Key parameters at a glance
- A radius of 14.80 Earth radii
- A mass of 4,217.58 Earth masses
- Surface gravity around 19.27 g
- An orbital period of 3.192 days
- Semi-major axis 0.0482 AU
- Equilibrium temperature 1,890 K (1617 °C)
- Distance from Earth 694.89 light-years
- Earth Similarity Index 0.076
- Travel time at Voyager 1 speed 12,254,299 years
XO-3 b Planet Profile
Physical Specs
Classification
Planet Type
Gas Giant
Discovery
Size rank in cohort
Rank by radius
#254of 1771
top 14.3%
This planet
14.80R⊕
Gas Giant median
13.52R⊕
Nearest-size peers
| Metric | Earth | XO-3 b | Jupiter |
|---|---|---|---|
| Radius (R⊕) | 1.00 | 14.80 | 11.21 |
| Mass (M⊕) | 1.00 | 4,217.58 | 317.83 |
| Density (g/cm³) | 5.51 | 7.16 | 1.33 |
| Surface Gravity (g) | 1.00 | 19.27 | 2.53 |
| Insolation (S⊕) | 1.00 | 1,161.72 | 0.037 |
Alternative Mass Estimates
| Method | Value | Interpretation |
|---|---|---|
| Best measured mass | 4,217.583 M⊕ | Direct mass measurement (not derived). |
| Minimum mass (M sin i) | 4,138.126 M⊕ | Lower bound from radial-velocity fitting. |
Star Catalogue Identifiers
TIC
TIC 8400842
Gaia DR2
Gaia DR2 470650560777348352
Gaia DR3
Gaia DR3 470650560779277952
System
XO-3
Percentile among Gas Giant cohort
Orbit & Habitability
Orbital Dynamics
Year Length
A year here lasts approximately 3.19 Earth days (0.9% of a terrestrial year) on a mildly elliptical path at a mean orbital distance of 0.0481 AU.
Transit Fingerprint
Depth
0.820 %
Duration
2.964 h
Impact parameter b
0.730
Rp / R★
0.089050
Transit midpoint (BJD)
2,457,424.9879
Photometric dip
Transit produces a flux drop of 8,200 ppm lasting ≈ 2.96 h.
Extended Orbital Architecture
Planet / star radius ratio
0.089050
Semi-major axis / stellar radius
6.797
Impact parameter (b)
0.730
RV semi-amplitude (K)
1,471.800 m/s
Transit mid-time (BJD)
2,457,424.9879
Long. of periastron (ω)
-10.84°
Sky-projected obliquity (λ)
40.20°
Angular separation (arcsec)
0.22600
Eq. Temperature
1,890K
(1617 °C)
Insolation (S⊕)
1,161.72
Earth = 1.00
Earth Similarity (ESI)
0.076
0 = alien, 1 = Earth-identical
Inside the inner HZ boundary (too hot for liquid water) — the dayside is scorched.
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
Johns Krull et al. 2008Instrument
Apogee CCD Array
Publication
2008-04
Observation locale
Ground
Host System: XO-3
Spectral Class
F-type yellow-white
Effective Temperature
6,970 K — hotter than the Sun (5,778 K)
Estimated Age
0.97 Gyr — younger than the Sun (4.6 Gyr)
Stellar Radius
1.523 R☉
Stellar Mass
1.449 M☉
Metallicity [Fe/H]
-0.16
Extended Stellar Properties
Surface gravity (log g)
4.234 dex
Stellar density
0.578 g/cm³
Systemic radial velocity
-12.03 km/s
Rotational v·sin i
18.63 km/s
Metallicity ratio
[Fe/H]
Multi-band Host Photometry — 11 bands
Astrometric Data
Parallax
4.666 mas
Total Proper Motion
4.728 mas/yr
PM Right Ascension
-2.52 mas/yr
PM Declination
4.00 mas/yr
Galactic Cartesian (pc)
x = 0.221 · y = 0.485 · z = 0.846
Equatorial (J2000)
RA 65.46958° · Dec 57.81721°
Galactic ℓ, b
148.097° · 5.628°
Ecliptic λ, β
74.192° · 35.716°
HTM-20 index
-2112513671
Observation Record
Photometric series
50
RV measurements
4
Emission spectra
21
Archive notes
2
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