HD 173416 b
HD 173416 b is a cold gas giant orbiting the G8 star HD 173416 in the constellation Lyra. It lies about 431 light-years from Earth and was discovered in 2008 using the radial velocity method.
Is HD 173416 b in the Habitable Zone?
HD 173416 b orbits inside the inner edge of the habitable zone of HD 173416. So close to its star, surface conditions are far too hot for liquid water.
Habitable zone of HD 173416: 7.014–17.185 AU (conservative: 8.884–16.293 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 ›
Orbit and Year Length
A year on HD 173416 b — one full orbit around HD 173416 — lasts 322.0 Earth days, between the years of Mercury (88 days) and Earth (365 days). It orbits at an average distance of 1.158 AU. Its orbit is mildly elliptical (eccentricity 0.21).
How Was HD 173416 b Discovered?
HD 173416 b was discovered in 2008 using the radial velocity method, with observations from Xinglong Station.
The radial velocity method measures the subtle wobble of a star caused by the gravitational pull of an orbiting planet, visible as periodic shifts in the star's light spectrum. The size of the wobble reveals the planet's minimum mass.
How Far Away Is HD 173416 b?
HD 173416 b is 431.1 light-years (132.2 parsecs) from Earth. Light arriving here tonight left the planet around the year 1595. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 7,587,360 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 173416 b scores 0.08, ranking #4,585 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: HD 173416
HD 173416
- Spectral type
- G8
- Surface temperature
- 4,683 K (Sun: 5,772 K)
- Mass
- 2.00 M☉
- Radius
- 13.50 R☉
- Luminosity
- 77.9830 L☉
Planetary System
HD 173416 b is the only planet known to orbit HD 173416 so far.
HD 173416 b — Complete Data
| Mass (best estimate) | 585.12 Earth masses |
|---|---|
| Orbital period | 322.03 days |
| Orbital distance | 1.158 AU |
| Eccentricity | 0.208 |
| Earth Similarity Index | 0.08 |
| Distance from Earth | 431.1 light-years (132.2 parsecs) |
| Constellation | Lyra |
| Discovery method | Radial Velocity |
| Discovery facility | Xinglong Station |
| Discovery year | 2008 |
Data: NASA Exoplanet Archive, last updated 2023-09-19. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About HD 173416 b
Is HD 173416 b habitable?
No — HD 173416 b orbits too close to its star and is too hot for liquid water to exist on its surface.
How far away is HD 173416 b?
HD 173416 b is about 431 light-years from Earth in the constellation Lyra. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 7,587,360 years to get there.
How long is a year on HD 173416 b?
One orbit around HD 173416 takes 322.0 Earth days.
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