Key parameters at a glance

A radius of 2.16 Earth radii
A mass of 5.31 Earth masses
Surface gravity around 1.14 g
An orbital period of 3.547 days
Semi-major axis 0.0470 AU
Equilibrium temperature 1,212 K (939 °C)
Distance from Earth 5,826.71 light-years
Earth Similarity Index 0.214
Travel time at Voyager 1 speed 102,754,055 years

1 sibling around Kepler-291

Kepler-291 b shares its host star with 1 other confirmed planet. Side-by-side measurements below.

Planet	Type	Radius (R⊕)	Mass (M⊕)	Period (d)	Eq. T (K)	Year
Kepler-291 b this	Sub-Neptune	2.16	5.31	3.547	1,212	2014
Kepler-291 c	Super-Earth	1.88	4.19	5.701	1,035	2014

Kepler-291 b Planet Profile

Physical Specs

Radius

2.16 R⊕

Radius (Jupiter)

0.193 R♃

Mass

5.31 M⊕

Mass (Jupiter)

0.017 M♃

Density

2.90 g/cm³

Surface Gravity

1.14 g (Earth)

Classification

Planet Type

Sub-Neptune

ESI Score 0.214

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

#1731of 1978

top 87.5%

This planet

2.16R⊕

Sub-Neptune median

2.71R⊕

Nearest-size peers

Kepler-142 d 2.16 R⊕ Kepler-308 c 2.16 R⊕ Kepler-1621 b 2.16 R⊕

Metric	Earth	Kepler-291 b	Jupiter
Radius (R⊕)	1.00	2.16	11.21
Mass (M⊕)	1.00	5.31	317.83
Density (g/cm³)	5.51	2.90	1.33
Surface Gravity (g)	1.00	1.14	2.53
Insolation (S⊕)	1.00	627.37	0.037

Star Catalogue Identifiers

TIC

TIC 158631683

Gaia DR2

Gaia DR2 2102509125599126144

Gaia DR3

Gaia DR3 2102509125599126144

System

Kepler-291

Percentile among Sub-Neptune cohort

Radius 2.160 R⊕ · percentile 12 / cohort 1978

Mass 5.310 M⊕ · percentile 13 / cohort 1978

Orbital period 3.55 d · percentile 7 / cohort 1946

Distance 1,786.48 pc · percentile 96 / cohort 1975

ESI 0.214 · percentile 9 / cohort 1978

Orbit & Habitability

Orbital Dynamics

Period

3.547 days

Semi-major axis

0.0470 AU

Eccentricity

0.000

Inclination

86.20 °

Year Length

A year here lasts approximately 3.55 Earth days (1.0% of a terrestrial year) on a nearly circular orbit at a mean orbital distance of 0.0470 AU.

Transit Fingerprint

Depth

0.044 %

Duration

2.266 h

Impact parameter b

0.330

Rp / R★

0.020142

Transit midpoint (BJD)

2,454,967.9011

Photometric dip

Transit produces a flux drop of 443 ppm lasting ≈ 2.27 h.

Extended Orbital Architecture

Planet / star radius ratio

0.020142

Semi-major axis / stellar radius

11.910

Impact parameter (b)

0.330

Transit mid-time (BJD)

2,454,967.9011

Angular separation (arcsec)

0.02630

Eq. Temperature

1,212K

(939 °C)

Insolation (S⊕)

627.37

Earth = 1.00

Earth Similarity (ESI)

0.214

0 = alien, 1 = Earth-identical

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

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-291

Spectral Class

F-type yellow-white

Effective Temperature

6,002 K — hotter than the Sun (5,778 K)

Estimated Age

7.76 Gyr — older than the Sun (4.6 Gyr)

Stellar Radius

1.016 R☉

Stellar Mass

1.023 M☉

Metallicity [Fe/H]

0.23

Extended Stellar Properties

Surface gravity (log g)

4.472 dex

Stellar density

0.650 g/cm³

Metallicity ratio

[Fe/H]

Distance

1,786.48 parsec

Light-years 5,826.71 ly

V-band magnitude

16.22 mag

Voyager-speed travel 102,754,055 yr

Multi-band Host Photometry — 16 bands

Astrometric Data

Parallax

0.531 mas

Total Proper Motion

7.996 mas/yr

PM Right Ascension

-3.33 mas/yr

PM Declination

-7.27 mas/yr

Galactic Cartesian (pc)

x = 0.227 · y = -0.702 · z = 0.675

Equatorial (J2000)

RA 287.91630° · Dec 42.43727°

Galactic ℓ, b

73.537° · 14.465°

Ecliptic λ, β

301.129° · 63.953°

HTM-20 index

-1941729273