Artist impression of Kepler-11 g exoplanet
Confirmed Exoplanet Discovered 2010

Kepler-11 g

A sub-neptune orbiting the g-type yellow (sun-like) Kepler-11, located approximately 2,108.1 light-years from Earth.

Image: Wikimedia Commons · CC BY-SA 3.0 · Aldaron, a.k.a. Aldaron

Key parameters at a glance

  • A radius of 3.33 Earth radii
  • A mass of 25.00 Earth masses
  • Surface gravity around 2.25 g
  • An orbital period of 118.381 days
  • Semi-major axis 0.4660 AU
  • Equilibrium temperature 376 K (103 °C)
  • Distance from Earth 2,108.10 light-years
  • Earth Similarity Index 0.629
  • Travel time at Voyager 1 speed 37,176,275 years

Context from the literature

Kepler-11g is an exoplanet discovered in the orbit of the sunlike star Kepler-11 by the Kepler space telescope, a NASA satellite tasked with searching for terrestrial planets. Kepler-11g is the outermost of the star's six planets. The planet orbits at a distance of nearly half the mean distance between Earth and the Sun. It completes an orbit every 118 days, placing it much further from its star than the system's inner five planets. Its estimated radius is a little over three times that of Earth, i.e. comparable to Neptune's size. Kepler-11g's distance from the inner planets made its confirmation more difficult than that of the inner planets, as scientists had to work to exhaustively disprove all reasonable alternatives before Kepler-11g could be confirmed. The planet's discovery, along with that of the other Kepler-11 planets, was announced on February 2, 2011. According to NASA, the Kepler-11 planets form the flattest and most compact system yet discovered.

Excerpted from Wikipedia · full article

5 siblings around Kepler-11

Kepler-11 g 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-11 b Super-Earth 1.80 1.90 10.304 849 2010
Kepler-11 c Sub-Neptune 2.87 2.90 13.024 786 2010
Kepler-11 d Sub-Neptune 3.12 7.30 22.685 653 2010
Kepler-11 e Neptune-like 4.19 8.00 32.000 582 2010
Kepler-11 f Sub-Neptune 2.49 2.00 46.689 513 2010
Kepler-11 g this Sub-Neptune 3.33 25.00 118.381 376 2010

Kepler-11 g Planet Profile

Physical Specs

Radius
3.33 R⊕
Radius (Jupiter)
0.297 R♃
Mass
25.00 M⊕
Mass (Jupiter)
0.079 M♃
Density
4.00 g/cm³
Surface Gravity
2.25 g (Earth)

Classification

Planet Type

Sub-Neptune

ESI Score 0.629
HZ Position Inner
Controversial No

Discovery

Year 2010
Method Transit
Facility Kepler
Telescope 0.95 m Kepler Telescope

Size rank in cohort

Rank by radius

#261of 1978

top 13.1%

This planet

3.33R⊕

Sub-Neptune median

2.71R⊕

Nearest-size peers

Metric Earth Kepler-11 g Jupiter
Radius (R⊕)1.003.3311.21
Mass (M⊕)1.0025.00317.83
Density (g/cm³)5.514.001.33
Surface Gravity (g)1.002.252.53
Insolation (S⊕)1.005.650.037

Alternative Mass Estimates

Method Value Interpretation
Best measured mass 25.000 M⊕ Direct mass measurement (not derived).
Minimum mass (M sin i) 8.826 M⊕ Lower bound from radial-velocity fitting.

Star Catalogue Identifiers

TIC

TIC 169175503

Gaia DR2

Gaia DR2 2076960598545789824

Gaia DR3

Gaia DR3 2076960598545789824

System

Kepler-11

Percentile among Sub-Neptune cohort

Radius 3.330 R⊕ · percentile 87 / cohort 1978
Mass 25.000 M⊕ · percentile 96 / cohort 1978
Orbital period 118.38 d · percentile 95 / cohort 1946
Distance 646.35 pc · percentile 56 / cohort 1975
ESI 0.629 · percentile 86 / cohort 1978

Orbit & Habitability

Orbital Dynamics

Period
118.381 days
Semi-major axis
0.4660 AU
Eccentricity
0.150
Inclination
89.87 °

Year Length

A year here lasts approximately 118.38 Earth days (32.4% of a terrestrial year) on a mildly elliptical path at a mean orbital distance of 0.4660 AU.

Transit Fingerprint

Depth

0.101 %

Duration

9.469 h

Impact parameter b

0.217

Rp / R★

0.028990

Transit midpoint (BJD)

2,455,593.8021

Photometric dip

Transit produces a flux drop of 1,006 ppm lasting ≈ 9.47 h.

Extended Orbital Architecture

Planet / star radius ratio

0.028990

Semi-major axis / stellar radius

94.400

Impact parameter (b)

0.217

RV semi-amplitude (K)

0.014 m/s

Transit mid-time (BJD)

2,455,593.8021

Long. of periastron (ω)

97.00°

Angular separation (arcsec)

0.72100

Eq. Temperature

376K

(103 °C)

Insolation (S⊕)

5.65

Earth = 1.00

Earth Similarity (ESI)

0.629

0 = alien, 1 = Earth-identical

Inside the inner HZ boundary (too hot for liquid water) — the surface is too hot to retain surface water.

Detection Signatures

Transit photometry

A transit dip has been observed from at least one telescope.

Radial velocity

Stellar wobble has been measured spectroscopically.

Transit timing variations

Gravitational interactions from neighbours have been detected.

Discovery Paper

Primary reference

Lissauer et al. 2011

Instrument

Kepler CCD Array

Publication

2011-02

Observation locale

Space

Host System: Kepler-11

Spectral Class

G-type yellow (Sun-like)

Effective Temperature

5,663 K — cooler than the Sun (5,778 K)

Estimated Age

8.50 Gyr — older than the Sun (4.6 Gyr)

Stellar Radius

1.065 R☉

Stellar Mass

0.961 M☉

Metallicity [Fe/H]

0.05

Extended Stellar Properties

Surface gravity (log g)

4.366 dex

Stellar density

1.122 g/cm³

Systemic radial velocity

-57.16 km/s

Rotational v·sin i

0.40 km/s

Metallicity ratio

[Fe/H]

Distance
646.35 parsec
Light-years 2,108.10 ly
V-band magnitude
13.82 mag
Voyager-speed travel 37,176,275 yr

Multi-band Host Photometry — 16 bands

9.414.614.64B13.82V13.71Gaia13.71Kepler13.24TESS14.18Sloan g13.65Sloan r13.51Sloan i13.46Sloan z12.55J12.24H12.18K12.05W112.13W212.12W39.44W4

Astrometric Data

Parallax

1.518 mas

Total Proper Motion

7.069 mas/yr

PM Right Ascension

-0.04 mas/yr

PM Declination

-7.07 mas/yr

Galactic Cartesian (pc)

x = 0.339 · y = -0.662 · z = 0.668

Equatorial (J2000)

RA 297.11509° · Dec 41.90911°

Galactic ℓ, b

76.161° · 8.133°

Ecliptic λ, β

314.755° · 61.202°

HTM-20 index

-842633374

Wikipedia → Image: Wikimedia Commons · Aldaron, a.k.a. Aldaron · CC BY-SA 3.0

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