HIP 65 A b
HIP 65 A b is a hot Jupiter orbiting the K4 V star HIP 65 A in the constellation Phoenix. It lies about 202 light-years from Earth and was discovered in 2020 using the transit method.
How Big Is HIP 65 A b?
HIP 65 A b has a radius of 22.75 times that of Earth, or 2.03 times the radius of Jupiter. Its mass is 1,021 times that of Earth, giving it a density of 0.48 g/cm³ — closer to gas planets like Jupiter (1.33 g/cm³).
Is HIP 65 A b in the Habitable Zone?
HIP 65 A b orbits inside the inner edge of the habitable zone of HIP 65 A. So close to its star, surface conditions are far too hot for liquid water.
Habitable zone of HIP 65 A: 0.365–0.899 AU (conservative: 0.463–0.852 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 ›
Temperature on HIP 65 A b
The equilibrium temperature of HIP 65 A b is about 1,411 K (1,138 °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 661 times the stellar energy that Earth gets from the Sun.
Orbit and Year Length
A year on HIP 65 A b — one full orbit around HIP 65 A — lasts just 23.5 hours, shorter than Mercury's 88-day year. It orbits at an average distance of 0.018 AU — closer to its star than Mercury is to the Sun.
How Was HIP 65 A b Discovered?
HIP 65 A b was discovered in 2020 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 HIP 65 A b?
HIP 65 A b is 201.5 light-years (61.8 parsecs) from Earth. Light arriving here tonight left the planet around the year 1825. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 3,546,400 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. HIP 65 A b scores 0.04, ranking #5,316 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: HIP 65 A
HIP 65 A b belongs to a system of 2 stars; it orbits HIP 65 A.
HIP 65 A
- Spectral type
- K4 V
- Surface temperature
- 4,590 K (Sun: 5,772 K)
- Mass
- 0.78 M☉
- Radius
- 0.72 R☉
- Luminosity
- 0.2099 L☉
- Age
- 4.1 billion years (Sun: 4.6)
Planetary System
HIP 65 A b is the only planet known to orbit HIP 65 A so far.
HIP 65 A b — Complete Data
| Radius | 22.754 Earth radii (2.030 Jupiter radii) |
|---|---|
| Mass | 1,021.19 Earth masses (3.213 Jupiter masses) |
| Density | 0.48 g/cm³ (Earth: 5.51) |
| Orbital period | 0.98 days |
| Orbital distance | 0.018 AU |
| Equilibrium temperature | 1,411 K (1,138 °C) |
| Stellar irradiation | 661.00× Earth |
| Earth Similarity Index | 0.04 |
| Distance from Earth | 201.5 light-years (61.8 parsecs) |
| Constellation | Phoenix |
| Discovery method | Transit |
| Discovery facility | Transiting Exoplanet Survey Satellite (TESS) |
| Discovery year | 2020 |
Data: NASA Exoplanet Archive, last updated 2020-07-17. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About HIP 65 A b
Is HIP 65 A b habitable?
No — HIP 65 A b orbits too close to its star and is too hot for liquid water to exist on its surface.
How far away is HIP 65 A b?
HIP 65 A b is about 202 light-years from Earth in the constellation Phoenix. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 3,546,400 years to get there.
How big is HIP 65 A b compared to Earth?
HIP 65 A b has 22.75 times the radius of Earth and about 1,021 times its mass.
How long is a year on HIP 65 A b?
One orbit around HIP 65 A takes 1.0 Earth days — short enough that 372 of its years would fit into one Earth year.
Explore HIP 65 A b in the app
Browse, filter and compare 6,000+ exoplanets on iPhone, iPad and Apple Watch — with habitable-zone views, widgets and offline data.
