Key parameters at a glance
- A radius of 6.39 Earth radii
- A mass of 69.92 Earth masses
- Surface gravity around 1.71 g
- An orbital period of 6.212 days
- Semi-major axis 0.0630 AU
- Equilibrium temperature 870 K (597 °C)
- Distance from Earth 1,050.34 light-years
- Earth Similarity Index 0.221
- Travel time at Voyager 1 speed 18,522,798 years
- Almost certainly tidally locked to its host star given the close orbit
CoRoT-8 b Planet Profile
Physical Specs
Classification
Planet Type
Neptune-like
Discovery
Size rank in cohort
Rank by radius
#250of 574
top 43.4%
This planet
6.39R⊕
Neptune-like median
6.39R⊕
Nearest-size peers
| Metric | Earth | CoRoT-8 b | Jupiter |
|---|---|---|---|
| Radius (R⊕) | 1.00 | 6.39 | 11.21 |
| Mass (M⊕) | 1.00 | 69.92 | 317.83 |
| Density (g/cm³) | 5.51 | 1.60 | 1.33 |
| Surface Gravity (g) | 1.00 | 1.71 | 2.53 |
| Insolation (S⊕) | 1.00 | — | 0.037 |
Alternative Mass Estimates
| Method | Value | Interpretation |
|---|---|---|
| Best measured mass | 69.920 M⊕ | Direct mass measurement (not derived). |
Star Catalogue Identifiers
TIC
TIC 391880567
Gaia DR2
Gaia DR2 4287832775526476800
Gaia DR3
Gaia DR3 4287832775526476800
System
CoRoT-8
Percentile among Neptune-like cohort
Orbit & Habitability
Orbital Dynamics
Year Length
A year here lasts approximately 6.21 Earth days (1.7% of a terrestrial year) on a nearly circular orbit at a mean orbital distance of 0.0630 AU.
Transit Fingerprint
Depth
0.651 %
Duration
2.740 h
Impact parameter b
0.490
Rp / R★
0.075000
Transit midpoint (BJD)
2,454,238.9743
Photometric dip
Transit produces a flux drop of 6,510 ppm lasting ≈ 2.74 h.
Extended Orbital Architecture
Planet / star radius ratio
0.075000
Semi-major axis / stellar radius
17.600
Impact parameter (b)
0.490
RV semi-amplitude (K)
26.000 m/s
Transit mid-time (BJD)
2,454,238.9743
Angular separation (arcsec)
0.19600
Eq. Temperature
870K
(597 °C)
Insolation (S⊕)
—
Earth = 1.00
Earth Similarity (ESI)
0.221
0 = alien, 1 = Earth-identical
Insufficient insolation data — the surface is too hot to retain surface water. 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
Borde et al. 2010Instrument
CoRoT CCD Array
Publication
2010-09
Observation locale
Space
Discovery cohort
Planets confirmed in 2010 at CoRoT (5 shown).
Host System: CoRoT-8
Spectral Class
K-type orange
Effective Temperature
5,080 K — cooler than the Sun (5,778 K)
Estimated Age
3.00 Gyr — younger than the Sun (4.6 Gyr)
Stellar Radius
0.770 R☉
Stellar Mass
0.880 M☉
Metallicity [Fe/H]
0.30
Extended Stellar Properties
Surface gravity (log g)
4.580 dex
Stellar density
2.700 g/cm³
Systemic radial velocity
-37.47 km/s
Rotational v·sin i
2.00 km/s
Metallicity ratio
[M/H]
Multi-band Host Photometry — 13 bands
Astrometric Data
Parallax
3.077 mas
Total Proper Motion
35.483 mas/yr
PM Right Ascension
13.58 mas/yr
PM Declination
-32.78 mas/yr
Galactic Cartesian (pc)
x = 0.368 · y = -0.930 · z = 0.025
Equatorial (J2000)
RA 291.58857° · Dec 1.42630°
Galactic ℓ, b
38.213° · -7.104°
Ecliptic λ, β
293.570° · 23.116°
HTM-20 index
188903117
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