HD 148797 b
HD 148797 b is a cold gas giant orbiting the F6 star HD 148797 in the constellation Norma. It lies about 562 light-years from Earth and was discovered in 2026 using the transit method.
How Big Is HD 148797 b?
HD 148797 b has a radius of 8.25 times that of Earth, or 0.74 times the radius of Jupiter. Its mass is 39.3 times that of Earth, giving it a density of 0.39 g/cm³ — closer to gas planets like Jupiter (1.33 g/cm³).
Is HD 148797 b in the Habitable Zone?
HD 148797 b orbits inside the inner edge of the habitable zone of HD 148797. So close to its star, surface conditions are far too hot for liquid water.
Habitable zone of HD 148797: 1.409–3.274 AU (conservative: 1.785–3.104 AU), per Kopparapu et al. (2014). Earth orbits the Sun at 1 AU.
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Temperature on HD 148797 b
The equilibrium temperature of HD 148797 b is about 762 K (489 °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 HD 148797 b — one full orbit around HD 148797 — lasts 42.1 Earth days, shorter than Mercury's 88-day year. It orbits at an average distance of 0.257 AU — closer to its star than Mercury is to the Sun. Its orbit is mildly elliptical (eccentricity 0.15).
How Was HD 148797 b Discovered?
HD 148797 b was discovered in 2026 using the transit method, with observations from Transiting Exoplanet Survey Satellite (TESS).
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 HD 148797 b?
HD 148797 b is 562.2 light-years (172.4 parsecs) from Earth. Light arriving here tonight left the planet around the year 1464. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 9,894,720 years to make the journey.
The Host Star: HD 148797
HD 148797
- Spectral type
- F6
- Surface temperature
- 6,441 K (Sun: 5,772 K)
- Mass
- 1.27 M☉
- Radius
- 1.55 R☉
- Luminosity
- 3.8200 L☉
- Age
- 2.9 billion years (Sun: 4.6)
The HD 148797 Planetary System
HD 148797 b is one of 2 known planets in the HD 148797 system. Its siblings:
- HD 148797 c (Cold Gas Giant)
HD 148797 b — Complete Data
| Radius | 8.250 Earth radii (0.736 Jupiter radii) |
|---|---|
| Mass | 39.30 Earth masses (0.124 Jupiter masses) |
| Density | 0.39 g/cm³ (Earth: 5.51) |
| Orbital period | 42.10 days |
| Orbital distance | 0.257 AU |
| Eccentricity | 0.153 |
| Equilibrium temperature | 762 K (489 °C) |
| Distance from Earth | 562.2 light-years (172.4 parsecs) |
| Constellation | Norma |
| Discovery method | Transit |
| Discovery facility | Transiting Exoplanet Survey Satellite (TESS) |
| Discovery year | 2026 |
Data: NASA Exoplanet Archive, last updated 2026-10-01. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About HD 148797 b
Is HD 148797 b habitable?
No — HD 148797 b orbits too close to its star and is too hot for liquid water to exist on its surface.
How far away is HD 148797 b?
HD 148797 b is about 562 light-years from Earth in the constellation Norma. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 9,894,720 years to get there.
How big is HD 148797 b compared to Earth?
HD 148797 b has 8.25 times the radius of Earth and about 39.3 times its mass.
How long is a year on HD 148797 b?
One orbit around HD 148797 takes 42.1 Earth days.
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