Kepler-452 b
Kepler-452 b — 'Earth's older cousin': a super-Earth (1.6 Earth radii) orbiting a Sun-like star every 385 days, at almost exactly Earth's distance (1.05 AU) and receiving nearly the same sunlight Earth does — the first near-Earth-size planet found in the habitable zone of a genuine Sun-like star. Its size is measured (it transits); its mass is only size-estimated, so no density is quoted. Its statistical validation was later questioned (hence the archive's 'controversial' flag), but a 2025 reanalysis with a more rigorous method put it at under 1% false-alarm probability — high confidence — so the balance of evidence supports it. Never imaged; the appearance shown is an artist's concept.
Key facts
Science
Physical
- Radius
- 10,385 km · 1.63× wider than Earth
Orbital
- Semi-major axis
- 1.05 AU
- Eccentricity
- 0
- Inclination
- 0.00 °
- Orbital period
- 384.8 days
- Perihelion
- 1.05 AU
- Aphelion
- 1.05 AU
- Mean orbital velocity
- 29.6 km/s
Composition
- Bulk composition
- A super-Earth (1.6 Earth radii) orbiting a Sun-like star every 385 days at almost exactly Earth's distance — the first near-Earth-size planet found in the habitable zone of a genuine Sun-like star. Its size is measured (it transits); its mass is only size-estimated, so no density is quoted. Its statistical validation was questioned (Mullally 2018, Burke 2019 — hence the archive's 'controversial' flag), but a 2025 reanalysis (Robnik & Seljak, PNAS) with a more rigorous method put it below 1% false-alarm probability, among the highest-confidence candidates — so the balance of evidence supports it. Never independently mass-confirmed; never imaged (the appearance shown is an artist's concept).
- Surface appearance
- Appearance based on NASA/JPL-Caltech's artist's concept. No spacecraft has imaged this world, so its real appearance is unknown — The surface shown is an artistic representation, shown only in Vision mode; Realism shows a plain spectral colour.
Radiation & temperature
- Insolation
- 1.11 S⊕ · 1.11× the sunlight Earth receives
- Equilibrium temperature
- 265 K (-8 °C)
Discovery & history
- Method
- Transit detection
- Name
- Designated 'b' under the IAU convention that letters a star's planets 'b', 'c', 'd'... in the order they are found (the star is the unwritten 'a'); no IAU proper name has been assigned.
Validated from Kepler data in 2015 (Jenkins et al.) and celebrated worldwide as the closest analogue yet to Earth — right size, right zone, Sun-like star. Later statistical work (Mullally 2018, Burke 2019) questioned whether such a faint, long-period transit could be validated on statistics alone, and the NASA Archive retains it as 'controversial.' A 2025 reassessment (Robnik & Seljak, PNAS), however, ranked it among the highest-confidence habitable-zone candidates (false-alarm probability below 1%). It has never been independently mass-confirmed — the Sun-like host plus a 385-day orbit make the radial-velocity signal too small for current instruments — so its mass is only estimated from its size.
Images
Images from open archives · credit shown per image