Gas giant · XO-2 S

XO-2 S b

ExoplanetsDiscovered 2014

Scientific overview

XO-2 S b is a gas giant orbiting XO-2 S, completing an orbit every 18 days, about 494 light-years from Earth. It was discovered in 2014 using the radial velocity method.

Host star

XO-2 S

Spectral type

G8 V

Temperature

5,325 K

Mass

0.98 M☉

Planetary system — XO-2 S system

View the XO-2 S system (3 known planets).

Planet	Class	Radius (R⊕)	Period (d)	Distance (ly)
XO-2 S bRadial Velocity · 2014	Gas giant	10.9	18.22	494
XO-2 S cRadial Velocity · 2014	Gas giant	13.6	120	494
XO-2 S dRadial Velocity · 2024	Gas giant	13	4696	494

Discovery and detection

Detection method

Radial Velocity Method

Discovery year

2014

Discovered at

Roque de los Muchachos Observatory

Knowledge connections

OrbitsXO-2 S
Member of systemXO-2 S system
Discovered by methodRadial Velocity Method
Discovered atRoque de los Muchachos Observatory
Catalogued inNASA Exoplanet Archive

Quick facts

Class: Gas giant
Host star: XO-2 S
Discovery method: Radial Velocity Method
Discovery year: 2014
Orbital period: 18.22 d
Semi-major axis: 0.1347 AU
Eccentricity: 0.15
Radius: 10.9 R⊕
Mass: 82.64 M⊕
Density: 0.35 g/cm³ · derived
Equilibrium temp.: 707 K
Insolation: 41.52 S⊕
Distance: 494 ly

Density is derived from the archive mass and radius via ρ = M / (4⁄3·π·r³); all other values are catalogued measurements.

Derived values

Computed from source-backed inputs via standard formulae — not observations. Every input and constant is traced below.

Bulk density0.35 g/cm³derived
Formula & inputs
Formula: ρ = M / (4⁄3·π·r³) (v1.0.0, impl v1.0.0)
Inputs:
- massEarth = 82.64 M⊕ · NASA
- radiusEarth = 10.9 R⊕ · NASA
Assumptions: M⊕ = 5.972e+24 kg, R⊕ = 6371000 m (IAU 2015 B3 nominal); Assumes a uniform sphere.
Limitations: Withheld above 30 g/cm³ (inconsistent mass/radius inputs).; Archive mass/radius carry no propagated uncertainty here.
Uncertainty: not propagated (inputs carry no catalogued uncertainty)
Computed as of 2026-06-29.

Quality & authority

Partial

Unreviewed

Description: Complete
Source coverage: Partial
Relationship coverage: Complete
Review coverage: None
Citation coverage: None
Image coverage: Not applicable

Data from the NASA Exoplanet Archive. See source quality.