Confirmed Exoplanet Discovered 2017

K2-118 b

A sub-neptune orbiting the k-type orange K2-118, located approximately 1,049.3 light-years from Earth.

Key parameters at a glance

  • A radius of 2.54 Earth radii
  • A mass of 6.99 Earth masses
  • Surface gravity around 1.08 g
  • An orbital period of 50.921 days
  • Semi-major axis 0.2450 AU
  • Distance from Earth 1,049.32 light-years
  • Earth Similarity Index 0.698
  • Travel time at Voyager 1 speed 18,504,680 years

K2-118 b Planet Profile

Physical Specs

Radius
2.54 R⊕
Radius (Jupiter)
0.227 R♃
Mass
6.99 M⊕
Mass (Jupiter)
0.022 M♃
Density
2.34 g/cm³
Surface Gravity
1.08 g (Earth)

Classification

Planet Type

Sub-Neptune

ESI Score 0.698
HZ Position Inner
Controversial No

Discovery

Year 2017
Method Transit
Facility K2
Telescope 0.95 m Kepler Telescope

Size rank in cohort

Rank by radius

#1117of 1978

top 56.4%

This planet

2.54R⊕

Sub-Neptune median

2.71R⊕

Nearest-size peers

Metric Earth K2-118 b Jupiter
Radius (R⊕)1.002.5411.21
Mass (M⊕)1.006.99317.83
Density (g/cm³)5.512.341.33
Surface Gravity (g)1.001.082.53
Insolation (S⊕)1.004.300.037

Star Catalogue Identifiers

TIC

TIC 293496724

Gaia DR2

Gaia DR2 609814922864694400

Gaia DR3

Gaia DR3 609814922864694400

System

K2-118

Percentile among Sub-Neptune cohort

Radius 2.540 R⊕ · percentile 43 / cohort 1978
Mass 6.990 M⊕ · percentile 40 / cohort 1978
Orbital period 50.92 d · percentile 86 / cohort 1946
Distance 321.72 pc · percentile 37 / cohort 1975
ESI 0.698 · percentile 92 / cohort 1978

Orbit & Habitability

Orbital Dynamics

Period
50.921 days
Semi-major axis
0.2450 AU
Eccentricity
0.200
Inclination
89.50 °

Year Length

A year here lasts approximately 50.92 Earth days (13.9% of a terrestrial year) on a mildly elliptical path at a mean orbital distance of 0.2450 AU.

Transit Fingerprint

Depth

0.119 %

Duration

4.104 h

Rp / R★

0.031741

Transit midpoint (BJD)

2,457,160.4730

Photometric dip

Transit produces a flux drop of 1,193 ppm lasting ≈ 4.10 h.

Extended Orbital Architecture

Planet / star radius ratio

0.031741

Semi-major axis / stellar radius

71.820

Transit mid-time (BJD)

2,457,160.4730

Long. of periastron (ω)

58.67°

Angular separation (arcsec)

0.76200

Eq. Temperature

 

Insolation (S⊕)

4.30

Earth = 1.00

Earth Similarity (ESI)

0.698

0 = alien, 1 = Earth-identical

Discovery Paper

Primary reference

Dressing et al. 2017

Instrument

Kepler CCD Array

Publication

2017-11

Observation locale

Space

Host System: K2-118

Spectral Class

K-type orange

Effective Temperature

4,726 K — cooler than the Sun (5,778 K)

Estimated Age

Stellar Radius

0.735 R☉

Stellar Mass

0.756 M☉

Metallicity [Fe/H]

0.13

Extended Stellar Properties

Surface gravity (log g)

4.534 dex

Stellar density

2.227 g/cm³

Metallicity ratio

[M/H]

Distance
321.72 parsec
Light-years 1,049.32 ly
V-band magnitude
14.00 mag
Voyager-speed travel 18,504,680 yr

Multi-band Host Photometry — 17 bands

8.716.716.70U15.03B14.00V13.75Gaia13.73Kepler13.13TESS14.84Sloan g15.04Sloan r14.93Sloan i13.44Sloan z12.26J11.77H11.65K11.63W111.70W211.82W38.69W4

Astrometric Data

Parallax

3.080 mas

Total Proper Motion

20.976 mas/yr

PM Right Ascension

-7.56 mas/yr

PM Declination

-19.57 mas/yr

Galactic Cartesian (pc)

x = -0.646 · y = 0.714 · z = 0.270

Equatorial (J2000)

RA 132.12686° · Dec 15.65590°

Galactic ℓ, b

211.192° · 32.821°

Ecliptic λ, β

130.261° · -2.091°

HTM-20 index

-1572591782

Similar Worlds

Explore Related Categories