 75784
- Surface temperature
- 4,867 K (Sun: 5,772 K)
- Mass
- 1.26 M☉
- Radius
- 3.40 R☉
The HD 75784 Planetary System
HD 75784 b is one of 2 known planets in the HD 75784 system. Its siblings:
- HD 75784 c (Cold Gas Giant)
HD 75784 b — Complete Data
| Mass (best estimate) | 317.83 Earth masses |
|---|---|
| Orbital period | 341.20 days |
| Orbital distance | 1.032 AU |
| Eccentricity | 0.097 |
| Earth Similarity Index | 0.22 |
| Distance from Earth | 278.6 light-years (85.4 parsecs) |
| Constellation | Cancer |
| Discovery method | Radial Velocity |
| Discovery facility | W. M. Keck Observatory |
| Discovery year | 2014 |
Data: NASA Exoplanet Archive, last updated 2018-12-03. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About HD 75784 b
Is HD 75784 b habitable?
No — HD 75784 b orbits too close to its star and is too hot for liquid water to exist on its surface.
How far away is HD 75784 b?
HD 75784 b is about 279 light-years from Earth in the constellation Cancer. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 4,903,360 years to get there.
How long is a year on HD 75784 b?
One orbit around HD 75784 takes 341.2 Earth days.
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