Key parameters at a glance

A radius of 0.95 Earth radii
A mass of 1.40 Earth masses
Surface gravity around 1.54 g
An orbital period of 19.578 days
Semi-major axis 0.1387 AU
Equilibrium temperature 681 K (408 °C)
Distance from Earth 921.60 light-years
Earth Similarity Index 0.445
Travel time at Voyager 1 speed 16,252,348 years

Context from the literature

Kepler-20f (also known by its Kepler Object of Interest designation KOI-070.05) is an exoplanet orbiting the Sun-like star Kepler-20, the second outermost of five such planets discovered by NASA's Kepler spacecraft. It is located approximately 929 light-years (285 parsecs, or about 8.988×1015 km) from Earth in the constellation Lyra. The exoplanet was found by using the transit method, in which the dimming effect that a planet causes as it crosses in front of its star is measured. The planet is notable as it has the closest radius to Earth known so far.

Excerpted from Wikipedia · full article

5 siblings around Kepler-20

Kepler-20 f shares its host star with 5 other confirmed planets. Side-by-side measurements below.

Planet	Type	Radius (R⊕)	Mass (M⊕)	Period (d)	Eq. T (K)	Year
Kepler-20 b	Super-Earth	1.77	9.70	3.696	1,187	2011
Kepler-20 e	Rocky Terrestrial	0.82	0.76	6.098	1,004	2011
Kepler-20 c	Sub-Neptune	2.89	11.10	10.854	828	2011
Kepler-20 f this	Rocky Terrestrial	0.95	1.40	19.578	681	2011
Kepler-20 g	Neptune-like	4.71	19.96	34.940	524	2016
Kepler-20 d	Sub-Neptune	2.61	13.40	77.611	430	2011

Kepler-20 f Planet Profile

Physical Specs

Radius

0.95 R⊕

Radius (Jupiter)

0.085 R♃

Mass

1.40 M⊕

Mass (Jupiter)

0.004 M♃

Density

8.40 g/cm³

Surface Gravity

1.54 g (Earth)

Classification

Planet Type

Rocky Terrestrial

ESI Score 0.445

HZ Position Inner

Controversial No

Discovery

Year 2011

Method Transit

Facility Kepler

Telescope 0.95 m Kepler Telescope

Size rank in cohort

Rank by radius

#375of 570

top 65.6%

This planet

0.95R⊕

Rocky Terrestrial median

1.01R⊕

Nearest-size peers

TOI-700 e 0.95 R⊕ Kepler-1049 b 0.95 R⊕ Kepler-106 d 0.95 R⊕

Metric	Earth	Kepler-20 f	Jupiter
Radius (R⊕)	1.00	0.95	11.21
Mass (M⊕)	1.00	1.40	317.83
Density (g/cm³)	5.51	8.40	1.33
Surface Gravity (g)	1.00	1.54	2.53
Insolation (S⊕)	1.00	35.90	0.037

Alternative Mass Estimates

Method	Value	Interpretation
Best measured mass	1.400 M⊕	Direct mass measurement (not derived).

Star Catalogue Identifiers

TIC

TIC 158554588

Gaia DR2

Gaia DR2 2102548708017562112

Gaia DR3

Gaia DR3 2102548708017562112

System

Kepler-20

Percentile among Rocky Terrestrial cohort

Radius 0.952 R⊕ · percentile 34 / cohort 570

Mass 1.400 M⊕ · percentile 56 / cohort 570

Orbital period 19.58 d · percentile 91 / cohort 567

Distance 282.56 pc · percentile 38 / cohort 566

ESI 0.445 · percentile 65 / cohort 570

Orbit & Habitability

Orbital Dynamics

Period

19.578 days

Semi-major axis

0.1387 AU

Eccentricity

0.094

Inclination

88.79 °

Year Length

A year here lasts approximately 19.58 Earth days (5.4% of a terrestrial year) on a nearly circular orbit at a mean orbital distance of 0.1387 AU.

Transit Fingerprint

Depth

0.012 %

Duration

3.744 h

Impact parameter b

0.727

Rp / R★

0.009811

Transit midpoint (BJD)

2,454,968.1988

Photometric dip

Transit produces a flux drop of 116 ppm lasting ≈ 3.74 h.

Extended Orbital Architecture

Planet / star radius ratio

0.009811

Semi-major axis / stellar radius

44.568

Impact parameter (b)

0.727

RV semi-amplitude (K)

0.350 m/s

Transit mid-time (BJD)

2,454,968.1988

Angular separation (arcsec)

0.49100

Eq. Temperature

681K

(408 °C)

Insolation (S⊕)

35.90

Earth = 1.00

Earth Similarity (ESI)

0.445

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

Fressin et al. 2012

Instrument

Kepler CCD Array

Publication

2012-02

Observation locale

Space

Discovery cohort

Planets confirmed in 2011 at Kepler (12 shown).

Kepler-22 b · Sub-Neptune Kepler-20 d · Sub-Neptune Kepler-26 c · Sub-Neptune Kepler-19 c · Sub-Neptune Kepler-26 b · Sub-Neptune Kepler-28 c · Super-Earth Kepler-10 c · Sub-Neptune Kepler-42 d · Rocky Terrestrial Kepler-16 b · Neptune-like Kepler-28 b · Super-Earth Kepler-34 b · Neptune-like Kepler-29 c · Sub-Neptune

Host System: Kepler-20

Spectral Class

G-type yellow (Sun-like)

Effective Temperature

5,495 K — cooler than the Sun (5,778 K)

Estimated Age

5.60 Gyr — older than the Sun (4.6 Gyr)

Stellar Radius

0.916 R☉

Stellar Mass

0.929 M☉

Metallicity [Fe/H]

0.07

Extended Stellar Properties

Surface gravity (log g)

4.446 dex

Stellar density

1.360 g/cm³

Systemic radial velocity

-20.93 km/s

Rotational v·sin i

0.40 km/s

Metallicity ratio

[Fe/H]

Distance

282.56 parsec

Light-years 921.60 ly

V-band magnitude

12.61 mag

Voyager-speed travel 16,252,348 yr

Multi-band Host Photometry — 16 bands

Astrometric Data

Parallax

3.510 mas

Total Proper Motion

27.251 mas/yr

PM Right Ascension

-3.98 mas/yr

PM Declination

-26.96 mas/yr

Galactic Cartesian (pc)

x = 0.225 · y = -0.704 · z = 0.674

Equatorial (J2000)

RA 287.69799° · Dec 42.33858°

Galactic ℓ, b

73.377° · 14.573°

Ecliptic λ, β

300.714° · 63.902°

HTM-20 index

-1933436408

Wikipedia → Image: Wikimedia Commons · NASA/Ames/JPL-Caltech · Public domain