Qatar-3 b
Qatar-3 b is a hot Jupiter orbiting the G0 V star Qatar-3 in the constellation Andromeda. It lies about 2,399 light-years from Earth and was discovered in 2017 using the transit method.
How Big Is Qatar-3 b?
Qatar-3 b has a radius of 12.29 times that of Earth, or 1.10 times the radius of Jupiter. Its mass is 1,370 times that of Earth, giving it a density of 4.00 g/cm³ — between that of rocky and gaseous planets.
Is Qatar-3 b in the Habitable Zone?
Qatar-3 b orbits inside the inner edge of the habitable zone of Qatar-3. So close to its star, surface conditions are far too hot for liquid water.
Habitable zone of Qatar-3: 1.020–2.390 AU (conservative: 1.292–2.266 AU), per Kopparapu et al. (2014). Earth orbits the Sun at 1 AU.
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Temperature on Qatar-3 b
The equilibrium temperature of Qatar-3 b is about 1,681 K (1,408 °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. It receives 1,330 times the stellar energy that Earth gets from the Sun.
Orbit and Year Length
A year on Qatar-3 b — one full orbit around Qatar-3 — lasts 2.51 Earth days, shorter than Mercury's 88-day year. It orbits at an average distance of 0.038 AU — closer to its star than Mercury is to the Sun.
How Was Qatar-3 b Discovered?
Qatar-3 b was discovered in 2017 using the transit method, with observations from Qatar.
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 Qatar-3 b?
Qatar-3 b is 2,399.2 light-years (735.6 parsecs) from Earth. Light arriving here tonight left the planet about 2,399 years ago. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 42,225,920 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. Qatar-3 b scores 0.07, ranking #4,856 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: Qatar-3
Qatar-3
- Spectral type
- G0 V
- Surface temperature
- 6,007 K (Sun: 5,772 K)
- Mass
- 1.15 M☉
- Radius
- 1.27 R☉
- Luminosity
- 1.9000 L☉
- Age
- 0.3 billion years (Sun: 4.6)
Planetary System
Qatar-3 b is the only planet known to orbit Qatar-3 so far.
Qatar-3 b — Complete Data
| Radius | 12.285 Earth radii (1.096 Jupiter radii) |
|---|---|
| Mass | 1,369.85 Earth masses (4.310 Jupiter masses) |
| Density | 4.00 g/cm³ (Earth: 5.51) |
| Orbital period | 2.51 days |
| Orbital distance | 0.038 AU |
| Equilibrium temperature | 1,681 K (1,408 °C) |
| Stellar irradiation | 1,330.00× Earth |
| Earth Similarity Index | 0.07 |
| Distance from Earth | 2,399.2 light-years (735.6 parsecs) |
| Constellation | Andromeda |
| Discovery method | Transit |
| Discovery facility | Qatar |
| Discovery year | 2017 |
Data: NASA Exoplanet Archive, last updated 2017-04-24. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About Qatar-3 b
Is Qatar-3 b habitable?
No — Qatar-3 b orbits too close to its star and is too hot for liquid water to exist on its surface.
How far away is Qatar-3 b?
Qatar-3 b is about 2,399 light-years from Earth in the constellation Andromeda. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 42,225,920 years to get there.
How big is Qatar-3 b compared to Earth?
Qatar-3 b has 12.29 times the radius of Earth and about 1,370 times its mass.
How long is a year on Qatar-3 b?
One orbit around Qatar-3 takes 2.5 Earth days — short enough that 146 of its years would fit into one Earth year.
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