Finding Earth 2.0
Kepler-1229

Kepler-1229 b

Rank #8 of the ranked catalogue · Discovered by Transit in 2016

HZ 100%inferred

0.716

Earth-2.0 index

rank #8

0.819

Earth Similarity Index

0.792–0.842 (68% CI)

100%

Conservative HZ probability

1.40 R⊕

Radius

mass: inferred_mass_radius

At a glance

Kepler-1229 lies 865.89 light-years (265.482 pc) from the Sun. Kepler-1229 is the host star with 0.54× the Sun's mass and 0.51× its radius (effective temperature 3784 K, versus the Sun's 5772 K). It is a single star hosting 1 known planet. Kepler-1229 b is 1.4× Earth's radius, an estimated 2.54× Earth's mass, inferred from its radius rather than measured, completing one orbit every 86.8 days at 0.3006 AU. It receives about 0.52× the flux Earth gets from the Sun, for an equilibrium temperature near 216 K (Earth's is 254 K).

Orbit and habitable-zone boundaries computed in Python from this system’s actual parameters. Sizes and the overall scale are compressed for visibility, not literal; green = conservative HZ, gold = optimistic HZ.

Planet parameters
Radius1.400 R⊕+0.110 / -0.130
Mass2.540 M⊕inferredNOT measured. Predicted from the radius by a mass-radius relation, so it carries no information beyond the radius.
Bulk density5.090 g/cm³source: catalogue
Escape velocity15.07 km/s
Orbital period86.8290 days
Semi-major axis0.30060 au
Eccentricity0.000
Incident flux0.524 S⊕source: catalogue
Equilibrium temperature216.3 KBond albedo assumed: 0.306. Equilibrium temperature excludes greenhouse warming by construction. Earth's is 254 K against a 288 K surface.
Host star
NameKepler-1229
Spectral typeK
Effective temperature3784 K
Radius0.510 R☉
Mass0.540 M☉
Luminosity10^-1.533 L☉
Metallicity [Fe/H]-0.060
Age3.72 Gyr
Distance265.5 pc / 865.9 ly
Multiplicity1 star(s), 1 known planet(s)
Gaia DR3 cross-check
Parallax distance268.23 pc1.03% vs. archive-adopted distance
RUWE1.675RUWE > 1.4 is the conventional flag for a poorly-fit or unresolved-binary single-star astrometric solution.
Habitable zone
Boundary modelKopparapu et al. (2013), ApJ 765, 131, with the 2013 erratum coefficients
BoundaryS_eff (Earth units)
recent venus1.5455
runaway greenhouse0.8810
moist greenhouse0.8827
maximum greenhouse0.2541
early mars0.2292
Atmospheric spectroscopy

No published transmission spectrum exists for this planet in the NASA Exoplanet Archive.

Transit analysis
fit not validated

Fitted depth disagrees with the published value. In a multi-planet system this usually means the fold is contaminated by other planets' transits rather than isolating the target. This fit is NOT reported as a measurement.

Radial-velocity analysis

Not requested for this build.

Measurement sources
ParameterValueSource
Planet radius1.4000Morton et al. 2016
Planet mass2.5400archive-calculated (not a publication)
Orbital period86.8290Morton et al. 2016
Semi-major axis0.3006Torres et al. 2017
Incident flux0.5240Berger et al. 2018
Equilibrium temperature212.0000Torres et al. 2017
Bulk density5.0900archive-calculated (not a publication)
Orbital eccentricity0.0000Q1-Q17 DR25 KOI Table
Stellar effective temperature3784.0000Morton et al. 2016
Stellar radius0.5100Morton et al. 2016
Stellar mass0.5400Morton et al. 2016
Stellar luminosity-1.5330Torres et al. 2017
Stellar metallicity-0.0600Morton et al. 2016
Stellar age3.7200Morton et al. 2016
System distance265.4820TICv8

Component scores

Earth similarity

0.819

Conservative habitability

0.733

Observational confidence

0.571

Characterisation potential

0.209

Evidence

Independent references
11
Published parameter sets
11
Composite parameter sources
6 · mixed
Default-solution coverage
50%
Composite ↔ default difference
0% median
Uncertainty coverage
83%
Discovery method
Transit
Discovery year
2016

The archive composite selects values from multiple publications. This is disclosed separately and is not automatically penalised.

Observability

TSM
0.42
RV semi-amplitude (expected)
0.553 m/s
Transit-time σ at 2030
132.9 min
Max angular separation
1.13 mas
Reflected-light contrast
3.77e-9

Follow-up lanes are diagnostics, not ranking inputs. Reflected light assumes Ag = 0.30 and Lambertian quadrature.

Identifiers

system_name
Kepler-1229
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Any rendering of this world is a scientifically informed visualisation, not an image. No exoplanet has been imaged at surface resolution. Surface and cloud appearance are illustrative of a physically plausible class, not observations.