Confirmed Exoplanet Discovered 2014

Kepler-357 c

A sub-neptune orbiting the k-type orange Kepler-357, located approximately 2,245.8 light-years from Earth.

Key parameters at a glance

  • A radius of 2.67 Earth radii
  • A mass of 7.61 Earth masses
  • Surface gravity around 1.07 g
  • An orbital period of 16.858 days
  • Semi-major axis 0.1200 AU
  • Equilibrium temperature 576 K (303 °C)
  • Distance from Earth 2,245.82 light-years
  • Earth Similarity Index 0.426
  • Travel time at Voyager 1 speed 39,605,071 years
  • Almost certainly tidally locked to its host star given the close orbit

2 siblings around Kepler-357

Kepler-357 c shares its host star with 2 other confirmed planets. Side-by-side measurements below.

Planet Type Radius (R⊕) Mass (M⊕) Period (d) Eq. T (K) Year
Kepler-357 b Super-Earth 1.84 4.04 6.475 793 2014
Kepler-357 c this Sub-Neptune 2.67 7.61 16.858 576 2014
Kepler-357 d Sub-Neptune 3.43 11.60 49.500 402 2014

Kepler-357 c Planet Profile

Physical Specs

Radius
2.67 R⊕
Radius (Jupiter)
0.238 R♃
Mass
7.61 M⊕
Mass (Jupiter)
0.024 M♃
Density
2.20 g/cm³
Surface Gravity
1.07 g (Earth)

Classification

Planet Type

Sub-Neptune

ESI Score 0.426
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

#904of 1978

top 45.7%

This planet

2.67R⊕

Sub-Neptune median

2.71R⊕

Nearest-size peers

Metric Earth Kepler-357 c Jupiter
Radius (R⊕)1.002.6711.21
Mass (M⊕)1.007.61317.83
Density (g/cm³)5.512.201.33
Surface Gravity (g)1.001.072.53
Insolation (S⊕)1.0019.400.037

Star Catalogue Identifiers

TIC

TIC 159649595

Gaia DR2

Gaia DR2 2126194667646233984

Gaia DR3

Gaia DR3 2126194667646233984

System

Kepler-357

Percentile among Sub-Neptune cohort

Radius 2.670 R⊕ · percentile 53 / cohort 1978
Mass 7.610 M⊕ · percentile 49 / cohort 1978
Orbital period 16.86 d · percentile 56 / cohort 1946
Distance 688.57 pc · percentile 59 / cohort 1975
ESI 0.426 · percentile 58 / cohort 1978

Orbit & Habitability

Orbital Dynamics

Period
16.858 days
Semi-major axis
0.1200 AU
Eccentricity
0.000
Inclination
88.98 °

Year Length

A year here lasts approximately 16.86 Earth days (4.6% of a terrestrial year) on a nearly circular orbit at a mean orbital distance of 0.1200 AU.

Transit Fingerprint

Depth

0.076 %

Duration

2.016 h

Impact parameter b

0.820

Rp / R★

0.027868

Transit midpoint (BJD)

2,454,975.3426

Photometric dip

Transit produces a flux drop of 760 ppm lasting ≈ 2.02 h.

Extended Orbital Architecture

Planet / star radius ratio

0.027868

Semi-major axis / stellar radius

32.400

Impact parameter (b)

0.820

Transit mid-time (BJD)

2,454,975.3426

Angular separation (arcsec)

0.17400

Eq. Temperature

576K

(303 °C)

Insolation (S⊕)

19.40

Earth = 1.00

Earth Similarity (ESI)

0.426

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

Host System: Kepler-357

Spectral Class

K-type orange

Effective Temperature

5,036 K — cooler than the Sun (5,778 K)

Estimated Age

2.14 Gyr — younger than the Sun (4.6 Gyr)

Stellar Radius

0.834 R☉

Stellar Mass

0.794 M☉

Metallicity [Fe/H]

0.06

Extended Stellar Properties

Surface gravity (log g)

4.503 dex

Stellar density

1.990 g/cm³

Metallicity ratio

[Fe/H]

Distance
688.57 parsec
Light-years 2,245.82 ly
V-band magnitude
15.74 mag
Voyager-speed travel 39,605,071 yr

Multi-band Host Photometry — 16 bands

9.416.916.94B15.74V15.52Gaia15.57Kepler14.90TESS16.36Sloan g15.50Sloan r15.23Sloan i15.10Sloan z13.99J13.51H13.41K13.36W113.48W212.58W39.36W4

Astrometric Data

Parallax

1.424 mas

Total Proper Motion

23.039 mas/yr

PM Right Ascension

-15.32 mas/yr

PM Declination

-17.21 mas/yr

Galactic Cartesian (pc)

x = 0.261 · y = -0.670 · z = 0.695

Equatorial (J2000)

RA 291.24297° · Dec 44.00863°

Galactic ℓ, b

76.045° · 12.913°

Ecliptic λ, β

307.572° · 64.701°

HTM-20 index

800219681

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