Key parameters at a glance

A radius of 1.95 Earth radii
A mass of 88.88 Earth masses
Surface gravity around 23.37 g
An orbital period of 36.445 days
Semi-major axis 0.1820 AU
Equilibrium temperature 332 K (59 °C)
Distance from Earth 1,048.73 light-years
Earth Similarity Index 0.550
Travel time at Voyager 1 speed 18,494,327 years
Almost certainly tidally locked to its host star given the close orbit

2 siblings around Kepler-52

Kepler-52 d shares its host star with 2 other confirmed planets. Side-by-side measurements below.

Planet	Type	Radius (R⊕)	Mass (M⊕)	Period (d)	Eq. T (K)	Year
Kepler-52 b	Sub-Neptune	2.10	135.00	7.877	553	2012
Kepler-52 c	Super-Earth	1.84	45.40	16.385	433	2012
Kepler-52 d this	Super-Earth	1.95	88.88	36.445	332	2014

Kepler-52 d Planet Profile

Physical Specs

Radius

1.95 R⊕

Radius (Jupiter)

0.174 R♃

Mass

88.88 M⊕

Mass (Jupiter)

0.280 M♃

Density

18.00 g/cm³

Surface Gravity

23.37 g (Earth)

Classification

Planet Type

Super-Earth

ESI Score 0.550

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

#67of 1176

top 5.6%

This planet

1.95R⊕

Super-Earth median

1.60R⊕

Nearest-size peers

K2-285 e 1.95 R⊕ Kepler-330 c 1.95 R⊕ Kepler-653 b 1.95 R⊕

Metric	Earth	Kepler-52 d	Jupiter
Radius (R⊕)	1.00	1.95	11.21
Mass (M⊕)	1.00	88.88	317.83
Density (g/cm³)	5.51	18.00	1.33
Surface Gravity (g)	1.00	23.37	2.53
Insolation (S⊕)	1.00	2.95	0.037

Alternative Mass Estimates

Method	Value	Interpretation
Best measured mass	88.878 M⊕	Direct mass measurement (not derived).

Star Catalogue Identifiers

TIC

TIC 399825554

Gaia DR2

Gaia DR2 2133589776693414016

Gaia DR3

Gaia DR3 2133589776693414016

System

Kepler-52

Percentile among Super-Earth cohort

Radius 1.950 R⊕ · percentile 94 / cohort 1176

Mass 88.878 M⊕ · percentile 99 / cohort 1176

Orbital period 36.45 d · percentile 93 / cohort 1164

Distance 321.54 pc · percentile 34 / cohort 1171

ESI 0.550 · percentile 77 / cohort 1176

Orbit & Habitability

Orbital Dynamics

Period

36.445 days

Semi-major axis

0.1820 AU

Eccentricity

0.000

Inclination

89.98 °

Year Length

A year here lasts approximately 36.45 Earth days (10.0% of a terrestrial year) on a nearly circular orbit at a mean orbital distance of 0.1820 AU.

Transit Fingerprint

Depth

0.116 %

Duration

4.153 h

Impact parameter b

0.760

Rp / R★

0.030505

Transit midpoint (BJD)

2,454,984.6012

Photometric dip

Transit produces a flux drop of 1,156 ppm lasting ≈ 4.15 h.

Extended Orbital Architecture

Planet / star radius ratio

0.030505

Semi-major axis / stellar radius

71.500

Impact parameter (b)

0.760

Transit mid-time (BJD)

2,454,984.6012

Angular separation (arcsec)

0.56600

Eq. Temperature

332K

(59 °C)

Insolation (S⊕)

2.95

Earth = 1.00

Earth Similarity (ESI)

0.550

0 = alien, 1 = Earth-identical

Inside the inner HZ boundary (too hot for liquid water) — liquid water is physically possible with adequate atmospheric pressure. Close-orbiting tidally-locked around a cool host.

Detection Signatures

Transit photometry

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

Transit timing variations

Gravitational interactions from neighbours have been detected.

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-52

Spectral Class

M-type red dwarf

Effective Temperature

4,263 K — cooler than the Sun (5,778 K)

Estimated Age

1.01 Gyr — younger than the Sun (4.6 Gyr)

Stellar Radius

0.556 R☉

Stellar Mass

0.577 M☉

Metallicity [Fe/H]

0.00

Extended Stellar Properties

Surface gravity (log g)

4.729 dex

Stellar density

3.440 g/cm³

Metallicity ratio

[Fe/H]

Distance

321.54 parsec

Light-years 1,048.73 ly

V-band magnitude

15.51 mag

Voyager-speed travel 18,494,327 yr

Multi-band Host Photometry — 16 bands

Astrometric Data

Parallax

3.081 mas

Total Proper Motion

4.207 mas/yr

PM Right Ascension

-3.98 mas/yr

PM Declination

1.38 mas/yr

Galactic Cartesian (pc)

x = 0.185 · y = -0.616 · z = 0.766

Equatorial (J2000)

RA 286.73802° · Dec 49.97574°

Galactic ℓ, b

80.478° · 18.087°

Ecliptic λ, β

305.415° · 71.362°

HTM-20 index

364710180