Key parameters at a glance

A radius of 4.57 Earth radii
A mass of 47.80 Earth masses
Surface gravity around 2.28 g
An orbital period of 31.562 days
Semi-major axis 0.1974 AU
Equilibrium temperature 651 K (378 °C)
Distance from Earth 606.24 light-years
Earth Similarity Index 0.328
Travel time at Voyager 1 speed 10,691,085 years

1 sibling around Kepler-1656

Kepler-1656 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-1656 b this	Neptune-like	4.57	47.80	31.562	651	2018
Kepler-1656 c	Gas Giant	14.00	126.40	1,919.000	—	2022

Kepler-1656 b Planet Profile

Physical Specs

Radius

4.57 R⊕

Radius (Jupiter)

0.408 R♃

Mass

47.80 M⊕

Mass (Jupiter)

0.150 M♃

Density

2.13 g/cm³

Surface Gravity

2.28 g (Earth)

Classification

Planet Type

Neptune-like

ESI Score 0.328

HZ Position Inner

Controversial No

Discovery

Year 2018

Method Transit

Facility Kepler

Telescope 0.95 m Kepler Telescope

Size rank in cohort

Rank by radius

#452of 574

top 78.6%

This planet

4.57R⊕

Neptune-like median

6.39R⊕

Nearest-size peers

GJ 3470 b 4.57 R⊕ Kepler-740 b 4.57 R⊕ K2-405 b 4.57 R⊕

Metric	Earth	Kepler-1656 b	Jupiter
Radius (R⊕)	1.00	4.57	11.21
Mass (M⊕)	1.00	47.80	317.83
Density (g/cm³)	5.51	2.13	1.33
Surface Gravity (g)	1.00	2.28	2.53
Insolation (S⊕)	1.00	24.60	0.037

Alternative Mass Estimates

Method	Value	Interpretation
Best measured mass	47.800 M⊕	Direct mass measurement (not derived).
Minimum mass (M sin i)	47.800 M⊕	Lower bound from radial-velocity fitting.

Star Catalogue Identifiers

TIC

TIC 120255950

Gaia DR2

Gaia DR2 2103392720630278656

Gaia DR3

Gaia DR3 2103392720630278656

System

Kepler-1656

Percentile among Neptune-like cohort

Radius 4.574 R⊕ · percentile 21 / cohort 574

Mass 47.800 M⊕ · percentile 69 / cohort 574

Orbital period 31.56 d · percentile 61 / cohort 524

Distance 185.88 pc · percentile 37 / cohort 572

ESI 0.328 · percentile 58 / cohort 574

Orbit & Habitability

Orbital Dynamics

Period

31.562 days

Semi-major axis

0.1974 AU

Eccentricity

0.838

Inclination

89.31 °

Year Length

A year here lasts approximately 31.56 Earth days (8.6% of a terrestrial year) on a highly eccentric trajectory at a mean orbital distance of 0.1974 AU.

Transit Fingerprint

Depth

0.213 %

Duration

2.124 h

Impact parameter b

0.083

Rp / R★

0.041908

Transit midpoint (BJD)

2,455,011.4700

Photometric dip

Transit produces a flux drop of 2,125 ppm lasting ≈ 2.12 h.

Extended Orbital Architecture

Planet / star radius ratio

0.041908

Semi-major axis / stellar radius

118.027

Impact parameter (b)

0.083

RV semi-amplitude (K)

17.100 m/s

Transit mid-time (BJD)

2,455,011.4700

Long. of periastron (ω)

52.80°

Angular separation (arcsec)

1.06000

Eq. Temperature

651K

(378 °C)

Insolation (S⊕)

24.60

Earth = 1.00

Earth Similarity (ESI)

0.328

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.

Radial velocity

Stellar wobble has been measured spectroscopically.

Discovery Paper

Primary reference

Brady et al. 2018

Instrument

Kepler CCD Array

Publication

2018-10

Observation locale

Space

Discovery cohort

Planets confirmed in 2018 at Kepler (6 shown).

Kepler-411 d · Sub-Neptune KOI-3680 b · Gas Giant Kepler-411 e · Sub-Neptune Kepler-1654 b · Neptune-like Kepler-1655 b · Sub-Neptune Kepler-730 c · Super-Earth

Host System: Kepler-1656

Spectral Class

G-type yellow (Sun-like)

Effective Temperature

5,569 K — cooler than the Sun (5,778 K)

Estimated Age

6.31 Gyr — older than the Sun (4.6 Gyr)

Stellar Radius

1.100 R☉

Stellar Mass

1.030 M☉

Metallicity [Fe/H]

0.19

Extended Stellar Properties

Surface gravity (log g)

4.400 dex

Stellar density

1.050 g/cm³

Systemic radial velocity

-39.29 km/s

Rotational v·sin i

2.80 km/s

Metallicity ratio

[Fe/H]

Distance

185.88 parsec

Light-years 606.24 ly

V-band magnitude

11.64 mag

Voyager-speed travel 10,691,085 yr

Multi-band Host Photometry — 17 bands

Astrometric Data

Parallax

5.351 mas

Total Proper Motion

20.615 mas/yr

PM Right Ascension

10.87 mas/yr

PM Declination

17.52 mas/yr

Galactic Cartesian (pc)

x = 0.192 · y = -0.743 · z = 0.642

Equatorial (J2000)

RA 284.47225° · Dec 39.91189°

Galactic ℓ, b

70.079° · 15.864°

Ecliptic λ, β

294.213° · 62.140°

HTM-20 index

-448263849