Key parameters at a glance

A radius of 2.36 Earth radii
A mass of 8.03 Earth masses
Surface gravity around 1.45 g
An orbital period of 5.399 days
Semi-major axis 0.0614 AU
Equilibrium temperature 1,275 K (1002 °C)
Distance from Earth 470.21 light-years
Earth Similarity Index 0.202
Travel time at Voyager 1 speed 8,292,083 years

3 siblings around Kepler-68

Kepler-68 b shares its host star with 3 other confirmed planets. Side-by-side measurements below.

Planet	Type	Radius (R⊕)	Mass (M⊕)	Period (d)	Eq. T (K)	Year
Kepler-68 b this	Sub-Neptune	2.36	8.03	5.399	1,275	2013
Kepler-68 c	Rocky Terrestrial	0.98	1.30	9.605	1,052	2013
Kepler-68 d	Gas Giant	13.90	267.00	632.620	—	2013
Kepler-68 e	Gas Giant	11.20	86.45	3,455.000	—	2023

Kepler-68 b Planet Profile

Physical Specs

Radius

2.36 R⊕

Radius (Jupiter)

0.210 R♃

Mass

8.03 M⊕

Mass (Jupiter)

0.025 M♃

Density

3.37 g/cm³

Surface Gravity

1.45 g (Earth)

Classification

Planet Type

Sub-Neptune

ESI Score 0.202

HZ Position Inner

Controversial No

Discovery

Year 2013

Method Transit

Facility Kepler

Telescope 0.95 m Kepler Telescope

Size rank in cohort

Rank by radius

#1410of 1978

top 71.2%

This planet

2.36R⊕

Sub-Neptune median

2.71R⊕

Nearest-size peers

Kepler-1806 b 2.36 R⊕ Kepler-10 c 2.36 R⊕ K2-366 b 2.36 R⊕

Metric	Earth	Kepler-68 b	Jupiter
Radius (R⊕)	1.00	2.36	11.21
Mass (M⊕)	1.00	8.03	317.83
Density (g/cm³)	5.51	3.37	1.33
Surface Gravity (g)	1.00	1.45	2.53
Insolation (S⊕)	1.00	441.00	0.037

Alternative Mass Estimates

Method	Value	Interpretation
Best measured mass	8.030 M⊕	Direct mass measurement (not derived).
Minimum mass (M sin i)	8.441 M⊕	Lower bound from radial-velocity fitting.

Star Catalogue Identifiers

TIC

TIC 417676622

Gaia DR2

Gaia DR2 2129550445852902656

Gaia DR3

Gaia DR3 2129550445852902656

System

Kepler-68

Percentile among Sub-Neptune cohort

Radius 2.357 R⊕ · percentile 29 / cohort 1978

Mass 8.030 M⊕ · percentile 54 / cohort 1978

Orbital period 5.40 d · percentile 14 / cohort 1946

Distance 144.17 pc · percentile 25 / cohort 1975

ESI 0.202 · percentile 7 / cohort 1978

Orbit & Habitability

Orbital Dynamics

Period

5.399 days

Semi-major axis

0.0614 AU

Eccentricity

0.090

Inclination

87.23 °

Year Length

A year here lasts approximately 5.40 Earth days (1.5% of a terrestrial year) on a nearly circular orbit at a mean orbital distance of 0.0614 AU.

Transit Fingerprint

Depth

0.035 %

Duration

3.434 h

Impact parameter b

0.480

Rp / R★

0.018690

Transit midpoint (BJD)

2,455,006.8588

Photometric dip

Transit produces a flux drop of 346 ppm lasting ≈ 3.43 h.

Extended Orbital Architecture

Planet / star radius ratio

0.018690

Semi-major axis / stellar radius

12.223

Impact parameter (b)

0.480

RV semi-amplitude (K)

2.830 m/s

Transit mid-time (BJD)

2,455,006.8588

Long. of periastron (ω)

0.00°

Angular separation (arcsec)

0.42600

Eq. Temperature

1,275K

(1002 °C)

Insolation (S⊕)

441.00

Earth = 1.00

Earth Similarity (ESI)

0.202

0 = alien, 1 = Earth-identical

Inside the inner HZ boundary (too hot for liquid water) — the dayside is scorched.

Detection Signatures

Transit photometry

A transit dip has been observed from at least one telescope.

Radial velocity

Stellar wobble has been measured spectroscopically.

Discovery Paper

Primary reference

Gilliland et al. 2013

Instrument

Kepler CCD Array

Publication

2013-03

Observation locale

Space

Discovery cohort

Planets confirmed in 2013 at Kepler (12 shown).

Kepler-69 c · Super-Earth Kepler-61 b · Sub-Neptune Kepler-62 e · Super-Earth KOI-351 f · Sub-Neptune Kepler-62 f · Super-Earth KOI-351 e · Sub-Neptune Kepler-1704 b · Gas Giant Kepler-37 d · Sub-Neptune Kepler-282 e · Sub-Neptune KOI-351 h · Gas Giant KOI-351 d · Sub-Neptune Kepler-114 c · Super-Earth

Host System: Kepler-68

Spectral Class

G-type yellow (Sun-like)

Effective Temperature

5,847 K — hotter than the Sun (5,778 K)

Estimated Age

6.84 Gyr — older than the Sun (4.6 Gyr)

Stellar Radius

1.256 R☉

Stellar Mass

1.057 M☉

Metallicity [Fe/H]

0.11

Extended Stellar Properties

Surface gravity (log g)

4.281 dex

Stellar density

0.790 g/cm³

Systemic radial velocity

-20.90 km/s

Rotational v·sin i

0.50 km/s

Metallicity ratio

[Fe/H]

Distance

144.17 parsec

Light-years 470.21 ly

V-band magnitude

10.08 mag

Voyager-speed travel 8,292,083 yr

Multi-band Host Photometry — 16 bands

Astrometric Data

Parallax

6.908 mas

Total Proper Motion

12.750 mas/yr

PM Right Ascension

-7.33 mas/yr

PM Declination

-10.43 mas/yr

Galactic Cartesian (pc)

x = 0.235 · y = -0.612 · z = 0.755

Equatorial (J2000)

RA 291.03231° · Dec 49.04021°

Galactic ℓ, b

80.691° · 15.154°

Ecliptic λ, β

312.030° · 69.429°

HTM-20 index

861394382

Observation Record

RV measurements

Transmission spectra

Archive notes