Key parameters at a glance

A radius of 2.51 Earth radii
A mass of 6.85 Earth masses
Surface gravity around 1.09 g
An orbital period of 4.871 days
Semi-major axis 0.0301 AU
Equilibrium temperature 341 K (68 °C)
Distance from Earth 414.87 light-years
Earth Similarity Index 0.679
Travel time at Voyager 1 speed 7,316,297 years
Almost certainly tidally locked to its host star given the close orbit

Context from the literature

Kepler-445 is a red dwarf star located 401 light-years away in the constellation Cygnus. It hosts three known exoplanets, discovered by the transit method using data from the Kepler space telescope and confirmed in 2015. None of the planets orbit within the habitable zone.

Excerpted from Wikipedia · full article

2 siblings around Kepler-445

Kepler-445 c shares its host star with 2 other confirmed planets. Side-by-side measurements below.

Planet	Type	Radius (R⊕)	Mass (M⊕)	Period (d)	Eq. T (K)	Year
Kepler-445 b	Super-Earth	1.58	3.12	2.984	401	2015
Kepler-445 c this	Sub-Neptune	2.51	6.85	4.871	341	2015
Kepler-445 d	Super-Earth	1.25	2.10	8.153	305	2015

Kepler-445 c Planet Profile

Physical Specs

Radius

2.51 R⊕

Radius (Jupiter)

0.220 R♃

Mass

6.85 M⊕

Mass (Jupiter)

0.022 M♃

Density

2.38 g/cm³

Surface Gravity

1.09 g (Earth)

Classification

Planet Type

Sub-Neptune

ESI Score 0.679

HZ Position Inner

Controversial No

Discovery

Year 2015

Method Transit

Facility Kepler

Telescope 0.95 m Kepler Telescope

Size rank in cohort

Rank by radius

#1159of 1978

top 58.5%

This planet

2.51R⊕

Sub-Neptune median

2.71R⊕

Nearest-size peers

GJ 876 d 2.51 R⊕ Kepler-309 c 2.51 R⊕ Kepler-239 c 2.51 R⊕

Metric	Earth	Kepler-445 c	Jupiter
Radius (R⊕)	1.00	2.51	11.21
Mass (M⊕)	1.00	6.85	317.83
Density (g/cm³)	5.51	2.38	1.33
Surface Gravity (g)	1.00	1.09	2.53
Insolation (S⊕)	1.00	9.18	0.037

Star Catalogue Identifiers

TIC

TIC 268060194

Gaia DR2

Gaia DR2 2085482775729637376

Gaia DR3

Gaia DR3 2085482775729637376

System

Kepler-445

Percentile among Sub-Neptune cohort

Radius 2.510 R⊕ · percentile 41 / cohort 1978

Mass 6.850 M⊕ · percentile 38 / cohort 1978

Orbital period 4.87 d · percentile 12 / cohort 1946

Distance 127.20 pc · percentile 24 / cohort 1975

ESI 0.679 · percentile 91 / cohort 1978

Orbit & Habitability

Orbital Dynamics

Period

4.871 days

Semi-major axis

0.0301 AU

Eccentricity

0.000

Inclination

89.91 °

Year Length

A year here lasts approximately 4.87 Earth days (1.3% of a terrestrial year) on a nearly circular orbit at a mean orbital distance of 0.0301 AU.

Transit Fingerprint

Depth

0.646 %

Duration

1.229 h

Impact parameter b

0.000

Rp / R★

0.107500

Transit midpoint (BJD)

2,454,966.6408

Photometric dip

Transit produces a flux drop of 6,462 ppm lasting ≈ 1.23 h.

Extended Orbital Architecture

Planet / star radius ratio

0.107500

Semi-major axis / stellar radius

30.210

Impact parameter (b)

0.000

Transit mid-time (BJD)

2,454,966.6408

Angular separation (arcsec)

0.23700

Eq. Temperature

341K

(68 °C)

Insolation (S⊕)

9.18

Earth = 1.00

Earth Similarity (ESI)

0.679

0 = alien, 1 = Earth-identical

Inside the inner HZ boundary (too hot for liquid water) — liquid water is physically possible with adequate atmospheric pressure. Close-orbiting tidally-locked around a cool host.

Discovery Paper

Primary reference

Muirhead et al. 2015

Instrument

Kepler CCD Array

Publication

2015-03

Observation locale

Space

Discovery cohort

Planets confirmed in 2015 at Kepler (12 shown).

Kepler-438 b · Rocky Terrestrial Kepler-445 d · Super-Earth Kepler-442 b · Super-Earth Kepler-439 b · Sub-Neptune Kepler-437 b · Sub-Neptune Kepler-440 b · Super-Earth KIC 8540376 c · Sub-Neptune Kepler-445 b · Super-Earth Kepler-446 d · Super-Earth Kepler-436 b · Sub-Neptune Kepler-443 b · Sub-Neptune Kepler-441 b · Super-Earth

Host System: Kepler-445

Spectral Class

M-type red dwarf

Effective Temperature

3,157 K — cooler than the Sun (5,778 K)

Estimated Age

6.61 Gyr — older than the Sun (4.6 Gyr)

Stellar Radius

0.210 R☉

Stellar Mass

0.180 M☉

Metallicity [Fe/H]

0.27

Extended Stellar Properties

Surface gravity (log g)

4.925 dex

Stellar density

14.393 g/cm³

Systemic radial velocity

-61.00 km/s

Metallicity ratio

[Fe/H]

Distance

127.20 parsec

Light-years 414.87 ly

V-band magnitude

18.19 mag

Voyager-speed travel 7,316,297 yr

Multi-band Host Photometry — 14 bands

Astrometric Data

Parallax

7.833 mas

Total Proper Motion

138.540 mas/yr

PM Right Ascension

41.52 mas/yr

PM Declination

132.17 mas/yr

Galactic Cartesian (pc)

x = 0.331 · y = -0.604 · z = 0.725

Equatorial (J2000)

RA 298.73634° · Dec 46.49912°

Galactic ℓ, b

80.780° · 9.390°

Ecliptic λ, β

321.285° · 64.904°

HTM-20 index

31717645

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