Key parameters at a glance

A radius of 0.90 Earth radii
A mass of 0.67 Earth masses
Surface gravity around 0.82 g
An orbital period of 2.788 days
Semi-major axis 0.0391 AU
Equilibrium temperature 1,510 K (1237 °C)
Distance from Earth 2,779.51 light-years
Earth Similarity Index 0.197
Travel time at Voyager 1 speed 49,016,735 years

1 sibling around Kepler-1398

Kepler-1398 b 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-1398 b this	Rocky Terrestrial	0.90	0.67	2.788	1,510	2016
Kepler-1398 c	Rocky Terrestrial	1.03	1.08	4.138	1,324	2016

Kepler-1398 b Planet Profile

Physical Specs

Radius

0.90 R⊕

Radius (Jupiter)

0.080 R♃

Mass

0.67 M⊕

Mass (Jupiter)

0.002 M♃

Density

5.02 g/cm³

Surface Gravity

0.82 g (Earth)

Classification

Planet Type

Rocky Terrestrial

ESI Score 0.197

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

#415of 570

top 72.6%

This planet

0.90R⊕

Rocky Terrestrial median

1.01R⊕

Nearest-size peers

Kepler-1547 b 0.90 R⊕ TOI-540 b 0.90 R⊕ Kepler-1759 b 0.90 R⊕

Metric	Earth	Kepler-1398 b	Jupiter
Radius (R⊕)	1.00	0.90	11.21
Mass (M⊕)	1.00	0.67	317.83
Density (g/cm³)	5.51	5.02	1.33
Surface Gravity (g)	1.00	0.82	2.53
Insolation (S⊕)	1.00	1,249.49	0.037

Star Catalogue Identifiers

TIC

TIC 27239111

Gaia DR2

Gaia DR2 2128776801985730048

Gaia DR3

Gaia DR3 2128776801985730048

System

Kepler-1398

Percentile among Rocky Terrestrial cohort

Radius 0.900 R⊕ · percentile 27 / cohort 570

Mass 0.666 M⊕ · percentile 23 / cohort 570

Orbital period 2.79 d · percentile 32 / cohort 567

Distance 852.20 pc · percentile 88 / cohort 566

ESI 0.197 · percentile 14 / cohort 570

Orbit & Habitability

Orbital Dynamics

Period

2.788 days

Semi-major axis

0.0391 AU

Eccentricity

0.000

Inclination

89.47 °

Year Length

A year here lasts approximately 2.79 Earth days (0.8% of a terrestrial year) on a nearly circular orbit at a mean orbital distance of 0.0391 AU.

Transit Fingerprint

Depth

0.006 %

Duration

3.326 h

Impact parameter b

0.058

Rp / R★

0.007194

Transit midpoint (BJD)

2,454,964.8522

Photometric dip

Transit produces a flux drop of 56 ppm lasting ≈ 3.33 h.

Extended Orbital Architecture

Planet / star radius ratio

0.007194

Semi-major axis / stellar radius

6.329

Impact parameter (b)

0.058

Transit mid-time (BJD)

2,454,964.8522

Angular separation (arcsec)

0.04590

Eq. Temperature

1,510K

(1237 °C)

Insolation (S⊕)

1,249.49

Earth = 1.00

Earth Similarity (ESI)

0.197

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-1398

Spectral Class

F-type yellow-white

Effective Temperature

6,126 K — hotter than the Sun (5,778 K)

Estimated Age

3.09 Gyr — younger than the Sun (4.6 Gyr)

Stellar Radius

1.180 R☉

Stellar Mass

1.130 M☉

Metallicity [Fe/H]

0.01

Extended Stellar Properties

Surface gravity (log g)

4.340 dex

Stellar density

0.500 g/cm³

Metallicity ratio

[Fe/H]

Distance

852.20 parsec

Light-years 2,779.51 ly

V-band magnitude

13.75 mag

Voyager-speed travel 49,016,735 yr

Multi-band Host Photometry — 16 bands

Astrometric Data

Parallax

1.145 mas

Total Proper Motion

10.537 mas/yr

PM Right Ascension

-10.54 mas/yr

PM Declination

0.03 mas/yr

Galactic Cartesian (pc)

x = 0.278 · y = -0.600 · z = 0.751

Equatorial (J2000)

RA 294.86611° · Dec 48.63899°

Galactic ℓ, b

81.436° · 12.703°

Ecliptic λ, β

317.846° · 67.989°

HTM-20 index

1641894403