Key parameters at a glance
- A radius of 19.66 Earth radii
- A mass of 137.30 Earth masses
- Surface gravity around 0.36 g
- An orbital period of 4.438 days
- Semi-major axis 0.0553 AU
- Equilibrium temperature 1,480 K (1207 °C)
- Distance from Earth 2,874.69 light-years
- Earth Similarity Index 0.057
- Travel time at Voyager 1 speed 50,695,214 years
Kepler-12 b Planet Profile
Physical Specs
Classification
Planet Type
Gas Giant
Discovery
Size rank in cohort
Rank by radius
#34of 1771
top 1.9%
This planet
19.66R⊕
Gas Giant median
13.52R⊕
Nearest-size peers
| Metric | Earth | Kepler-12 b | Jupiter |
|---|---|---|---|
| Radius (R⊕) | 1.00 | 19.66 | 11.21 |
| Mass (M⊕) | 1.00 | 137.30 | 317.83 |
| Density (g/cm³) | 5.51 | 0.11 | 1.33 |
| Surface Gravity (g) | 1.00 | 0.36 | 2.53 |
| Insolation (S⊕) | 1.00 | 877.54 | 0.037 |
Alternative Mass Estimates
| Method | Value | Interpretation |
|---|---|---|
| Best measured mass | 137.303 M⊕ | Direct mass measurement (not derived). |
Star Catalogue Identifiers
TIC
TIC 405717754
Gaia DR2
Gaia DR2 2133599775377340672
Gaia DR3
Gaia DR3 2133599775377340672
System
Kepler-12
Percentile among Gas Giant cohort
Orbit & Habitability
Orbital Dynamics
Year Length
A year here lasts approximately 4.44 Earth days (1.2% of a terrestrial year) on a nearly circular orbit at a mean orbital distance of 0.0553 AU.
Transit Fingerprint
Depth
1.672 %
Duration
4.698 h
Impact parameter b
0.168
Rp / R★
0.118867
Transit midpoint (BJD)
2,455,004.0092
Photometric dip
Transit produces a flux drop of 16,721 ppm lasting ≈ 4.70 h.
Extended Orbital Architecture
Planet / star radius ratio
0.118867
Semi-major axis / stellar radius
8.019
Impact parameter (b)
0.168
RV semi-amplitude (K)
48.200 m/s
Occultation depth
0.002 ppm
Transit mid-time (BJD)
2,455,004.0092
Long. of periastron (ω)
182.00°
Angular separation (arcsec)
0.06270
Eq. Temperature
1,480K
(1207 °C)
Insolation (S⊕)
877.54
Earth = 1.00
Earth Similarity (ESI)
0.057
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.
Orbital-brightness modulation
Host star brightness varies with the planet's orbit.
Discovery Paper
Primary reference
Fortney et al. 2011Instrument
Kepler CCD Array
Publication
2011-11
Observation locale
Space
Discovery cohort
Planets confirmed in 2011 at Kepler (12 shown).
Host System: Kepler-12
Spectral Class
G-type yellow (Sun-like)
Effective Temperature
5,947 K — hotter than the Sun (5,778 K)
Estimated Age
4.00 Gyr — younger than the Sun (4.6 Gyr)
Stellar Radius
1.483 R☉
Stellar Mass
1.166 M☉
Metallicity [Fe/H]
0.07
Extended Stellar Properties
Surface gravity (log g)
4.175 dex
Stellar density
0.508 g/cm³
Rotational v·sin i
0.80 km/s
Metallicity ratio
[Fe/H]
Multi-band Host Photometry — 16 bands
Astrometric Data
Parallax
1.106 mas
Total Proper Motion
4.448 mas/yr
PM Right Ascension
3.05 mas/yr
PM Declination
3.24 mas/yr
Galactic Cartesian (pc)
x = 0.180 · y = -0.617 · z = 0.766
Equatorial (J2000)
RA 286.24345° · Dec 50.04037°
Galactic ℓ, b
80.423° · 18.407°
Ecliptic λ, β
304.553° · 71.536°
HTM-20 index
386376558
Similar Worlds
KELT-14 b
Gas Giant · G-type yellow (Sun-like)
Radius 19.54 R⊕ · 815.8 ly
TOI-2193 A b
Gas Giant · G-type yellow (Sun-like)
Radius 19.84 R⊕ · 1,099.4 ly
TOI-3807 b
Gas Giant · G-type yellow (Sun-like)
Radius 18.49 R⊕ · 1,375.5 ly
TOI-1855 b
Gas Giant · G-type yellow (Sun-like)
Radius 18.49 R⊕ · 576.8 ly
Kepler-447 b
Gas Giant · G-type yellow (Sun-like)
Radius 18.49 R⊕ · 874.2 ly
HATS-23 b
Gas Giant · G-type yellow (Sun-like)
Radius 20.85 R⊕ · 2,084.1 ly