17 Sco b
17 Sco b is a cold gas giant orbiting the K3 III star 17 Sco in the constellation Scorpius. It lies about 408 light-years from Earth and was discovered in 2020 using the radial velocity method.
Is 17 Sco b in the Habitable Zone?
17 Sco b orbits inside the inner edge of the habitable zone of 17 Sco. So close to its star, surface conditions are far too hot for liquid water.
Habitable zone of 17 Sco: 10.830–27.199 AU (conservative: 13.717–25.787 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 17 Sco b — one full orbit around 17 Sco — lasts 578.4 Earth days, longer than an Earth year. It orbits at an average distance of 1.450 AU. Its orbit is mildly elliptical (eccentricity 0.06).
How Was 17 Sco b Discovered?
17 Sco b was discovered in 2020 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 17 Sco b?
17 Sco b is 407.5 light-years (125.0 parsecs) from Earth. Light arriving here tonight left the planet around the year 1619. A probe traveling at the speed of Voyager 1 — about 17 km/s, the fastest outbound spacecraft ever launched — would need roughly 7,172,000 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. 17 Sco b scores 0.08, ranking #4,635 of 5,568 planets with a known ESI. For reference, Mars scores about 0.70.
The Host Star: 17 Sco
17 Sco
- Spectral type
- K3 III
- Surface temperature
- 4,157 K (Sun: 5,772 K)
- Mass
- 1.22 M☉
- Radius
- 25.92 R☉
- Luminosity
- 179.6181 L☉
- Age
- 5.1 billion years (Sun: 4.6)
Planetary System
17 Sco b is the only planet known to orbit 17 Sco so far.
17 Sco b — Complete Data
| Mass (best estimate) | 1,373.02 Earth masses |
|---|---|
| Orbital period | 578.38 days |
| Orbital distance | 1.450 AU |
| Eccentricity | 0.060 |
| Earth Similarity Index | 0.08 |
| Distance from Earth | 407.5 light-years (125.0 parsecs) |
| Constellation | Scorpius |
| Discovery method | Radial Velocity |
| Discovery facility | Lick Observatory |
| Discovery year | 2020 |
Data: NASA Exoplanet Archive, last updated 2021-10-25. Earth Similarity Index: PHL @ UPR Arecibo.
Frequently Asked Questions About 17 Sco b
Is 17 Sco b habitable?
No — 17 Sco b orbits too close to its star and is too hot for liquid water to exist on its surface.
How far away is 17 Sco b?
17 Sco b is about 408 light-years from Earth in the constellation Scorpius. A spacecraft traveling as fast as Voyager 1 (about 17 km/s) would need roughly 7,172,000 years to get there.
How long is a year on 17 Sco b?
One orbit around 17 Sco takes 578.4 Earth days.
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