Confirmed Exoplanet Discovered 2015

K2-16 c

A sub-neptune orbiting the k-type orange K2-16, located approximately 1,092.5 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 19.079 days
  • Semi-major axis 0.1229 AU
  • Equilibrium temperature 485 K (212 °C)
  • Distance from Earth 1,092.51 light-years
  • Earth Similarity Index 0.507
  • Travel time at Voyager 1 speed 19,266,500 years
  • Almost certainly tidally locked to its host star given the close orbit

2 siblings around K2-16

K2-16 c shares its host star with 2 other confirmed planets. Side-by-side measurements below.

Planet Type Radius (R⊕) Mass (M⊕) Period (d) Eq. T (K) Year
EPIC 201754305 d Rocky Terrestrial 1.03 1.08 2.716 2019
K2-16 b Sub-Neptune 2.02 4.74 7.619 658 2015
K2-16 c this Sub-Neptune 2.54 6.99 19.079 485 2015

K2-16 c 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 0.507
HZ Position Inner
Controversial No

Discovery

Year 2015
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 K2-16 c 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⊕)1.0013.100.037

Star Catalogue Identifiers

TIC

TIC 281886199

Gaia DR2

Gaia DR2 3897048338487064064

Gaia DR3

Gaia DR3 3897048338487064064

System

K2-16

Percentile among Sub-Neptune cohort

Radius 2.540 R⊕ · percentile 43 / cohort 1978
Mass 6.990 M⊕ · percentile 40 / cohort 1978
Orbital period 19.08 d · percentile 60 / cohort 1946
Distance 334.97 pc · percentile 38 / cohort 1975
ESI 0.507 · percentile 71 / cohort 1978

Orbit & Habitability

Orbital Dynamics

Period
19.079 days
Semi-major axis
0.1229 AU
Eccentricity
Inclination
87.83 °

Year Length

A year here lasts approximately 19.08 Earth days (5.2% of a terrestrial year) at a mean orbital distance of 0.1229 AU.

Transit Fingerprint

Depth

0.107 %

Duration

3.859 h

Impact parameter b

0.860

Rp / R★

0.035260

Transit midpoint (BJD)

2,456,809.4800

Photometric dip

Transit produces a flux drop of 1,065 ppm lasting ≈ 3.86 h.

Extended Orbital Architecture

Planet / star radius ratio

0.035260

Semi-major axis / stellar radius

22.800

Impact parameter (b)

0.860

Transit mid-time (BJD)

2,456,809.4800

Angular separation (arcsec)

0.36700

Eq. Temperature

485K

(212 °C)

Insolation (S⊕)

13.10

Earth = 1.00

Earth Similarity (ESI)

0.507

0 = alien, 1 = Earth-identical

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

Discovery Paper

Primary reference

Montet et al. 2015

Instrument

Kepler CCD Array

Publication

2015-08

Observation locale

Space

Host System: K2-16

Spectral Class

K-type orange

Effective Temperature

4,742 K — cooler than the Sun (5,778 K)

Estimated Age

Stellar Radius

0.660 R☉

Stellar Mass

0.680 M☉

Metallicity [Fe/H]

-0.33

Extended Stellar Properties

Surface gravity (log g)

4.510 dex

Stellar density

2.960 g/cm³

Rotational v·sin i

2.00 km/s

Metallicity ratio

[Fe/H]

Distance
334.97 parsec
Light-years 1,092.51 ly
V-band magnitude
14.67 mag
Voyager-speed travel 19,266,500 yr

Multi-band Host Photometry — 12 bands

9.015.715.66B14.67V14.32Gaia14.30Kepler13.68TESS12.76J12.21H12.09K12.06W112.10W212.34W39.00W4

Astrometric Data

Parallax

2.957 mas

Total Proper Motion

22.566 mas/yr

PM Right Ascension

-6.38 mas/yr

PM Declination

21.65 mas/yr

Galactic Cartesian (pc)

x = -0.993 · y = 0.085 · z = 0.079

Equatorial (J2000)

RA 175.09722° · Dec 4.55743°

Galactic ℓ, b

262.912° · 61.777°

Ecliptic λ, β

173.689° · 2.236°

HTM-20 index

1035328883

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