Confirmed Exoplanet Discovered 2015

K2-5 b

A super-earth orbiting the k-type orange K2-5, located approximately 661.9 light-years from Earth.

Key parameters at a glance

  • A radius of 1.91 Earth radii
  • A mass of 4.31 Earth masses
  • Surface gravity around 1.18 g
  • An orbital period of 5.736 days
  • Semi-major axis 0.0532 AU
  • Equilibrium temperature 565 K (292 °C)
  • Distance from Earth 661.91 light-years
  • Earth Similarity Index 0.490
  • Travel time at Voyager 1 speed 11,672,796 years
  • Almost certainly tidally locked to its host star given the close orbit

1 sibling around K2-5

K2-5 b shares its host star with 1 other confirmed planet. Side-by-side measurements below.

Planet Type Radius (R⊕) Mass (M⊕) Period (d) Eq. T (K) Year
K2-5 b this Super-Earth 1.91 4.31 5.736 565 2015
K2-5 c Sub-Neptune 2.26 5.73 10.932 456 2015

K2-5 b Planet Profile

Physical Specs

Radius
1.91 R⊕
Radius (Jupiter)
0.170 R♃
Mass
4.31 M⊕
Mass (Jupiter)
0.014 M♃
Density
3.40 g/cm³
Surface Gravity
1.18 g (Earth)

Classification

Planet Type

Super-Earth

ESI Score 0.490
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

#114of 1176

top 9.6%

This planet

1.91R⊕

Super-Earth median

1.60R⊕

Nearest-size peers

Metric Earth K2-5 b Jupiter
Radius (R⊕)1.001.9111.21
Mass (M⊕)1.004.31317.83
Density (g/cm³)5.513.401.33
Surface Gravity (g)1.001.182.53
Insolation (S⊕)1.0024.100.037

Star Catalogue Identifiers

TIC

TIC 38064757

Gaia DR2

Gaia DR2 3791512745687354496

Gaia DR3

Gaia DR3 3791512745687354496

System

K2-5

Percentile among Super-Earth cohort

Radius 1.910 R⊕ · percentile 90 / cohort 1176
Mass 4.310 M⊕ · percentile 83 / cohort 1176
Orbital period 5.74 d · percentile 45 / cohort 1164
Distance 202.94 pc · percentile 25 / cohort 1171
ESI 0.490 · percentile 72 / cohort 1176

Orbit & Habitability

Orbital Dynamics

Period
5.736 days
Semi-major axis
0.0532 AU
Eccentricity
Inclination
87.35 °

Year Length

A year here lasts approximately 5.74 Earth days (1.6% of a terrestrial year) at a mean orbital distance of 0.0532 AU.

Transit Fingerprint

Depth

0.150 %

Duration

2.654 h

Impact parameter b

0.650

Rp / R★

0.030310

Transit midpoint (BJD)

2,456,808.8600

Photometric dip

Transit produces a flux drop of 1,496 ppm lasting ≈ 2.65 h.

Extended Orbital Architecture

Planet / star radius ratio

0.030310

Semi-major axis / stellar radius

14.000

Impact parameter (b)

0.650

Transit mid-time (BJD)

2,456,808.8600

Angular separation (arcsec)

0.26200

Eq. Temperature

565K

(292 °C)

Insolation (S⊕)

24.10

Earth = 1.00

Earth Similarity (ESI)

0.490

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: K2-5

Spectral Class

K-type orange

Effective Temperature

3,930 K — cooler than the Sun (5,778 K)

Estimated Age

Stellar Radius

0.570 R☉

Stellar Mass

0.610 M☉

Metallicity [Fe/H]

-0.33

Extended Stellar Properties

Surface gravity (log g)

4.710 dex

Stellar density

4.405 g/cm³

Metallicity ratio

[Fe/H]

Distance
202.94 parsec
Light-years 661.91 ly
V-band magnitude
14.97 mag
Voyager-speed travel 11,672,796 yr

Multi-band Host Photometry — 17 bands

8.418.017.99U16.30B14.97V14.34Gaia14.36Kepler13.54TESS15.92Sloan g14.48Sloan r14.18Sloan i13.77Sloan z12.45J11.76H11.60K11.50W111.51W211.02W38.45W4

Astrometric Data

Parallax

4.899 mas

Total Proper Motion

35.111 mas/yr

PM Right Ascension

-11.07 mas/yr

PM Declination

33.32 mas/yr

Galactic Cartesian (pc)

x = -0.982 · y = 0.186 · z = -0.033

Equatorial (J2000)

RA 169.30346° · Dec -1.87783°

Galactic ℓ, b

261.144° · 53.173°

Ecliptic λ, β

170.904° · -5.961°

HTM-20 index

972305279

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