Key parameters at a glance

A radius of 2.03 Earth radii
A mass of 2.00 Earth masses
Surface gravity around 0.49 g
An orbital period of 39.792 days
Semi-major axis 0.2109 AU
Equilibrium temperature 499 K (226 °C)
Distance from Earth 208.48 light-years
Earth Similarity Index 0.471
Travel time at Voyager 1 speed 3,676,566 years

Context from the literature

Kepler-37d is an exoplanet discovered by the Kepler space telescope in February 2013. It is located 209 light years away, in the constellation Lyra. With an orbital period of 39.8 days, it is the largest of the three known planets orbiting its parent star Kepler-37.

Excerpted from Wikipedia · full article

3 siblings around Kepler-37

Kepler-37 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-37 b	Rocky Terrestrial	0.31	0.79	13.367	718	2013
Kepler-37 c	Rocky Terrestrial	0.76	1.30	21.302	615	2013
Kepler-37 d this	Sub-Neptune	2.03	2.00	39.792	499	2013
Kepler-37 e	Rocky Terrestrial	0.37	8.10	51.196	401	2014

Kepler-37 d Planet Profile

Physical Specs

Radius

2.03 R⊕

Radius (Jupiter)

0.181 R♃

Mass

2.00 M⊕

Mass (Jupiter)

0.006 M♃

Density

1.30 g/cm³

Surface Gravity

0.49 g (Earth)

Classification

Planet Type

Sub-Neptune

ESI Score 0.471

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

#1915of 1978

top 96.8%

This planet

2.03R⊕

Sub-Neptune median

2.71R⊕

Nearest-size peers

K2-117 b 2.03 R⊕ Kepler-195 b 2.03 R⊕ GJ 2030 b 2.03 R⊕

Metric	Earth	Kepler-37 d	Jupiter
Radius (R⊕)	1.00	2.03	11.21
Mass (M⊕)	1.00	2.00	317.83
Density (g/cm³)	5.51	1.30	1.33
Surface Gravity (g)	1.00	0.49	2.53
Insolation (S⊕)	1.00	10.39	0.037

Alternative Mass Estimates

Method	Value	Interpretation
Best measured mass	2.000 M⊕	Direct mass measurement (not derived).

Star Catalogue Identifiers

TIC

TIC 164652245

Gaia DR2

Gaia DR2 2106674071344722688

Gaia DR3

Gaia DR3 2106674071344722688

System

Kepler-37

Percentile among Sub-Neptune cohort

Radius 2.030 R⊕ · percentile 3 / cohort 1978

Mass 2.000 M⊕ · percentile 0 / cohort 1978

Orbital period 39.79 d · percentile 80 / cohort 1946

Distance 63.92 pc · percentile 14 / cohort 1975

ESI 0.471 · percentile 66 / cohort 1978

Orbit & Habitability

Orbital Dynamics

Period

39.792 days

Semi-major axis

0.2109 AU

Eccentricity

0.100

Inclination

89.34 °

Year Length

A year here lasts approximately 39.79 Earth days (10.9% of a terrestrial year) on a mildly elliptical path at a mean orbital distance of 0.2109 AU.

Transit Fingerprint

Depth

0.060 %

Duration

4.447 h

Impact parameter b

0.535

Rp / R★

0.023201

Transit midpoint (BJD)

2,455,008.2498

Photometric dip

Transit produces a flux drop of 604 ppm lasting ≈ 4.45 h.

Extended Orbital Architecture

Planet / star radius ratio

0.023201

Semi-major axis / stellar radius

69.576

Impact parameter (b)

0.535

RV semi-amplitude (K)

0.440 m/s

Transit mid-time (BJD)

2,455,008.2498

Angular separation (arcsec)

3.30000

Eq. Temperature

499K

(226 °C)

Insolation (S⊕)

10.39

Earth = 1.00

Earth Similarity (ESI)

0.471

0 = alien, 1 = Earth-identical

Inside the inner HZ boundary (too hot for liquid water) — the surface is too hot to retain surface water.

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

Barclay et al. 2013

Instrument

Kepler CCD Array

Publication

2013-02

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-282 e · Sub-Neptune KOI-351 h · Gas Giant KOI-351 d · Sub-Neptune Kepler-114 c · Super-Earth Kepler-396 b · Sub-Neptune

Host System: Kepler-37

Spectral Class

G-type yellow (Sun-like)

Effective Temperature

5,357 K — cooler than the Sun (5,778 K)

Estimated Age

7.60 Gyr — older than the Sun (4.6 Gyr)

Stellar Radius

0.789 R☉

Stellar Mass

0.790 M☉

Metallicity [Fe/H]

-0.36

Extended Stellar Properties

Surface gravity (log g)

4.567 dex

Stellar density

2.460 g/cm³

Systemic radial velocity

-30.10 km/s

Rotational v·sin i

1.10 km/s

Metallicity ratio

[Fe/H]

Distance

63.92 parsec

Light-years 208.48 ly

V-band magnitude

9.77 mag

Voyager-speed travel 3,676,566 yr

Multi-band Host Photometry — 14 bands

Astrometric Data

Parallax

15.616 mas

Total Proper Motion

77.677 mas/yr

PM Right Ascension

-60.52 mas/yr

PM Declination

48.69 mas/yr

Galactic Cartesian (pc)

x = 0.173 · y = -0.692 · z = 0.701

Equatorial (J2000)

RA 284.05925° · Dec 44.51837°

Galactic ℓ, b

74.437° · 17.844°

Ecliptic λ, β

295.961° · 66.695°

HTM-20 index

842412176

Observation Record

RV measurements

Transmission spectra

Archive notes

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