Confirmed Exoplanet Discovered 2016

K2-71 b

A sub-neptune orbiting the k-type orange K2-71, located approximately 499.6 light-years from Earth.

Key parameters at a glance

  • A radius of 2.15 Earth radii
  • A mass of 5.27 Earth masses
  • Surface gravity around 1.14 g
  • An orbital period of 6.985 days
  • Semi-major axis 0.0559 AU
  • Distance from Earth 499.64 light-years
  • Earth Similarity Index 0.759
  • Travel time at Voyager 1 speed 8,811,237 years
  • Almost certainly tidally locked to its host star given the close orbit

K2-71 b Planet Profile

Physical Specs

Radius
2.15 R⊕
Radius (Jupiter)
0.192 R♃
Mass
5.27 M⊕
Mass (Jupiter)
0.017 M♃
Density
2.91 g/cm³
Surface Gravity
1.14 g (Earth)

Classification

Planet Type

Sub-Neptune

ESI Score 0.759
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

#1741of 1978

top 88.0%

This planet

2.15R⊕

Sub-Neptune median

2.71R⊕

Nearest-size peers

Metric Earth K2-71 b Jupiter
Radius (R⊕)1.002.1511.21
Mass (M⊕)1.005.27317.83
Density (g/cm³)5.512.911.33
Surface Gravity (g)1.001.142.53
Insolation (S⊕)1.0013.400.037

Star Catalogue Identifiers

TIC

TIC 402287746

Gaia DR2

Gaia DR2 2608279114251674624

Gaia DR3

Gaia DR3 2608279114251674624

System

K2-71

Percentile among Sub-Neptune cohort

Radius 2.150 R⊕ · percentile 11 / cohort 1978
Mass 5.270 M⊕ · percentile 12 / cohort 1978
Orbital period 6.99 d · percentile 22 / cohort 1946
Distance 153.19 pc · percentile 25 / cohort 1975
ESI 0.759 · percentile 98 / cohort 1978

Orbit & Habitability

Orbital Dynamics

Period
6.985 days
Semi-major axis
0.0559 AU
Eccentricity
Inclination
°

Year Length

A year here lasts approximately 6.99 Earth days (1.9% of a terrestrial year) at a mean orbital distance of 0.0559 AU.

Transit Fingerprint

Depth

0.291 %

Duration

1.410 h

Impact parameter b

0.880

Rp / R★

0.045700

Transit midpoint (BJD)

2,456,987.3785

Photometric dip

Transit produces a flux drop of 2,910 ppm lasting ≈ 1.41 h.

Extended Orbital Architecture

Planet / star radius ratio

0.045700

Impact parameter (b)

0.880

Transit mid-time (BJD)

2,456,987.3785

Angular separation (arcsec)

0.36500

Eq. Temperature

 

Insolation (S⊕)

13.40

Earth = 1.00

Earth Similarity (ESI)

0.759

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: K2-71

Spectral Class

K-type orange

Effective Temperature

4,006 K — cooler than the Sun (5,778 K)

Estimated Age

Stellar Radius

0.426 R☉

Stellar Mass

0.477 M☉

Metallicity [Fe/H]

Distance
153.19 parsec
Light-years 499.64 ly
V-band magnitude
16.14 mag
Voyager-speed travel 8,811,237 yr

Multi-band Host Photometry — 17 bands

8.819.619.62U18.12B16.14V15.19Gaia14.88Kepler14.02TESS16.99Sloan g15.58Sloan r14.46Sloan i13.85Sloan z12.60J11.93H11.73K11.57W111.52W211.58W38.78W4

Astrometric Data

Parallax

6.499 mas

Total Proper Motion

103.557 mas/yr

PM Right Ascension

103.56 mas/yr

PM Declination

0.59 mas/yr

Galactic Cartesian (pc)

x = 0.935 · y = -0.309 · z = -0.172

Equatorial (J2000)

RA 341.72487° · Dec -9.88161°

Galactic ℓ, b

57.398° · -55.970°

Ecliptic λ, β

339.392° · -1.981°

HTM-20 index

968583265

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