Key parameters at a glance
- A radius of 11.13 Earth radii
- A mass of 179.89 Earth masses
- Surface gravity around 1.45 g
- An orbital period of 2.616 days
- Semi-major axis 0.0368 AU
- Equilibrium temperature 1,328 K (1055 °C)
- Distance from Earth 503.17 light-years
- Earth Similarity Index 0.105
- Travel time at Voyager 1 speed 8,873,414 years
- Almost certainly tidally locked to its host star given the close orbit
XO-2 N b Planet Profile
Physical Specs
Classification
Planet Type
Gas Giant
Discovery
Size rank in cohort
Rank by radius
#1646of 1771
top 92.9%
This planet
11.13R⊕
Gas Giant median
13.52R⊕
Nearest-size peers
| Metric | Earth | XO-2 N b | Jupiter |
|---|---|---|---|
| Radius (R⊕) | 1.00 | 11.13 | 11.21 |
| Mass (M⊕) | 1.00 | 179.89 | 317.83 |
| Density (g/cm³) | 5.51 | 0.72 | 1.33 |
| Surface Gravity (g) | 1.00 | 1.45 | 2.53 |
| Insolation (S⊕) | 1.00 | 428.04 | 0.037 |
Alternative Mass Estimates
| Method | Value | Interpretation |
|---|---|---|
| Best measured mass | 179.892 M⊕ | Direct mass measurement (not derived). |
Star Catalogue Identifiers
TIC
TIC 356473034
Gaia DR2
Gaia DR2 934346809278715776
Gaia DR3
Gaia DR3 934346809278715776
System
XO-2
Percentile among Gas Giant cohort
Orbit & Habitability
Orbital Dynamics
Year Length
A year here lasts approximately 2.62 Earth days (0.7% of a terrestrial year) on a nearly circular orbit at a mean orbital distance of 0.0368 AU.
Transit Fingerprint
Depth
1.336 %
Duration
2.684 h
Impact parameter b
0.280
Rp / R★
0.103040
Transit midpoint (BJD)
2,454,508.7383
Photometric dip
Transit produces a flux drop of 13,363 ppm lasting ≈ 2.68 h.
Extended Orbital Architecture
Planet / star radius ratio
0.103040
Semi-major axis / stellar radius
7.986
Impact parameter (b)
0.280
RV semi-amplitude (K)
90.170 m/s
Transit mid-time (BJD)
2,454,508.7383
Long. of periastron (ω)
261.00°
Sky-projected obliquity (λ)
7.00°
True obliquity (ψ)
27.00°
Angular separation (arcsec)
0.23900
Eq. Temperature
1,328K
(1055 °C)
Insolation (S⊕)
428.04
Earth = 1.00
Earth Similarity (ESI)
0.105
0 = alien, 1 = Earth-identical
Inside the inner HZ boundary (too hot for liquid water) — the dayside is scorched. Close-orbiting tidally-locked around a cool host.
Detection Signatures
Transit photometry
A transit dip has been observed from at least one telescope.
Radial velocity
Stellar wobble has been measured spectroscopically.
Discovery Paper
Primary reference
Burke et al. 2007Instrument
Apogee CCD Array
Publication
2007-12
Observation locale
Ground
Host System: XO-2 N
Spectral Class
K-type orange
Effective Temperature
5,340 K — cooler than the Sun (5,778 K)
Estimated Age
7.80 Gyr — older than the Sun (4.6 Gyr)
Stellar Radius
0.990 R☉
Stellar Mass
0.971 M☉
Metallicity [Fe/H]
0.43
Extended Stellar Properties
Surface gravity (log g)
4.433 dex
Stellar density
1.410 g/cm³
Systemic radial velocity
46.93 km/s
Rotational v·sin i
1.07 km/s
Rotation period
28.60 days
Multi-band Host Photometry — 17 bands
Astrometric Data
Parallax
6.454 mas
Total Proper Motion
157.111 mas/yr
PM Right Ascension
-29.73 mas/yr
PM Declination
-154.27 mas/yr
Galactic Cartesian (pc)
x = -0.291 · y = 0.570 · z = 0.769
Equatorial (J2000)
RA 117.02677° · Dec 50.22515°
Galactic ℓ, b
168.290° · 29.328°
Ecliptic λ, β
109.330° · 28.584°
HTM-20 index
-142096766
Observation Record
Photometric series
42
RV measurements
3
Transmission spectra
5
Emission spectra
3
Archive notes
3
Similar Worlds
TOI-1811 b
Gas Giant · K-type orange
Radius 11.14 R⊕ · 418.2 ly
HAT-P-18 b
Gas Giant · K-type orange
Radius 11.15 R⊕ · 526.4 ly
TOI-4504 c
Gas Giant · K-type orange
Radius 11.10 R⊕ · 1,117.4 ly
WASP-80 b
Gas Giant · K-type orange
Radius 11.20 R⊕ · 162.4 ly
WASP-162 b
Gas Giant · K-type orange
Radius 11.21 R⊕ · 1,013.8 ly
WASP-69 b
Gas Giant · K-type orange
Radius 11.21 R⊕ · 162.9 ly