Confirmed Exoplanet Discovered 2017

K2-126 b

A super-earth orbiting the k-type orange K2-126, located approximately 335.8 light-years from Earth.

Key parameters at a glance

  • A radius of 1.97 Earth radii
  • A mass of 4.54 Earth masses
  • Surface gravity around 1.17 g
  • An orbital period of 7.386 days
  • Semi-major axis 0.0656 AU
  • Equilibrium temperature 601 K (328 °C)
  • Distance from Earth 335.79 light-years
  • Earth Similarity Index 0.458
  • Travel time at Voyager 1 speed 5,921,610 years
  • Almost certainly tidally locked to its host star given the close orbit

K2-126 b Planet Profile

Physical Specs

Radius
1.97 R⊕
Radius (Jupiter)
0.176 R♃
Mass
4.54 M⊕
Mass (Jupiter)
0.014 M♃
Density
3.26 g/cm³
Surface Gravity
1.17 g (Earth)

Classification

Planet Type

Super-Earth

ESI Score 0.458
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

#38of 1176

top 3.1%

This planet

1.97R⊕

Super-Earth median

1.60R⊕

Nearest-size peers

Metric Earth K2-126 b Jupiter
Radius (R⊕)1.001.9711.21
Mass (M⊕)1.004.54317.83
Density (g/cm³)5.513.261.33
Surface Gravity (g)1.001.172.53
Insolation (S⊕)1.0035.300.037

Star Catalogue Identifiers

TIC

TIC 422349422

Gaia DR2

Gaia DR2 3606785098479012864

Gaia DR3

Gaia DR3 3606785098479012864

System

K2-126

Percentile among Super-Earth cohort

Radius 1.970 R⊕ · percentile 96 / cohort 1176
Mass 4.540 M⊕ · percentile 88 / cohort 1176
Orbital period 7.39 d · percentile 54 / cohort 1164
Distance 102.95 pc · percentile 17 / cohort 1171
ESI 0.458 · percentile 69 / cohort 1176

Orbit & Habitability

Orbital Dynamics

Period
7.386 days
Semi-major axis
0.0656 AU
Eccentricity
0.060
Inclination
89.40 °

Year Length

A year here lasts approximately 7.39 Earth days (2.0% of a terrestrial year) on a nearly circular orbit at a mean orbital distance of 0.0656 AU.

Transit Fingerprint

Depth

0.088 %

Duration

2.587 h

Impact parameter b

0.400

Rp / R★

0.027900

Transit midpoint (BJD)

2,457,223.7992

Photometric dip

Transit produces a flux drop of 882 ppm lasting ≈ 2.59 h.

Extended Orbital Architecture

Planet / star radius ratio

0.027900

Semi-major axis / stellar radius

20.290

Impact parameter (b)

0.400

Transit mid-time (BJD)

2,457,223.7992

Long. of periastron (ω)

-33.72°

Angular separation (arcsec)

0.63700

Eq. Temperature

601K

(328 °C)

Insolation (S⊕)

35.30

Earth = 1.00

Earth Similarity (ESI)

0.458

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

Dressing et al. 2017

Instrument

Kepler CCD Array

Publication

2017-11

Observation locale

Space

Host System: K2-126

Spectral Class

K-type orange

Effective Temperature

4,339 K — cooler than the Sun (5,778 K)

Estimated Age

Stellar Radius

0.650 R☉

Stellar Mass

0.690 M☉

Metallicity [Fe/H]

0.02

Extended Stellar Properties

Surface gravity (log g)

4.660 dex

Stellar density

2.903 g/cm³

Systemic radial velocity

1.00 km/s

Metallicity ratio

[Fe/H]

Distance
102.95 parsec
Light-years 335.79 ly
V-band magnitude
12.76 mag
Voyager-speed travel 5,921,610 yr

Multi-band Host Photometry — 12 bands

8.614.214.15B12.76V12.40Gaia12.45Kepler11.63TESS10.51J9.92H9.71K9.68W19.72W29.63W38.58W4

Astrometric Data

Parallax

9.685 mas

Total Proper Motion

37.050 mas/yr

PM Right Ascension

36.13 mas/yr

PM Declination

-8.21 mas/yr

Galactic Cartesian (pc)

x = -0.891 · y = -0.388 · z = -0.235

Equatorial (J2000)

RA 203.54670° · Dec -13.57697°

Galactic ℓ, b

318.559° · 47.993°

Ecliptic λ, β

206.772° · -3.492°

HTM-20 index

978186193

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