Key parameters at a glance

A radius of 1.56 Earth radii
A mass of 3.05 Earth masses
Surface gravity around 1.25 g
An orbital period of 5.924 days
Semi-major axis 0.0590 AU
Equilibrium temperature 531 K (258 °C)
Distance from Earth 1,776.14 light-years
Earth Similarity Index 0.555
Travel time at Voyager 1 speed 31,322,248 years
Almost certainly tidally locked to its host star given the close orbit

1 sibling around Kepler-309

Kepler-309 b shares its host star with 1 other confirmed planet. Side-by-side measurements below.

Planet	Type	Radius (R⊕)	Mass (M⊕)	Period (d)	Eq. T (K)	Year
Kepler-309 b this	Super-Earth	1.56	3.05	5.924	531	2014
Kepler-309 c	Sub-Neptune	2.51	6.85	105.356	204	2014

Kepler-309 b Planet Profile

Physical Specs

Radius

1.56 R⊕

Radius (Jupiter)

0.139 R♃

Mass

3.05 M⊕

Mass (Jupiter)

0.010 M♃

Density

4.41 g/cm³

Surface Gravity

1.25 g (Earth)

Classification

Planet Type

Super-Earth

ESI Score 0.555

HZ Position Inner

Controversial No

Discovery

Year 2014

Method Transit

Facility Kepler

Telescope 0.95 m Kepler Telescope

Size rank in cohort

Rank by radius

#636of 1176

top 54.0%

This planet

1.56R⊕

Super-Earth median

1.60R⊕

Nearest-size peers

Kepler-338 e 1.56 R⊕ Kepler-402 c 1.56 R⊕ Kepler-49 e 1.56 R⊕

Metric	Earth	Kepler-309 b	Jupiter
Radius (R⊕)	1.00	1.56	11.21
Mass (M⊕)	1.00	3.05	317.83
Density (g/cm³)	5.51	4.41	1.33
Surface Gravity (g)	1.00	1.25	2.53
Insolation (S⊕)	1.00	99.49	0.037

Star Catalogue Identifiers

TIC

TIC 273373488

Gaia DR2

Gaia DR2 2086315415269037696

Gaia DR3

Gaia DR3 2086315415269037696

System

Kepler-309

Percentile among Super-Earth cohort

Radius 1.560 R⊕ · percentile 45 / cohort 1176

Mass 3.050 M⊕ · percentile 41 / cohort 1176

Orbital period 5.92 d · percentile 47 / cohort 1164

Distance 544.57 pc · percentile 50 / cohort 1171

ESI 0.555 · percentile 77 / cohort 1176

Orbit & Habitability

Orbital Dynamics

Period

5.924 days

Semi-major axis

0.0590 AU

Eccentricity

0.000

Inclination

89.85 °

Year Length

A year here lasts approximately 5.92 Earth days (1.6% of a terrestrial year) on a nearly circular orbit at a mean orbital distance of 0.0590 AU.

Transit Fingerprint

Depth

0.041 %

Duration

2.787 h

Impact parameter b

0.810

Rp / R★

0.018295

Transit midpoint (BJD)

2,454,967.6824

Photometric dip

Transit produces a flux drop of 407 ppm lasting ≈ 2.79 h.

Extended Orbital Architecture

Planet / star radius ratio

0.018295

Semi-major axis / stellar radius

17.510

Impact parameter (b)

0.810

Transit mid-time (BJD)

2,454,967.6824

Angular separation (arcsec)

0.10800

Eq. Temperature

531K

(258 °C)

Insolation (S⊕)

99.49

Earth = 1.00

Earth Similarity (ESI)

0.555

0 = alien, 1 = Earth-identical

Inside the inner HZ boundary (too hot for liquid water) — the surface is too hot to retain surface water. Close-orbiting tidally-locked around a cool host.

Discovery Paper

Primary reference

Rowe et al. 2014

Instrument

Kepler CCD Array

Publication

2014-03

Observation locale

Space

Discovery cohort

Planets confirmed in 2014 at Kepler (12 shown).

Kepler-186 e · Super-Earth Kepler-395 c · Super-Earth Kepler-220 e · Super-Earth Kepler-249 d · Super-Earth Kepler-296 f · Super-Earth Kepler-367 c · Rocky Terrestrial Kepler-296 e · Super-Earth Kepler-155 c · Sub-Neptune Kepler-138 d · Super-Earth Kepler-333 c · Rocky Terrestrial Kepler-331 d · Super-Earth Kepler-267 d · Sub-Neptune

Host System: Kepler-309

Spectral Class

M-type red dwarf

Effective Temperature

4,713 K — cooler than the Sun (5,778 K)

Estimated Age

3.02 Gyr — younger than the Sun (4.6 Gyr)

Stellar Radius

0.721 R☉

Stellar Mass

0.816 M☉

Metallicity [Fe/H]

0.27

Extended Stellar Properties

Surface gravity (log g)

4.612 dex

Stellar density

1.940 g/cm³

Metallicity ratio

[Fe/H]

Distance

544.57 parsec

Light-years 1,776.14 ly

V-band magnitude

15.42 mag

Voyager-speed travel 31,322,248 yr

Multi-band Host Photometry — 16 bands

Astrometric Data

Parallax

1.808 mas

Total Proper Motion

35.063 mas/yr

PM Right Ascension

3.70 mas/yr

PM Declination

34.87 mas/yr

Galactic Cartesian (pc)

x = 0.315 · y = -0.605 · z = 0.731

Equatorial (J2000)

RA 297.50989° · Dec 46.96141°

Galactic ℓ, b

80.771° · 10.349°

Ecliptic λ, β

319.983° · 65.695°

HTM-20 index

1124262296