Key parameters at a glance

A radius of 6.80 Earth radii
A mass of 37.20 Earth masses
Surface gravity around 0.80 g
An orbital period of 85.351 days
Semi-major axis 0.3751 AU
Equilibrium temperature 390 K (117 °C)
Distance from Earth 3,207.75 light-years
Earth Similarity Index 0.396
Travel time at Voyager 1 speed 56,568,682 years

Kepler-857 b Planet Profile

Physical Specs

Radius

6.80 R⊕

Radius (Jupiter)

0.607 R♃

Mass

37.20 M⊕

Mass (Jupiter)

0.117 M♃

Density

0.65 g/cm³

Surface Gravity

0.80 g (Earth)

Classification

Planet Type

Neptune-like

ESI Score 0.396

HZ Position Inner

Controversial No

Discovery

Year 2016

Method Transit

Facility Kepler

Telescope 0.95 m Kepler Telescope

Size rank in cohort

Rank by radius

#220of 574

top 38.2%

This planet

6.80R⊕

Neptune-like median

6.39R⊕

Nearest-size peers

TOI-4600 b 6.80 R⊕ HATS-37 A b 6.79 R⊕ TOI-1248 b 6.81 R⊕

Metric	Earth	Kepler-857 b	Jupiter
Radius (R⊕)	1.00	6.80	11.21
Mass (M⊕)	1.00	37.20	317.83
Density (g/cm³)	5.51	0.65	1.33
Surface Gravity (g)	1.00	0.80	2.53
Insolation (S⊕)	1.00	5.75	0.037

Star Catalogue Identifiers

TIC

TIC 271158887

Gaia DR2

Gaia DR2 2078176589682140160

Gaia DR3

Gaia DR3 2078176589682140160

System

Kepler-857

Percentile among Neptune-like cohort

Radius 6.800 R⊕ · percentile 61 / cohort 574

Mass 37.200 M⊕ · percentile 60 / cohort 574

Orbital period 85.35 d · percentile 79 / cohort 524

Distance 983.50 pc · percentile 73 / cohort 572

ESI 0.396 · percentile 72 / cohort 574

Orbit & Habitability

Orbital Dynamics

Period

85.351 days

Semi-major axis

0.3751 AU

Eccentricity

0.000

Inclination

89.97 °

Year Length

A year here lasts approximately 85.35 Earth days (23.4% of a terrestrial year) on a nearly circular orbit at a mean orbital distance of 0.3751 AU.

Transit Fingerprint

Depth

0.487 %

Duration

6.757 h

Impact parameter b

0.684

Rp / R★

0.063366

Transit midpoint (BJD)

2,454,994.0093

Photometric dip

Transit produces a flux drop of 4,875 ppm lasting ≈ 6.76 h.

Extended Orbital Architecture

Planet / star radius ratio

0.063366

Semi-major axis / stellar radius

102.424

Impact parameter (b)

0.684

Transit mid-time (BJD)

2,454,994.0093

Angular separation (arcsec)

0.38100

Eq. Temperature

390K

(117 °C)

Insolation (S⊕)

5.75

Earth = 1.00

Earth Similarity (ESI)

0.396

0 = alien, 1 = Earth-identical

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

Discovery Paper

Primary reference

Morton et al. 2016

Instrument

Kepler CCD Array

Publication

2016-05

Observation locale

Space

Discovery cohort

Planets confirmed in 2016 at Kepler (12 shown).

Kepler-1512 b · Rocky Terrestrial Kepler-1410 b · Super-Earth Kepler-560 b · Super-Earth Kepler-1389 b · Super-Earth Kepler-1450 b · Super-Earth Kepler-1544 b · Super-Earth Kepler-1459 b · Super-Earth Kepler-1638 b · Super-Earth Kepler-737 b · Super-Earth Kepler-1185 b · Super-Earth Kepler-1178 b · Rocky Terrestrial Kepler-1040 b · Sub-Neptune

Host System: Kepler-857

Spectral Class

G-type yellow (Sun-like)

Effective Temperature

5,773 K — cooler than the Sun (5,778 K)

Estimated Age

4.27 Gyr — younger than the Sun (4.6 Gyr)

Stellar Radius

0.990 R☉

Stellar Mass

0.990 M☉

Metallicity [Fe/H]

0.02

Extended Stellar Properties

Surface gravity (log g)

4.450 dex

Stellar density

2.764 g/cm³

Metallicity ratio

[Fe/H]

Distance

983.50 parsec

Light-years 3,207.75 ly

V-band magnitude

15.17 mag

Voyager-speed travel 56,568,682 yr

Multi-band Host Photometry — 16 bands

Astrometric Data

Parallax

0.989 mas

Total Proper Motion

5.018 mas/yr

PM Right Ascension

-4.14 mas/yr

PM Declination

-2.83 mas/yr

Galactic Cartesian (pc)

x = 0.303 · y = -0.660 · z = 0.687

Equatorial (J2000)

RA 294.63240° · Dec 43.40045°

Galactic ℓ, b

76.606° · 10.449°

Ecliptic λ, β

312.310° · 63.266°

HTM-20 index

-1413458181