HD 45184 b
HD 45184 b is a Neptune-like planet orbiting the G1.5 V star HD 45184 in the constellation Canis Major. It lies about 72 light-years from Earth and was discovered in 2019 using the radial velocity method.
Is HD 45184 b in the Habitable Zone?
HD 45184 b orbits inside the inner edge of the habitable zone of HD 45184. So close to its star, surface conditions are far too hot for liquid water.
Habitable zone of HD 45184: 0.793–1.865 AU (conservative: 1.005–1.768 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 45184 b — one full orbit around HD 45184 — lasts 5.89 Earth days, shorter than Mercury's 88-day year. It orbits at an average distance of 0.064 AU — closer to its star than Mercury is to the Sun. Its orbit is mildly elliptical (eccentricity 0.07).
How Was HD 45184 b Discovered?
HD 45184 b was discovered in 2019 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 45184 b?
HD 45184 b is 71.6 light-years (22.0 parsecs) from Earth. Light arriving here tonight left the planet around the year 1955. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 1,260,160 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 45184 b scores 0.19, ranking #3,929 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: HD 45184
HD 45184
- Spectral type
- G1.5 V
- Surface temperature
- 5,869 K (Sun: 5,772 K)
- Mass
- 1.03 M☉
- Luminosity
- 1.1300 L☉
The HD 45184 Planetary System
HD 45184 b is one of 2 known planets in the HD 45184 system. Its siblings:
- HD 45184 c (Super Earth)
HD 45184 b — Complete Data
| Mass (best estimate) | 12.19 Earth masses |
|---|---|
| Orbital period | 5.89 days |
| Orbital distance | 0.064 AU |
| Eccentricity | 0.070 |
| Earth Similarity Index | 0.19 |
| Distance from Earth | 71.6 light-years (22.0 parsecs) |
| Constellation | Canis Major |
| Discovery method | Radial Velocity |
| Discovery facility | La Silla Observatory |
| Discovery year | 2019 |
Data: NASA Exoplanet Archive, last updated 2019-02-05. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About HD 45184 b
Is HD 45184 b habitable?
No — HD 45184 b orbits too close to its star and is too hot for liquid water to exist on its surface.
How far away is HD 45184 b?
HD 45184 b is about 72 light-years from Earth in the constellation Canis Major. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 1,260,160 years to get there.
How long is a year on HD 45184 b?
One orbit around HD 45184 takes 5.9 Earth days — short enough that 62 of its years would fit into one Earth year.
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