HAT-P-2 c
HAT-P-2 c is a cold gas giant orbiting the F8 star HAT-P-2 in the constellation Hercules. It lies about 417 light-years from Earth and was discovered in 2023 using the radial velocity method.
Is HAT-P-2 c in the Habitable Zone?
The position of HAT-P-2 c relative to the habitable zone of HAT-P-2 cannot be precisely determined from the available orbital data.
Habitable zone of HAT-P-2: 1.332–3.098 AU (conservative: 1.687–2.937 AU), per Kopparapu et al. (2014). Earth orbits the Sun at 1 AU.
See the full interactive habitable-zone view in the Exoplanet Explorer app ›
Orbit and Year Length
A year on HAT-P-2 c — one full orbit around HAT-P-2 — lasts 8,500.0 Earth days, longer than Jupiter's 12-year orbit. Its orbit is highly elliptical (eccentricity 0.37), swinging dramatically closer to and farther from its star.
How Was HAT-P-2 c Discovered?
HAT-P-2 c was discovered in 2023 using the radial velocity method, with observations from Multiple Observatories.
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 HAT-P-2 c?
HAT-P-2 c is 416.7 light-years (127.8 parsecs) from Earth. Light arriving here tonight left the planet around the year 1610. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 7,333,920 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. HAT-P-2 c scores 0.13, ranking #4,288 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: HAT-P-2
HAT-P-2
- Spectral type
- F8
- Surface temperature
- 6,380 K (Sun: 5,772 K)
- Mass
- 1.33 M☉
- Radius
- 1.39 R☉
- Luminosity
- 3.3884 L☉
- Age
- 1.4 billion years (Sun: 4.6)
The HAT-P-2 Planetary System
HAT-P-2 c is one of 2 known planets in the HAT-P-2 system. Its siblings:
- HAT-P-2 b (Hot Jupiter)
HAT-P-2 c — Complete Data
| Mass | 3,400.76 Earth masses (10.700 Jupiter masses) |
|---|---|
| Orbital period | 8,500.00 days |
| Eccentricity | 0.370 |
| Earth Similarity Index | 0.13 |
| Distance from Earth | 416.7 light-years (127.8 parsecs) |
| Constellation | Hercules |
| Discovery method | Radial Velocity |
| Discovery facility | Multiple Observatories |
| Discovery year | 2023 |
Data: NASA Exoplanet Archive, last updated 2023-10-09. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About HAT-P-2 c
Is HAT-P-2 c habitable?
HAT-P-2 c is not known to orbit within the habitable zone of HAT-P-2, and as a cold gas giant it is an unlikely candidate for life as we know it.
How far away is HAT-P-2 c?
HAT-P-2 c is about 417 light-years from Earth in the constellation Hercules. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 7,333,920 years to get there.
How long is a year on HAT-P-2 c?
One orbit around HAT-P-2 takes 8,500.0 Earth days.
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