Confirmed Exoplanet Discovered 2018

EPIC 211945201 b

A neptune-like orbiting the g-type yellow (sun-like) EPIC 211945201, located approximately 592.6 light-years from Earth.

Key parameters at a glance

  • A radius of 5.76 Earth radii
  • A mass of 11.00 Earth masses
  • Surface gravity around 0.33 g
  • An orbital period of 19.492 days
  • Semi-major axis 0.1493 AU
  • Equilibrium temperature 817 K (544 °C)
  • Distance from Earth 592.59 light-years
  • Earth Similarity Index 0.183
  • Travel time at Voyager 1 speed 10,450,374 years

EPIC 211945201 b Planet Profile

Physical Specs

Radius
5.76 R⊕
Radius (Jupiter)
0.514 R♃
Mass
11.00 M⊕
Mass (Jupiter)
0.035 M♃
Density
0.33 g/cm³
Surface Gravity
0.33 g (Earth)

Classification

Planet Type

Neptune-like

ESI Score 0.183
HZ Position Inner
Controversial No

Discovery

Year 2018
Method Transit
Facility K2
Telescope 0.95 m Kepler Telescope

Size rank in cohort

Rank by radius

#302of 574

top 52.4%

This planet

5.76R⊕

Neptune-like median

6.39R⊕

Nearest-size peers

Metric Earth EPIC 211945201 b Jupiter
Radius (R⊕)1.005.7611.21
Mass (M⊕)1.0011.00317.83
Density (g/cm³)5.510.331.33
Surface Gravity (g)1.000.332.53
Insolation (S⊕)1.00101.000.037

Alternative Mass Estimates

Method Value Interpretation
Best measured mass 11.000 M⊕ Direct mass measurement (not derived).

Star Catalogue Identifiers

TIC

TIC 243244680

Gaia DR2

Gaia DR2 636363799347569408

Gaia DR3

Gaia DR3 636363799347569408

System

EPIC 211945201

Percentile among Neptune-like cohort

Radius 5.760 R⊕ · percentile 47 / cohort 574
Mass 11.000 M⊕ · percentile 4 / cohort 574
Orbital period 19.49 d · percentile 51 / cohort 524
Distance 181.69 pc · percentile 37 / cohort 572
ESI 0.183 · percentile 24 / cohort 574

Orbit & Habitability

Orbital Dynamics

Period
19.492 days
Semi-major axis
0.1493 AU
Eccentricity
0.000
Inclination
87.90 °

Year Length

A year here lasts approximately 19.49 Earth days (5.3% of a terrestrial year) on a nearly circular orbit at a mean orbital distance of 0.1493 AU.

Transit Fingerprint

Depth

0.170 %

Duration

3.910 h

Impact parameter b

0.580

Rp / R★

0.037900

Transit midpoint (BJD)

2,457,158.8248

Photometric dip

Transit produces a flux drop of 1,700 ppm lasting ≈ 3.91 h.

Extended Orbital Architecture

Planet / star radius ratio

0.037900

Semi-major axis / stellar radius

35.630

Impact parameter (b)

0.580

RV semi-amplitude (K)

5.700 m/s

Transit mid-time (BJD)

2,457,158.8248

Long. of periastron (ω)

90.00°

Angular separation (arcsec)

0.82200

Eq. Temperature

817K

(544 °C)

Insolation (S⊕)

101.00

Earth = 1.00

Earth Similarity (ESI)

0.183

0 = alien, 1 = Earth-identical

Inside the inner HZ boundary (too hot for liquid water) — the surface is too hot to retain surface water.

Detection Signatures

Transit photometry

A transit dip has been observed from at least one telescope.

Radial velocity

Stellar wobble has been measured spectroscopically.

Discovery Paper

Primary reference

Chakraborty et al. 2018

Instrument

Kepler CCD Array

Publication

2018-07

Observation locale

Space

Host System: EPIC 211945201

Spectral Class

G-type yellow (Sun-like)

Effective Temperature

6,069 K — hotter than the Sun (5,778 K)

Estimated Age

3.99 Gyr — younger than the Sun (4.6 Gyr)

Stellar Radius

1.390 R☉

Stellar Mass

1.170 M☉

Metallicity [Fe/H]

0.10

Extended Stellar Properties

Surface gravity (log g)

4.220 dex

Stellar density

2.253 g/cm³

Systemic radial velocity

1.26 km/s

Rotational v·sin i

0.10 km/s

Activity index (log R'HK)

-5.193

Metallicity ratio

[Fe/H]

Distance
181.69 parsec
Light-years 592.59 ly
V-band magnitude
10.15 mag
Voyager-speed travel 10,450,374 yr

Multi-band Host Photometry — 12 bands

8.610.910.94B10.15V10.05Gaia10.12Kepler9.67TESS9.14J8.91H8.84K8.82W18.84W28.81W38.62W4

Astrometric Data

Parallax

5.475 mas

Total Proper Motion

61.773 mas/yr

PM Right Ascension

45.49 mas/yr

PM Declination

-41.79 mas/yr

Galactic Cartesian (pc)

x = -0.685 · y = 0.648 · z = 0.332

Equatorial (J2000)

RA 136.57419° · Dec 19.40206°

Galactic ℓ, b

208.782° · 38.128°

Ecliptic λ, β

133.293° · 2.687°

HTM-20 index

-1520383070

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