Confirmed Exoplanet Discovered 2016

K2-47 b

A super-earth orbiting the k-type orange K2-47, located approximately 1,141.2 light-years from Earth.

Key parameters at a glance

  • A radius of 1.89 Earth radii
  • A mass of 4.23 Earth masses
  • Surface gravity around 1.18 g
  • An orbital period of 31.637 days
  • Semi-major axis 0.1779 AU
  • Distance from Earth 1,141.16 light-years
  • Earth Similarity Index 0.806
  • Travel time at Voyager 1 speed 20,124,318 years
  • Almost certainly tidally locked to its host star given the close orbit

K2-47 b Planet Profile

Physical Specs

Radius
1.89 R⊕
Radius (Jupiter)
0.169 R♃
Mass
4.23 M⊕
Mass (Jupiter)
0.013 M♃
Density
3.44 g/cm³
Surface Gravity
1.18 g (Earth)

Classification

Planet Type

Super-Earth

ESI Score 0.806
HZ Position Inner
Controversial No

Discovery

Year 2016
Method Transit
Facility K2
Telescope 0.95 m Kepler Telescope

Size rank in cohort

Rank by radius

#143of 1176

top 12.1%

This planet

1.89R⊕

Super-Earth median

1.60R⊕

Nearest-size peers

Metric Earth K2-47 b Jupiter
Radius (R⊕)1.001.8911.21
Mass (M⊕)1.004.23317.83
Density (g/cm³)5.513.441.33
Surface Gravity (g)1.001.182.53
Insolation (S⊕)1.0010.700.037

Star Catalogue Identifiers

TIC

TIC 301603728

Gaia DR2

Gaia DR2 3811760011794444928

Gaia DR3

Gaia DR3 3811760011794444928

System

K2-47

Percentile among Super-Earth cohort

Radius 1.890 R⊕ · percentile 87 / cohort 1176
Mass 4.230 M⊕ · percentile 80 / cohort 1176
Orbital period 31.64 d · percentile 92 / cohort 1164
Distance 349.88 pc · percentile 36 / cohort 1171
ESI 0.806 · percentile 90 / cohort 1176

Orbit & Habitability

Orbital Dynamics

Period
31.637 days
Semi-major axis
0.1779 AU
Eccentricity
Inclination
°

Year Length

A year here lasts approximately 31.64 Earth days (8.7% of a terrestrial year) at a mean orbital distance of 0.1779 AU.

Transit Fingerprint

Depth

0.100 %

Duration

4.000 h

Impact parameter b

0.120

Rp / R★

0.022900

Transit midpoint (BJD)

2,456,825.7030

Photometric dip

Transit produces a flux drop of 999 ppm lasting ≈ 4.00 h.

Extended Orbital Architecture

Planet / star radius ratio

0.022900

Semi-major axis / stellar radius

46.800

Impact parameter (b)

0.120

Transit mid-time (BJD)

2,456,825.7030

Angular separation (arcsec)

0.50800

Eq. Temperature

 

Insolation (S⊕)

10.70

Earth = 1.00

Earth Similarity (ESI)

0.806

0 = alien, 1 = Earth-identical

Inside the inner HZ boundary (too hot for liquid water). Close-orbiting tidally-locked around a cool host.

Discovery Paper

Primary reference

Crossfield et al. 2016

Instrument

Kepler CCD Array

Publication

2016-09

Observation locale

Space

Host System: K2-47

Spectral Class

K-type orange

Effective Temperature

5,054 K — cooler than the Sun (5,778 K)

Estimated Age

Stellar Radius

0.760 R☉

Stellar Mass

0.750 M☉

Metallicity [Fe/H]

-0.22

Extended Stellar Properties

Surface gravity (log g)

4.544 dex

Stellar density

2.041 g/cm³

Metallicity ratio

[M/H]

Distance
349.88 parsec
Light-years 1,141.16 ly
V-band magnitude
14.07 mag
Voyager-speed travel 20,124,318 yr

Multi-band Host Photometry — 17 bands

8.916.516.49U14.98B14.07V13.74Gaia13.77Kepler13.16TESS15.15Sloan g15.30Sloan r15.51Sloan i13.58Sloan z12.30J11.86H11.74K11.70W111.76W211.74W38.90W4

Astrometric Data

Parallax

2.830 mas

Total Proper Motion

33.401 mas/yr

PM Right Ascension

-8.49 mas/yr

PM Declination

-32.30 mas/yr

Galactic Cartesian (pc)

x = -0.979 · y = 0.198 · z = 0.049

Equatorial (J2000)

RA 168.58257° · Dec 2.78056°

Galactic ℓ, b

255.104° · 56.351°

Ecliptic λ, β

168.411° · -1.957°

HTM-20 index

268809546

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