HD 221416 b
HD 221416 b is a cold gas giant orbiting HD 221416 in the constellation Aquarius. It lies about 312 light-years from Earth and was discovered in 2019 using the transit method.
How Big Is HD 221416 b?
HD 221416 b has a radius of 9.17 times that of Earth, or 0.84 times the radius of Jupiter. Its mass is 60.5 times that of Earth, giving it a density of 0.43 g/cm³ — closer to gas planets like Jupiter (1.33 g/cm³).
Is HD 221416 b in the Habitable Zone?
HD 221416 b orbits inside the inner edge of the habitable zone of HD 221416. So close to its star, surface conditions are far too hot for liquid water.
Habitable zone of HD 221416: 1.771–4.268 AU (conservative: 2.243–4.046 AU), per Kopparapu et al. (2014). Earth orbits the Sun at 1 AU.
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Orbit and Year Length
A year on HD 221416 b — one full orbit around HD 221416 — lasts 14.3 Earth days, shorter than Mercury's 88-day year. It orbits at an average distance of 0.123 AU — closer to its star than Mercury is to the Sun. Its orbit is mildly elliptical (eccentricity 0.12).
How Was HD 221416 b Discovered?
HD 221416 b was discovered in 2019 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 221416 b?
HD 221416 b is 311.6 light-years (95.5 parsecs) from Earth. Light arriving here tonight left the planet around the year 1715. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 5,484,160 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. HD 221416 b scores 0.10, ranking #4,468 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: HD 221416
HD 221416
- Surface temperature
- 5,080 K (Sun: 5,772 K)
- Mass
- 1.21 M☉
- Radius
- 2.94 R☉
- Luminosity
- 5.1500 L☉
- Age
- 4.9 billion years (Sun: 4.6)
Planetary System
HD 221416 b is the only planet known to orbit HD 221416 so far.
HD 221416 b — Complete Data
| Radius | 9.170 Earth radii (0.836 Jupiter radii) |
|---|---|
| Mass | 60.50 Earth masses (0.190 Jupiter masses) |
| Density | 0.43 g/cm³ (Earth: 5.51) |
| Orbital period | 14.28 days |
| Orbital distance | 0.123 AU |
| Eccentricity | 0.115 |
| Earth Similarity Index | 0.10 |
| Distance from Earth | 311.6 light-years (95.5 parsecs) |
| Constellation | Aquarius |
| Discovery method | Transit |
| Discovery facility | Transiting Exoplanet Survey Satellite (TESS) |
| Discovery year | 2019 |
Data: NASA Exoplanet Archive, last updated 2019-04-16. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About HD 221416 b
Is HD 221416 b habitable?
No — HD 221416 b orbits too close to its star and is too hot for liquid water to exist on its surface.
How far away is HD 221416 b?
HD 221416 b is about 312 light-years from Earth in the constellation Aquarius. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 5,484,160 years to get there.
How big is HD 221416 b compared to Earth?
HD 221416 b has 9.17 times the radius of Earth and about 60.5 times its mass.
How long is a year on HD 221416 b?
One orbit around HD 221416 takes 14.3 Earth days — short enough that 26 of its years would fit into one Earth year.
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