HR 8799 c
HR 8799 c is a cold gas giant orbiting the A5 V star HR 8799 in the constellation Pegasus. It lies about 135 light-years from Earth and was discovered in 2008 using the imaging method.
How Big Is HR 8799 c?
HR 8799 c has a radius of 13.00 times that of Earth, or 1.20 times the radius of Jupiter. Its mass is 3,000 times that of Earth.
Is HR 8799 c in the Habitable Zone?
The position of HR 8799 c relative to the habitable zone of HR 8799 cannot be precisely determined from the available orbital data.
Orbit and Year Length
A year on HR 8799 c — one full orbit around HR 8799 — lasts 69,000.0 Earth days, longer than Jupiter's 12-year orbit. It orbits at an average distance of 38.000 AU.
How Was HR 8799 c Discovered?
HR 8799 c was discovered in 2008 using the imaging method, with observations from Gemini Observatory.
Direct imaging captures actual pictures of a planet by blocking out the overwhelming glare of its host star. It works best for young, hot, massive planets on wide orbits.
How Far Away Is HR 8799 c?
HR 8799 c is 134.5 light-years (41.2 parsecs) from Earth. Light arriving here tonight left the planet around the year 1892. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 2,367,200 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. HR 8799 c scores 0.07, ranking #4,862 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: HR 8799
HR 8799
- Spectral type
- A5 V
- Mass
- 1.50 M☉
- Luminosity
- 4.9201 L☉
- Age
- 0.1 billion years (Sun: 4.6)
The HR 8799 Planetary System
HR 8799 c is one of 4 known planets in the HR 8799 system. Its siblings:
HR 8799 c — Complete Data
| Radius | 13.000 Earth radii (1.200 Jupiter radii) |
|---|---|
| Mass | 3,000.00 Earth masses (10.000 Jupiter masses) |
| Orbital period | 69,000.00 days |
| Orbital distance | 38.000 AU |
| Earth Similarity Index | 0.07 |
| Distance from Earth | 134.5 light-years (41.2 parsecs) |
| Constellation | Pegasus |
| Discovery method | Imaging |
| Discovery facility | Gemini Observatory |
| Discovery year | 2008 |
Data: NASA Exoplanet Archive, last updated 2014-05-14. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About HR 8799 c
Is HR 8799 c habitable?
HR 8799 c is not known to orbit within the habitable zone of HR 8799, and as a cold gas giant it is an unlikely candidate for life as we know it.
How far away is HR 8799 c?
HR 8799 c is about 135 light-years from Earth in the constellation Pegasus. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 2,367,200 years to get there.
How big is HR 8799 c compared to Earth?
HR 8799 c has 13.00 times the radius of Earth and about 3,000 times its mass.
How long is a year on HR 8799 c?
One orbit around HR 8799 takes 69,000.0 Earth days.
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