HD 129445 b
HD 129445 b is a cold gas giant orbiting the G6 V star HD 129445 in the constellation Circinus. It lies about 220 light-years from Earth and was discovered in 2009 using the radial velocity method.
Is HD 129445 b in the Habitable Zone?
The position of HD 129445 b relative to the habitable zone of HD 129445 cannot be precisely determined from the available orbital data.
Orbit and Year Length
A year on HD 129445 b — one full orbit around HD 129445 — lasts 1,840.0 Earth days, longer than an Earth year. It orbits at an average distance of 2.900 AU. Its orbit is highly elliptical (eccentricity 0.70), swinging dramatically closer to and farther from its star.
How Was HD 129445 b Discovered?
HD 129445 b was discovered in 2009 using the radial velocity method, with observations from Las Campanas 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 129445 b?
HD 129445 b is 220.0 light-years (67.4 parsecs) from Earth. Light arriving here tonight left the planet around the year 1806. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 3,872,000 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 129445 b scores 0.23, ranking #3,451 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: HD 129445
HD 129445
- Spectral type
- G6 V
- Mass
- 0.99 M☉
Planetary System
HD 129445 b is the only planet known to orbit HD 129445 so far.
HD 129445 b — Complete Data
| Mass (best estimate) | 508.51 Earth masses |
|---|---|
| Orbital period | 1,840.00 days |
| Orbital distance | 2.900 AU |
| Eccentricity | 0.700 |
| Earth Similarity Index | 0.23 |
| Distance from Earth | 220.0 light-years (67.4 parsecs) |
| Constellation | Circinus |
| Discovery method | Radial Velocity |
| Discovery facility | Las Campanas Observatory |
| Discovery year | 2009 |
Data: NASA Exoplanet Archive, last updated 2019-01-28. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About HD 129445 b
Is HD 129445 b habitable?
HD 129445 b is not known to orbit within the habitable zone of HD 129445, and as a cold gas giant it is an unlikely candidate for life as we know it.
How far away is HD 129445 b?
HD 129445 b is about 220 light-years from Earth in the constellation Circinus. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 3,872,000 years to get there.
How long is a year on HD 129445 b?
One orbit around HD 129445 takes 1,840.0 Earth days.
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