Key parameters at a glance

A radius of 3.15 Earth radii
A mass of 10.10 Earth masses
Surface gravity around 1.02 g
An orbital period of 3.174 days
Semi-major axis 0.0464 AU
Equilibrium temperature 1,655 K (1382 °C)
Distance from Earth 4,298.90 light-years
Earth Similarity Index 0.129
Travel time at Voyager 1 speed 75,811,082 years

Kepler-644 b Planet Profile

Physical Specs

Radius

3.15 R⊕

Radius (Jupiter)

0.281 R♃

Mass

10.10 M⊕

Mass (Jupiter)

0.032 M♃

Density

1.78 g/cm³

Surface Gravity

1.02 g (Earth)

Classification

Planet Type

Sub-Neptune

ESI Score 0.129

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

#391of 1978

top 19.7%

This planet

3.15R⊕

Sub-Neptune median

2.71R⊕

Nearest-size peers

Kepler-896 c 3.15 R⊕ Kepler-312 c 3.15 R⊕ Kepler-324 c 3.15 R⊕

Metric	Earth	Kepler-644 b	Jupiter
Radius (R⊕)	1.00	3.15	11.21
Mass (M⊕)	1.00	10.10	317.83
Density (g/cm³)	5.51	1.78	1.33
Surface Gravity (g)	1.00	1.02	2.53
Insolation (S⊕)	1.00	2,381.77	0.037

Star Catalogue Identifiers

TIC

TIC 271669616

Gaia DR2

Gaia DR2 2078049767888231936

Gaia DR3

Gaia DR3 2078049767888231936

System

Kepler-644

Percentile among Sub-Neptune cohort

Radius 3.150 R⊕ · percentile 80 / cohort 1978

Mass 10.100 M⊕ · percentile 73 / cohort 1978

Orbital period 3.17 d · percentile 5 / cohort 1946

Distance 1,318.05 pc · percentile 89 / cohort 1975

ESI 0.129 · percentile 1 / cohort 1978

Orbit & Habitability

Orbital Dynamics

Period

3.174 days

Semi-major axis

0.0464 AU

Eccentricity

0.000

Inclination

78.65 °

Year Length

A year here lasts approximately 3.17 Earth days (0.9% of a terrestrial year) on a nearly circular orbit at a mean orbital distance of 0.0464 AU.

Transit Fingerprint

Depth

0.030 %

Duration

3.507 h

Impact parameter b

0.629

Rp / R★

0.016354

Transit midpoint (BJD)

2,455,003.9244

Photometric dip

Transit produces a flux drop of 303 ppm lasting ≈ 3.51 h.

Extended Orbital Architecture

Planet / star radius ratio

0.016354

Semi-major axis / stellar radius

7.040

Impact parameter (b)

0.629

Transit mid-time (BJD)

2,455,003.9244

Angular separation (arcsec)

0.03520

Eq. Temperature

1,655K

(1382 °C)

Insolation (S⊕)

2,381.77

Earth = 1.00

Earth Similarity (ESI)

0.129

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-644

Spectral Class

F-type yellow-white

Effective Temperature

6,747 K — hotter than the Sun (5,778 K)

Estimated Age

1.62 Gyr — younger than the Sun (4.6 Gyr)

Stellar Radius

1.810 R☉

Stellar Mass

1.490 M☉

Metallicity [Fe/H]

0.08

Extended Stellar Properties

Surface gravity (log g)

4.090 dex

Stellar density

0.290 g/cm³

Metallicity ratio

[Fe/H]

Distance

1,318.05 parsec

Light-years 4,298.90 ly

V-band magnitude

14.03 mag

Voyager-speed travel 75,811,082 yr

Multi-band Host Photometry — 16 bands

Astrometric Data

Parallax

0.730 mas

Total Proper Motion

6.364 mas/yr

PM Right Ascension

-4.35 mas/yr

PM Declination

-4.64 mas/yr

Galactic Cartesian (pc)

x = 0.312 · y = -0.655 · z = 0.688

Equatorial (J2000)

RA 295.47570° · Dec 43.49311°

Galactic ℓ, b

76.980° · 9.952°

Ecliptic λ, β

313.646° · 63.124°

HTM-20 index

-1392784755