Key parameters at a glance

A radius of 0.52 Earth radii
A mass of 0.09 Earth masses
Surface gravity around 0.35 g
An orbital period of 2.104 days
Semi-major axis 0.0250 AU
Equilibrium temperature 662 K (389 °C)
Distance from Earth 367.59 light-years
Earth Similarity Index 0.405
Travel time at Voyager 1 speed 6,482,522 years
Almost certainly tidally locked to its host star given the close orbit

Kepler-1308 b Planet Profile

Physical Specs

Radius

0.52 R⊕

Radius (Jupiter)

0.046 R♃

Mass

0.09 M⊕

Mass (Jupiter)

0.000 M♃

Density

3.65 g/cm³

Surface Gravity

0.35 g (Earth)

Classification

Planet Type

Rocky Terrestrial

ESI Score 0.405

HZ Position Inner

Controversial No

Discovery

Year 2016

Method Transit

Facility Kepler

Telescope 0.95 m Kepler Telescope

Size rank in cohort

Rank by radius

#559of 570

top 97.9%

This planet

0.52R⊕

Rocky Terrestrial median

1.01R⊕

Nearest-size peers

KOI-4777.01 0.51 R⊕ Kepler-1489 c 0.51 R⊕ Kepler-1994 b 0.51 R⊕

Metric	Earth	Kepler-1308 b	Jupiter
Radius (R⊕)	1.00	0.52	11.21
Mass (M⊕)	1.00	0.09	317.83
Density (g/cm³)	5.51	3.65	1.33
Surface Gravity (g)	1.00	0.35	2.53
Insolation (S⊕)	1.00	58.11	0.037

Star Catalogue Identifiers

TIC

TIC 120693011

Gaia DR2

Gaia DR2 2100018422524180864

Gaia DR3

Gaia DR3 2100018422524180864

System

Kepler-1308

Percentile among Rocky Terrestrial cohort

Radius 0.520 R⊕ · percentile 2 / cohort 570

Mass 0.093 M⊕ · percentile 2 / cohort 570

Orbital period 2.10 d · percentile 23 / cohort 567

Distance 112.71 pc · percentile 25 / cohort 566

ESI 0.405 · percentile 60 / cohort 570

Orbit & Habitability

Orbital Dynamics

Period

2.104 days

Semi-major axis

0.0250 AU

Eccentricity

0.000

Inclination

83.39 °

Year Length

A year here lasts approximately 2.10 Earth days (0.6% of a terrestrial year) on a nearly circular orbit at a mean orbital distance of 0.0250 AU.

Transit Fingerprint

Depth

0.024 %

Duration

1.103 h

Impact parameter b

0.036

Rp / R★

0.013882

Transit midpoint (BJD)

2,454,966.3148

Photometric dip

Transit produces a flux drop of 242 ppm lasting ≈ 1.10 h.

Extended Orbital Architecture

Planet / star radius ratio

0.013882

Semi-major axis / stellar radius

14.780

Impact parameter (b)

0.036

Transit mid-time (BJD)

2,454,966.3148

Angular separation (arcsec)

0.22200

Eq. Temperature

662K

(389 °C)

Insolation (S⊕)

58.11

Earth = 1.00

Earth Similarity (ESI)

0.405

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

Morton et al. 2016

Instrument

Kepler CCD Array

Publication

2016-05

Observation locale

Space

Discovery cohort

Planets confirmed in 2016 at Kepler (12 shown).

Kepler-1512 b · Rocky Terrestrial Kepler-1410 b · Super-Earth Kepler-560 b · Super-Earth Kepler-1389 b · Super-Earth Kepler-1450 b · Super-Earth Kepler-1544 b · Super-Earth Kepler-1459 b · Super-Earth Kepler-1638 b · Super-Earth Kepler-737 b · Super-Earth Kepler-1185 b · Super-Earth Kepler-1178 b · Rocky Terrestrial Kepler-1040 b · Sub-Neptune

Host System: Kepler-1308

Spectral Class

M-type red dwarf

Effective Temperature

3,468 K — cooler than the Sun (5,778 K)

Estimated Age

3.72 Gyr — younger than the Sun (4.6 Gyr)

Stellar Radius

0.340 R☉

Stellar Mass

0.350 M☉

Metallicity [Fe/H]

-0.13

Extended Stellar Properties

Surface gravity (log g)

4.920 dex

Stellar density

6.072 g/cm³

Metallicity ratio

[Fe/H]

Distance

112.71 parsec

Light-years 367.59 ly

V-band magnitude

16.40 mag

Voyager-speed travel 6,482,522 yr

Multi-band Host Photometry — 17 bands

Astrometric Data

Parallax

8.844 mas

Total Proper Motion

62.679 mas/yr

PM Right Ascension

-24.59 mas/yr

PM Declination

-57.65 mas/yr

Galactic Cartesian (pc)

x = 0.215 · y = -0.752 · z = 0.623

Equatorial (J2000)

RA 285.92875° · Dec 38.52071°

Galactic ℓ, b

69.208° · 14.282°

Ecliptic λ, β

295.879° · 60.537°

HTM-20 index

555416313