Confirmed Exoplanet Discovered 2020

Kepler-598 c

A sub-neptune orbiting the g-type yellow (sun-like) Kepler-598, located approximately 2,221.4 light-years from Earth.

Key parameters at a glance

  • A radius of 3.02 Earth radii
  • A mass of 9.40 Earth masses
  • Surface gravity around 1.03 g
  • An orbital period of 86.495 days
  • Semi-major axis 0.3667 AU
  • Equilibrium temperature 367 K (94 °C)
  • Distance from Earth 2,221.40 light-years
  • Earth Similarity Index 0.596
  • Travel time at Voyager 1 speed 39,174,437 years

1 sibling around Kepler-598

Kepler-598 c 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-598 b Super-Earth 1.50 2.86 3.702 1,050 2016
Kepler-598 c this Sub-Neptune 3.02 9.40 86.495 367 2020

Kepler-598 c Planet Profile

Physical Specs

Radius
3.02 R⊕
Radius (Jupiter)
0.270 R♃
Mass
9.40 M⊕
Mass (Jupiter)
0.030 M♃
Density
1.87 g/cm³
Surface Gravity
1.03 g (Earth)

Classification

Planet Type

Sub-Neptune

ESI Score 0.596
HZ Position Inner
Controversial No

Discovery

Year 2020
Method Transit
Facility Kepler
Telescope 0.95 m Kepler Telescope

Size rank in cohort

Rank by radius

#500of 1978

top 25.2%

This planet

3.02R⊕

Sub-Neptune median

2.71R⊕

Nearest-size peers

Metric Earth Kepler-598 c Jupiter
Radius (R⊕)1.003.0211.21
Mass (M⊕)1.009.40317.83
Density (g/cm³)5.511.871.33
Surface Gravity (g)1.001.032.53
Insolation (S⊕)1.003.700.037

Star Catalogue Identifiers

TIC

TIC 137969066

Gaia DR2

Gaia DR2 2053546910744629504

Gaia DR3

Gaia DR3 2053546910744629504

System

Kepler-598

Percentile among Sub-Neptune cohort

Radius 3.024 R⊕ · percentile 75 / cohort 1978
Mass 9.400 M⊕ · percentile 68 / cohort 1978
Orbital period 86.49 d · percentile 93 / cohort 1946
Distance 681.09 pc · percentile 58 / cohort 1975
ESI 0.596 · percentile 82 / cohort 1978

Orbit & Habitability

Orbital Dynamics

Period
86.495 days
Semi-major axis
0.3667 AU
Eccentricity
0.000
Inclination
89.33 °

Year Length

A year here lasts approximately 86.49 Earth days (23.7% of a terrestrial year) on a nearly circular orbit at a mean orbital distance of 0.3667 AU.

Transit Fingerprint

Depth

0.105 %

Duration

7.284 h

Impact parameter b

0.020

Rp / R★

0.027210

Transit midpoint (BJD)

2,455,014.8897

Photometric dip

Transit produces a flux drop of 1,046 ppm lasting ≈ 7.28 h.

Extended Orbital Architecture

Planet / star radius ratio

0.027210

Semi-major axis / stellar radius

91.600

Impact parameter (b)

0.020

Transit mid-time (BJD)

2,455,014.8897

Angular separation (arcsec)

0.53800

Eq. Temperature

367K

(94 °C)

Insolation (S⊕)

3.70

Earth = 1.00

Earth Similarity (ESI)

0.596

0 = alien, 1 = Earth-identical

Inside the inner HZ boundary (too hot for liquid water) — liquid water is physically possible with adequate atmospheric pressure.

Discovery Paper

Primary reference

Armstrong et al. 2021

Instrument

Kepler CCD Array

Publication

2021-07

Observation locale

Space

Host System: Kepler-598

Spectral Class

G-type yellow (Sun-like)

Effective Temperature

5,245 K — cooler than the Sun (5,778 K)

Estimated Age

12.30 Gyr — older than the Sun (4.6 Gyr)

Stellar Radius

0.900 R☉

Stellar Mass

0.900 M☉

Metallicity [Fe/H]

0.03

Extended Stellar Properties

Surface gravity (log g)

4.484 dex

Stellar density

1.739 g/cm³

Metallicity ratio

[M/H]

Distance
681.09 parsec
Light-years 2,221.40 ly
V-band magnitude
14.83 mag
Voyager-speed travel 39,174,437 yr

Multi-band Host Photometry — 16 bands

9.315.715.69B14.83V14.72Gaia14.76Kepler14.18TESS15.37Sloan g14.69Sloan r14.50Sloan i14.40Sloan z13.41J12.98H12.93K12.90W112.97W212.97W39.28W4

Astrometric Data

Parallax

1.440 mas

Total Proper Motion

7.235 mas/yr

PM Right Ascension

3.57 mas/yr

PM Declination

6.29 mas/yr

Galactic Cartesian (pc)

x = 0.297 · y = -0.695 · z = 0.655

Equatorial (J2000)

RA 293.12345° · Dec 40.93480°

Galactic ℓ, b

73.857° · 10.309°

Ecliptic λ, β

308.211° · 61.342°

HTM-20 index

1938677140

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