Key parameters at a glance

A radius of 2.10 Earth radii
A mass of 9.10 Earth masses
Surface gravity around 2.06 g
An orbital period of 289.864 days
Semi-major axis 0.8120 AU
Equilibrium temperature 279 K (6 °C)
Distance from Earth 634.84 light-years
Earth Similarity Index 0.845
Travel time at Voyager 1 speed 11,195,342 years

Context from the literature

Kepler-22b is an exoplanet orbiting within the habitable zone of the Sun-like star Kepler-22. It is located about 640 light-years from Earth in the constellation of Cygnus. It was discovered by NASA's Kepler Space Telescope in December 2011 and was the first known transiting planet to orbit within the habitable zone of a Sun-like star, where liquid water could exist on the planet's surface. The planet's host star Kepler-22 is too dim to be seen with the naked eye.

Excerpted from Wikipedia · full article

Kepler-22 b Planet Profile

Physical Specs

Radius

2.10 R⊕

Radius (Jupiter)

0.187 R♃

Mass

9.10 M⊕

Mass (Jupiter)

0.029 M♃

Density

5.20 g/cm³

Surface Gravity

2.06 g (Earth)

Classification

Planet Type

Sub-Neptune

ESI Score 0.845

HZ Position Habitable

Controversial No

Discovery

Year 2011

Method Transit

Facility Kepler

Telescope 0.95 m Kepler Telescope

Size rank in cohort

Rank by radius

#1818of 1978

top 91.9%

This planet

2.10R⊕

Sub-Neptune median

2.71R⊕

Nearest-size peers

TOI-5734 b 2.10 R⊕ Kepler-52 b 2.10 R⊕ Kepler-360 c 2.10 R⊕

Metric	Earth	Kepler-22 b	Jupiter
Radius (R⊕)	1.00	2.10	11.21
Mass (M⊕)	1.00	9.10	317.83
Density (g/cm³)	5.51	5.20	1.33
Surface Gravity (g)	1.00	2.06	2.53
Insolation (S⊕)	1.00	1.01	0.037

Alternative Mass Estimates

Method	Value	Interpretation
Best measured mass	9.100 M⊕	Direct mass measurement (not derived).

Star Catalogue Identifiers

TIC

TIC 158984573

Gaia DR2

Gaia DR2 2127941757262806656

Gaia DR3

Gaia DR3 2127941757262806656

System

Kepler-22

Percentile among Sub-Neptune cohort

Radius 2.100 R⊕ · percentile 7 / cohort 1978

Mass 9.100 M⊕ · percentile 66 / cohort 1978

Orbital period 289.86 d · percentile 99 / cohort 1946

Distance 194.64 pc · percentile 29 / cohort 1975

ESI 0.845 · percentile 100 / cohort 1978

Orbit & Habitability

Orbital Dynamics

Period

289.864 days

Semi-major axis

0.8120 AU

Eccentricity

0.720

Inclination

89.76 °

Year Length

A year here lasts approximately 289.86 Earth days (79.4% of a terrestrial year) on a highly eccentric trajectory at a mean orbital distance of 0.8120 AU.

Transit Fingerprint

Depth

0.050 %

Duration

7.415 h

Impact parameter b

0.768

Rp / R★

0.020319

Transit midpoint (BJD)

2,454,966.7001

Photometric dip

Transit produces a flux drop of 502 ppm lasting ≈ 7.42 h.

Extended Orbital Architecture

Planet / star radius ratio

0.020319

Semi-major axis / stellar radius

186.400

Impact parameter (b)

0.768

RV semi-amplitude (K)

1.600 m/s

Transit mid-time (BJD)

2,454,966.7001

Angular separation (arcsec)

4.17000

Eq. Temperature

279K

(6 °C)

Insolation (S⊕)

1.01

Earth = 1.00

Earth Similarity (ESI)

0.845

0 = alien, 1 = Earth-identical

Within the conservative habitable zone — liquid water is physically possible with adequate atmospheric pressure.

Discovery Paper

Primary reference

Borucki et al. 2012

Instrument

Kepler CCD Array

Publication

2012-02

Observation locale

Space

Discovery cohort

Planets confirmed in 2011 at Kepler (12 shown).

Kepler-20 d · Sub-Neptune Kepler-26 c · Sub-Neptune Kepler-19 c · Sub-Neptune Kepler-26 b · Sub-Neptune Kepler-28 c · Super-Earth Kepler-10 c · Sub-Neptune Kepler-20 f · Rocky Terrestrial Kepler-42 d · Rocky Terrestrial Kepler-16 b · Neptune-like Kepler-28 b · Super-Earth Kepler-34 b · Neptune-like Kepler-29 c · Sub-Neptune

Host System: Kepler-22

Spectral Class

G-type yellow (Sun-like)

Effective Temperature

5,596 K — cooler than the Sun (5,778 K)

Estimated Age

7.00 Gyr — older than the Sun (4.6 Gyr)

Stellar Radius

0.869 R☉

Stellar Mass

0.857 M☉

Metallicity [Fe/H]

-0.26

Extended Stellar Properties

Surface gravity (log g)

4.443 dex

Stellar density

1.458 g/cm³

Systemic radial velocity

-4.06 km/s

Rotational v·sin i

0.60 km/s

Metallicity ratio

[Fe/H]

Distance

194.64 parsec

Light-years 634.84 ly

V-band magnitude

11.75 mag

Voyager-speed travel 11,195,342 yr

Multi-band Host Photometry — 16 bands

Astrometric Data

Parallax

5.109 mas

Total Proper Motion

77.618 mas/yr

PM Right Ascension

-39.72 mas/yr

PM Declination

-66.69 mas/yr

Galactic Cartesian (pc)

x = 0.221 · y = -0.633 · z = 0.742

Equatorial (J2000)

RA 289.21721° · Dec 47.88414°

Galactic ℓ, b

79.092° · 15.792°

Ecliptic λ, β

307.663° · 68.824°

HTM-20 index

-480627441

Wikipedia → Image: Wikimedia Commons · NASA/Ames/JPL-Caltech · Public domain