HATS-7 b
HATS-7 b is a hot Jupiter orbiting the K2 star HATS-7 in the constellation Virgo. It lies about 785 light-years from Earth and was discovered in 2015 using the transit method.
How Big Is HATS-7 b?
HATS-7 b has a radius of 6.31 times that of Earth, or 0.56 times the radius of Jupiter. Its mass is 38.1 times that of Earth, giving it a density of 0.83 g/cm³ — closer to gas planets like Jupiter (1.33 g/cm³).
Is HATS-7 b in the Habitable Zone?
HATS-7 b orbits inside the inner edge of the habitable zone of HATS-7. So close to its star, surface conditions are far too hot for liquid water.
Habitable zone of HATS-7: 0.475–1.150 AU (conservative: 0.602–1.091 AU), per Kopparapu et al. (2014). Earth orbits the Sun at 1 AU.
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Temperature on HATS-7 b
The equilibrium temperature of HATS-7 b is about 1,084 K (811 °C) — hot enough to melt many metals. This estimate ignores any atmosphere, which could change surface temperatures dramatically — Earth's greenhouse effect adds about 33 °C.
Orbit and Year Length
A year on HATS-7 b — one full orbit around HATS-7 — lasts 3.19 Earth days, shorter than Mercury's 88-day year. It orbits at an average distance of 0.040 AU — closer to its star than Mercury is to the Sun. Its orbit is mildly elliptical (eccentricity 0.17).
How Was HATS-7 b Discovered?
HATS-7 b was discovered in 2015 using the transit method, with observations from HATSouth.
The transit method watches a star for the tiny, regular dip in brightness that occurs when a planet crosses in front of it. The depth and timing of these dips reveal the planet's size and orbital period.
How Far Away Is HATS-7 b?
HATS-7 b is 785.1 light-years (240.7 parsecs) from Earth. Light arriving here tonight left the planet around the year 1241. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 13,817,760 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. HATS-7 b scores 0.13, ranking #4,284 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: HATS-7
HATS-7
- Spectral type
- K2
- Surface temperature
- 4,985 K (Sun: 5,772 K)
- Mass
- 0.85 M☉
- Radius
- 0.82 R☉
- Luminosity
- 0.3680 L☉
- Age
- 7.8 billion years (Sun: 4.6)
Planetary System
HATS-7 b is the only planet known to orbit HATS-7 so far.
HATS-7 b — Complete Data
| Radius | 6.311 Earth radii (0.563 Jupiter radii) |
|---|---|
| Mass | 38.14 Earth masses (0.120 Jupiter masses) |
| Density | 0.83 g/cm³ (Earth: 5.51) |
| Orbital period | 3.19 days |
| Orbital distance | 0.040 AU |
| Eccentricity | 0.170 |
| Equilibrium temperature | 1,084 K (811 °C) |
| Earth Similarity Index | 0.13 |
| Distance from Earth | 785.1 light-years (240.7 parsecs) |
| Constellation | Virgo |
| Discovery method | Transit |
| Discovery facility | HATSouth |
| Discovery year | 2015 |
Data: NASA Exoplanet Archive, last updated 2018-05-22. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About HATS-7 b
Is HATS-7 b habitable?
No — HATS-7 b orbits too close to its star and is too hot for liquid water to exist on its surface.
How far away is HATS-7 b?
HATS-7 b is about 785 light-years from Earth in the constellation Virgo. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 13,817,760 years to get there.
How big is HATS-7 b compared to Earth?
HATS-7 b has 6.31 times the radius of Earth and about 38.1 times its mass.
How long is a year on HATS-7 b?
One orbit around HATS-7 takes 3.2 Earth days — short enough that 115 of its years would fit into one Earth year.
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