Key parameters at a glance

A radius of 2.37 Earth radii
A mass of 6.21 Earth masses
Surface gravity around 1.11 g
An orbital period of 29.008 days
Semi-major axis 0.1759 AU
Equilibrium temperature 498 K (225 °C)
Distance from Earth 2,158.75 light-years
Earth Similarity Index 0.508
Travel time at Voyager 1 speed 38,069,524 years

Kepler-558 b Planet Profile

Physical Specs

Radius

2.37 R⊕

Radius (Jupiter)

0.211 R♃

Mass

6.21 M⊕

Mass (Jupiter)

0.020 M♃

Density

2.56 g/cm³

Surface Gravity

1.11 g (Earth)

Classification

Planet Type

Sub-Neptune

ESI Score 0.508

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

#1375of 1978

top 69.5%

This planet

2.37R⊕

Sub-Neptune median

2.71R⊕

Nearest-size peers

Kepler-81 c 2.37 R⊕ K2-18 b 2.37 R⊕ Kepler-125 b 2.37 R⊕

Metric	Earth	Kepler-558 b	Jupiter
Radius (R⊕)	1.00	2.37	11.21
Mass (M⊕)	1.00	6.21	317.83
Density (g/cm³)	5.51	2.56	1.33
Surface Gravity (g)	1.00	1.11	2.53
Insolation (S⊕)	1.00	15.23	0.037

Star Catalogue Identifiers

TIC

TIC 164730843

Gaia DR2

Gaia DR2 2104251370492901760

Gaia DR3

Gaia DR3 2104251370492901760

System

Kepler-558

Percentile among Sub-Neptune cohort

Radius 2.370 R⊕ · percentile 30 / cohort 1978

Mass 6.210 M⊕ · percentile 29 / cohort 1978

Orbital period 29.01 d · percentile 73 / cohort 1946

Distance 661.88 pc · percentile 57 / cohort 1975

ESI 0.508 · percentile 71 / cohort 1978

Orbit & Habitability

Orbital Dynamics

Period

29.008 days

Semi-major axis

0.1759 AU

Eccentricity

0.000

Inclination

88.57 °

Year Length

A year here lasts approximately 29.01 Earth days (7.9% of a terrestrial year) on a nearly circular orbit at a mean orbital distance of 0.1759 AU.

Transit Fingerprint

Depth

0.091 %

Duration

4.826 h

Impact parameter b

0.937

Rp / R★

0.026881

Transit midpoint (BJD)

2,455,003.5541

Photometric dip

Transit produces a flux drop of 906 ppm lasting ≈ 4.83 h.

Extended Orbital Architecture

Planet / star radius ratio

0.026881

Semi-major axis / stellar radius

47.063

Impact parameter (b)

0.937

Transit mid-time (BJD)

2,455,003.5541

Angular separation (arcsec)

0.26600

Eq. Temperature

498K

(225 °C)

Insolation (S⊕)

15.23

Earth = 1.00

Earth Similarity (ESI)

0.508

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-558

Spectral Class

G-type yellow (Sun-like)

Effective Temperature

5,242 K — cooler than the Sun (5,778 K)

Estimated Age

4.47 Gyr — younger than the Sun (4.6 Gyr)

Stellar Radius

0.810 R☉

Stellar Mass

0.850 M☉

Metallicity [Fe/H]

-0.06

Extended Stellar Properties

Surface gravity (log g)

4.560 dex

Stellar density

2.344 g/cm³

Metallicity ratio

[Fe/H]

Distance

661.88 parsec

Light-years 2,158.75 ly

V-band magnitude

14.90 mag

Voyager-speed travel 38,069,524 yr

Multi-band Host Photometry — 16 bands

Astrometric Data

Parallax

1.482 mas

Total Proper Motion

9.148 mas/yr

PM Right Ascension

8.17 mas/yr

PM Declination

-4.12 mas/yr

Galactic Cartesian (pc)

x = 0.186 · y = -0.712 · z = 0.678

Equatorial (J2000)

RA 284.65797° · Dec 42.65268°

Galactic ℓ, b

72.781° · 16.763°

Ecliptic λ, β

295.894° · 64.780°

HTM-20 index

1490641683