Key parameters at a glance

A radius of 2.09 Earth radii
A mass of 5.02 Earth masses
Surface gravity around 1.15 g
An orbital period of 19.850 days
Semi-major axis 0.1180 AU
Equilibrium temperature 403 K (130 °C)
Distance from Earth 544.68 light-years
Earth Similarity Index 0.584
Travel time at Voyager 1 speed 9,605,440 years
Almost certainly tidally locked to its host star given the close orbit

Context from the literature

Kepler-296d is an exoplanet orbiting the M-dwarf star Kepler-296, located in the constellation Draco. It was discovered in 2014 by the Kepler space telescope using the transit method.

Excerpted from Wikipedia · full article

4 siblings around Kepler-296

Kepler-296 d shares its host star with 4 other confirmed planets. Side-by-side measurements below.

Planet	Type	Radius (R⊕)	Mass (M⊕)	Period (d)	Eq. T (K)	Year
Kepler-296 c	Sub-Neptune	2.00	4.66	5.842	606	2014
Kepler-296 b	Super-Earth	1.61	3.22	10.864	495	2014
Kepler-296 d this	Sub-Neptune	2.09	5.02	19.850	403	2014
Kepler-296 e	Super-Earth	1.53	2.96	34.142	337	2014
Kepler-296 f	Super-Earth	1.80	3.89	63.336	274	2014

Kepler-296 d Planet Profile

Physical Specs

Radius

2.09 R⊕

Radius (Jupiter)

0.186 R♃

Mass

5.02 M⊕

Mass (Jupiter)

0.016 M♃

Density

1.90 g/cm³

Surface Gravity

1.15 g (Earth)

Classification

Planet Type

Sub-Neptune

ESI Score 0.584

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

#1832of 1978

top 92.6%

This planet

2.09R⊕

Sub-Neptune median

2.71R⊕

Nearest-size peers

Kepler-317 b 2.09 R⊕ Kepler-151 c 2.09 R⊕ Kepler-372 c 2.09 R⊕

Metric	Earth	Kepler-296 d	Jupiter
Radius (R⊕)	1.00	2.09	11.21
Mass (M⊕)	1.00	5.02	317.83
Density (g/cm³)	5.51	1.90	1.33
Surface Gravity (g)	1.00	1.15	2.53
Insolation (S⊕)	1.00	2.90	0.037

Star Catalogue Identifiers

TIC

TIC 243271945

Gaia DR2

Gaia DR2 2132069633148965888

Gaia DR3

Gaia DR3 2132069633148965888

System

Kepler-296

Percentile among Sub-Neptune cohort

Radius 2.090 R⊕ · percentile 7 / cohort 1978

Mass 5.020 M⊕ · percentile 8 / cohort 1978

Orbital period 19.85 d · percentile 62 / cohort 1946

Distance 167.00 pc · percentile 26 / cohort 1975

ESI 0.584 · percentile 81 / cohort 1978

Orbit & Habitability

Orbital Dynamics

Period

19.850 days

Semi-major axis

0.1180 AU

Eccentricity

0.330

Inclination

89.77 °

Year Length

A year here lasts approximately 19.85 Earth days (5.4% of a terrestrial year) on a highly eccentric trajectory at a mean orbital distance of 0.1180 AU.

Transit Fingerprint

Depth

0.161 %

Duration

2.841 h

Impact parameter b

0.260

Rp / R★

0.039800

Transit midpoint (BJD)

2,454,966.6496

Photometric dip

Transit produces a flux drop of 1,608 ppm lasting ≈ 2.84 h.

Extended Orbital Architecture

Planet / star radius ratio

0.039800

Semi-major axis / stellar radius

53.100

Impact parameter (b)

0.260

Transit mid-time (BJD)

2,454,966.6496

Angular separation (arcsec)

0.70700

Eq. Temperature

403K

(130 °C)

Insolation (S⊕)

2.90

Earth = 1.00

Earth Similarity (ESI)

0.584

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-296

Spectral Class

M-type red dwarf

Effective Temperature

3,740 K — cooler than the Sun (5,778 K)

Estimated Age

4.20 Gyr — younger than the Sun (4.6 Gyr)

Stellar Radius

0.480 R☉

Stellar Mass

0.498 M☉

Metallicity [Fe/H]

-0.08

Extended Stellar Properties

Surface gravity (log g)

4.774 dex

Stellar density

6.400 g/cm³

Metallicity ratio

[Fe/H]

Distance

167.00 parsec

Light-years 544.68 ly

V-band magnitude

16.36 mag

Voyager-speed travel 9,605,440 yr

Multi-band Host Photometry — 16 bands

Astrometric Data

Total Proper Motion

11.640 mas/yr

PM Right Ascension

1.84 mas/yr

PM Declination

-11.49 mas/yr

Galactic Cartesian (pc)

x = 0.185 · y = -0.623 · z = 0.760

Equatorial (J2000)

RA 286.54003° · Dec 49.43726°

Galactic ℓ, b

79.901° · 18.014°

Ecliptic λ, β

304.458° · 70.904°

HTM-20 index

339564586

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