HD 195019 b
HD 195019 b is a cold gas giant orbiting HD 195019 in the constellation Delphinus. It lies about 123 light-years from Earth and was discovered in 1998 using the radial velocity method.
Is HD 195019 b in the Habitable Zone?
HD 195019 b orbits inside the inner edge of the habitable zone of HD 195019. So close to its star, surface conditions are far too hot for liquid water.
Habitable zone of HD 195019: 1.102–2.598 AU (conservative: 1.396–2.464 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 195019 b — one full orbit around HD 195019 — lasts 18.2 Earth days, shorter than Mercury's 88-day year. It orbits at an average distance of 0.140 AU — closer to its star than Mercury is to the Sun. Its orbit is nearly circular (eccentricity 0.010).
How Was HD 195019 b Discovered?
HD 195019 b was discovered in 1998 using the radial velocity method, with observations from Lick Observatory.
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 195019 b?
HD 195019 b is 122.9 light-years (37.7 parsecs) from Earth. Light arriving here tonight left the planet around the year 1904. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 2,163,040 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 195019 b scores 0.08, ranking #4,703 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: HD 195019
HD 195019 b belongs to a system of 2 stars; it orbits HD 195019.
HD 195019
- Surface temperature
- 5,751 K (Sun: 5,772 K)
- Mass
- 1.21 M☉
- Radius
- 1.48 R☉
Planetary System
HD 195019 b is the only planet known to orbit HD 195019 so far.
HD 195019 b — Complete Data
| Mass (best estimate) | 1,264.96 Earth masses |
|---|---|
| Orbital period | 18.20 days |
| Orbital distance | 0.140 AU |
| Eccentricity | 0.010 |
| Earth Similarity Index | 0.08 |
| Distance from Earth | 122.9 light-years (37.7 parsecs) |
| Constellation | Delphinus |
| Discovery method | Radial Velocity |
| Discovery facility | Lick Observatory |
| Discovery year | 1998 |
Data: NASA Exoplanet Archive, last updated 2018-09-04. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About HD 195019 b
Is HD 195019 b habitable?
No — HD 195019 b orbits too close to its star and is too hot for liquid water to exist on its surface.
How far away is HD 195019 b?
HD 195019 b is about 123 light-years from Earth in the constellation Delphinus. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 2,163,040 years to get there.
How long is a year on HD 195019 b?
One orbit around HD 195019 takes 18.2 Earth days — short enough that 20 of its years would fit into one Earth year.
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