HD 164604 b
HD 164604 b is a exoplanet orbiting the K3.5 V star HD 164604 in the constellation Sagittarius. It lies about 128 light-years from Earth and was discovered in 2009 using the radial velocity method.
Is HD 164604 b in the Habitable Zone?
HD 164604 b orbits beyond the outer edge of the habitable zone of HD 164604. At that distance, any surface water would almost certainly be frozen.
Habitable zone of HD 164604: 0.405–0.994 AU (conservative: 0.513–0.942 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 164604 b — one full orbit around HD 164604 — lasts 653.9 Earth days, longer than an Earth year. It orbits at an average distance of 1.362 AU. Its orbit is highly elliptical (eccentricity 0.48), swinging dramatically closer to and farther from its star.
How Was HD 164604 b Discovered?
HD 164604 b was discovered in 2009 using the radial velocity method, with observations from Las Campanas 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 164604 b?
HD 164604 b is 128.4 light-years (39.4 parsecs) from Earth. Light arriving here tonight left the planet around the year 1898. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 2,259,840 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 164604 b scores 0.20, ranking #3,865 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: HD 164604
HD 164604
- Spectral type
- K3.5 V
- Surface temperature
- 4,663 K (Sun: 5,772 K)
- Mass
- 0.77 M☉
- Radius
- 0.78 R☉
- Luminosity
- 0.2600 L☉
- Age
- 1.6 billion years (Sun: 4.6)
The HD 164604 Planetary System
HD 164604 b is one of 2 known planets in the HD 164604 system. Its siblings:
- HD 164604 c (Cold Gas Giant)
HD 164604 b — Complete Data
| Mass | 4,195.33 Earth masses (13.200 Jupiter masses) |
|---|---|
| Orbital period | 653.90 days |
| Orbital distance | 1.362 AU |
| Eccentricity | 0.479 |
| Earth Similarity Index | 0.20 |
| Distance from Earth | 128.4 light-years (39.4 parsecs) |
| Constellation | Sagittarius |
| Discovery method | Radial Velocity |
| Discovery facility | Las Campanas Observatory |
| Discovery year | 2009 |
Data: NASA Exoplanet Archive, last updated 2026-02-26. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About HD 164604 b
Is HD 164604 b habitable?
No — HD 164604 b orbits outside the habitable zone of HD 164604 and is likely too cold for liquid water on its surface.
How far away is HD 164604 b?
HD 164604 b is about 128 light-years from Earth in the constellation Sagittarius. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 2,259,840 years to get there.
How long is a year on HD 164604 b?
One orbit around HD 164604 takes 653.9 Earth days.
Explore HD 164604 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.
