Key parameters at a glance

A radius of 1.07 Earth radii
A mass of 1.24 Earth masses
Surface gravity around 1.08 g
An orbital period of 3.544 days
Semi-major axis 0.0390 AU
Equilibrium temperature 652 K (379 °C)
Distance from Earth 1,093.62 light-years
Earth Similarity Index 0.499
Travel time at Voyager 1 speed 19,286,056 years
Almost certainly tidally locked to its host star given the close orbit

3 siblings around Kepler-26

Kepler-26 d 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-26 d this	Rocky Terrestrial	1.07	1.24	3.544	652	2014
Kepler-26 b	Sub-Neptune	2.78	5.12	12.280	431	2011
Kepler-26 c	Sub-Neptune	2.72	6.20	17.256	385	2011
Kepler-26 e	Sub-Neptune	2.41	6.39	46.828	276	2014

Kepler-26 d Planet Profile

Physical Specs

Radius

1.07 R⊕

Radius (Jupiter)

0.095 R♃

Mass

1.24 M⊕

Mass (Jupiter)

0.004 M♃

Density

5.56 g/cm³

Surface Gravity

1.08 g (Earth)

Classification

Planet Type

Rocky Terrestrial

ESI Score 0.499

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

#262of 570

top 45.8%

This planet

1.07R⊕

Rocky Terrestrial median

1.01R⊕

Nearest-size peers

Kepler-376 b 1.07 R⊕ Kepler-186 b 1.07 R⊕ Kepler-1570 b 1.07 R⊕

Metric	Earth	Kepler-26 d	Jupiter
Radius (R⊕)	1.00	1.07	11.21
Mass (M⊕)	1.00	1.24	317.83
Density (g/cm³)	5.51	5.56	1.33
Surface Gravity (g)	1.00	1.08	2.53
Insolation (S⊕)	1.00	31.79	0.037

Star Catalogue Identifiers

TIC

TIC 164833065

Gaia DR2

Gaia DR2 2107317358665730688

Gaia DR3

Gaia DR3 2107317358665730688

System

Kepler-26

Percentile among Rocky Terrestrial cohort

Radius 1.070 R⊕ · percentile 53 / cohort 570

Mass 1.240 M⊕ · percentile 48 / cohort 570

Orbital period 3.54 d · percentile 39 / cohort 567

Distance 335.31 pc · percentile 45 / cohort 566

ESI 0.499 · percentile 70 / cohort 570

Orbit & Habitability

Orbital Dynamics

Period

3.544 days

Semi-major axis

0.0390 AU

Eccentricity

0.000

Inclination

89.91 °

Year Length

A year here lasts approximately 3.54 Earth days (1.0% of a terrestrial year) on a nearly circular orbit at a mean orbital distance of 0.0390 AU.

Transit Fingerprint

Depth

0.051 %

Duration

2.012 h

Impact parameter b

0.310

Rp / R★

0.020559

Transit midpoint (BJD)

2,454,969.2590

Photometric dip

Transit produces a flux drop of 507 ppm lasting ≈ 2.01 h.

Extended Orbital Architecture

Planet / star radius ratio

0.020559

Semi-major axis / stellar radius

14.476

Impact parameter (b)

0.310

Transit mid-time (BJD)

2,454,969.2590

Angular separation (arcsec)

0.11600

Eq. Temperature

652K

(379 °C)

Insolation (S⊕)

31.79

Earth = 1.00

Earth Similarity (ESI)

0.499

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-26

Spectral Class

M-type red dwarf

Effective Temperature

4,486 K — cooler than the Sun (5,778 K)

Estimated Age

2.95 Gyr — younger than the Sun (4.6 Gyr)

Stellar Radius

0.571 R☉

Stellar Mass

0.593 M☉

Metallicity [Fe/H]

-0.21

Extended Stellar Properties

Surface gravity (log g)

4.733 dex

Stellar density

5.983 g/cm³

Rotational v·sin i

1.90 km/s

Metallicity ratio

[M/H]

Distance

335.31 parsec

Light-years 1,093.62 ly

V-band magnitude

15.85 mag

Voyager-speed travel 19,286,056 yr

Multi-band Host Photometry — 16 bands

Astrometric Data

Parallax

2.954 mas

Total Proper Motion

16.909 mas/yr

PM Right Ascension

9.54 mas/yr

PM Declination

-13.96 mas/yr

Galactic Cartesian (pc)

x = 0.177 · y = -0.664 · z = 0.726

Equatorial (J2000)

RA 284.94106° · Dec 46.56645°

Galactic ℓ, b

76.680° · 17.993°

Ecliptic λ, β

298.934° · 68.510°

HTM-20 index

-1382944939