Key parameters at a glance

A radius of 2.32 Earth radii
A mass of 5.99 Earth masses
Surface gravity around 1.11 g
An orbital period of 5.654 days
Semi-major axis 0.0626 AU
Equilibrium temperature 1,020 K (747 °C)
Distance from Earth 3,217.09 light-years
Earth Similarity Index 0.252
Travel time at Voyager 1 speed 56,733,297 years

Kepler-998 b Planet Profile

Physical Specs

Radius

2.32 R⊕

Radius (Jupiter)

0.207 R♃

Mass

5.99 M⊕

Mass (Jupiter)

0.019 M♃

Density

2.64 g/cm³

Surface Gravity

1.11 g (Earth)

Classification

Planet Type

Sub-Neptune

ESI Score 0.252

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

#1469of 1978

top 74.2%

This planet

2.32R⊕

Sub-Neptune median

2.71R⊕

Nearest-size peers

Kepler-321 c 2.32 R⊕ K2-28 b 2.32 R⊕ Kepler-1208 b 2.32 R⊕

Metric	Earth	Kepler-998 b	Jupiter
Radius (R⊕)	1.00	2.32	11.21
Mass (M⊕)	1.00	5.99	317.83
Density (g/cm³)	5.51	2.64	1.33
Surface Gravity (g)	1.00	1.11	2.53
Insolation (S⊕)	1.00	409.92	0.037

Star Catalogue Identifiers

TIC

TIC 27914290

Gaia DR2

Gaia DR2 2086838576644246144

Gaia DR3

Gaia DR3 2086838576644246144

System

Kepler-998

Percentile among Sub-Neptune cohort

Radius 2.320 R⊕ · percentile 25 / cohort 1978

Mass 5.990 M⊕ · percentile 24 / cohort 1978

Orbital period 5.65 d · percentile 15 / cohort 1946

Distance 986.36 pc · percentile 77 / cohort 1975

ESI 0.252 · percentile 16 / cohort 1978

Orbit & Habitability

Orbital Dynamics

Period

5.654 days

Semi-major axis

0.0626 AU

Eccentricity

0.000

Inclination

88.77 °

Year Length

A year here lasts approximately 5.65 Earth days (1.5% of a terrestrial year) on a nearly circular orbit at a mean orbital distance of 0.0626 AU.

Transit Fingerprint

Depth

0.037 %

Duration

1.961 h

Impact parameter b

0.306

Rp / R★

0.018451

Transit midpoint (BJD)

2,454,964.7121

Photometric dip

Transit produces a flux drop of 367 ppm lasting ≈ 1.96 h.

Extended Orbital Architecture

Planet / star radius ratio

0.018451

Semi-major axis / stellar radius

21.400

Impact parameter (b)

0.306

Transit mid-time (BJD)

2,454,964.7121

Angular separation (arcsec)

0.06350

Eq. Temperature

1,020K

(747 °C)

Insolation (S⊕)

409.92

Earth = 1.00

Earth Similarity (ESI)

0.252

0 = alien, 1 = Earth-identical

Inside the inner HZ boundary (too hot for liquid water) — the dayside is scorched.

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-998

Spectral Class

F-type yellow-white

Effective Temperature

6,058 K — hotter than the Sun (5,778 K)

Estimated Age

3.31 Gyr — younger than the Sun (4.6 Gyr)

Stellar Radius

1.180 R☉

Stellar Mass

1.120 M☉

Metallicity [Fe/H]

0.07

Extended Stellar Properties

Surface gravity (log g)

4.340 dex

Stellar density

5.801 g/cm³

Metallicity ratio

[Fe/H]

Distance

986.36 parsec

Light-years 3,217.09 ly

V-band magnitude

14.46 mag

Voyager-speed travel 56,733,297 yr

Multi-band Host Photometry — 16 bands

Astrometric Data

Parallax

0.985 mas

Total Proper Motion

2.302 mas/yr

PM Right Ascension

1.87 mas/yr

PM Declination

-1.35 mas/yr

Galactic Cartesian (pc)

x = 0.294 · y = -0.583 · z = 0.757

Equatorial (J2000)

RA 296.75416° · Dec 49.20871°

Galactic ℓ, b

82.538° · 11.865°

Ecliptic λ, β

321.479° · 67.922°

HTM-20 index

1883599570