Confirmed Exoplanet Discovered 2018

EPIC 246851721 b

A gas giant orbiting the f-type yellow-white EPIC 246851721, located approximately 1,215.4 light-years from Earth.

Key parameters at a glance

  • A radius of 11.78 Earth radii
  • A mass of 953.49 Earth masses
  • Surface gravity around 6.87 g
  • An orbital period of 6.180 days
  • Semi-major axis 0.0723 AU
  • Equilibrium temperature 1,401 K (1128 °C)
  • Distance from Earth 1,215.36 light-years
  • Earth Similarity Index 0.118
  • Travel time at Voyager 1 speed 21,432,901 years

EPIC 246851721 b Planet Profile

Physical Specs

Radius
11.78 R⊕
Radius (Jupiter)
1.051 R♃
Mass
953.49 M⊕
Mass (Jupiter)
3.000 M♃
Density
3.10 g/cm³
Surface Gravity
6.87 g (Earth)

Classification

Planet Type

Gas Giant

ESI Score 0.118
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

#1560of 1771

top 88.0%

This planet

11.78R⊕

Gas Giant median

13.52R⊕

Nearest-size peers

Metric Earth EPIC 246851721 b Jupiter
Radius (R⊕)1.0011.7811.21
Mass (M⊕)1.00953.49317.83
Density (g/cm³)5.513.101.33
Surface Gravity (g)1.006.872.53
Insolation (S⊕)1.00642.000.037

Alternative Mass Estimates

Method Value Interpretation
Best measured mass 953.490 M⊕ Direct mass measurement (not derived).
Minimum mass (M sin i) 953.490 M⊕ Lower bound from radial-velocity fitting.
Computed mass 955.580 M⊕ Model-computed mass (e.g. from mass-radius relation).

Star Catalogue Identifiers

TIC

TIC 411839167

Gaia DR2

Gaia DR2 3393939026234131584

Gaia DR3

Gaia DR3 3393939030531019520

System

EPIC 246851721

Percentile among Gas Giant cohort

Radius 11.781 R⊕ · percentile 12 / cohort 1771
Mass 953.490 M⊕ · percentile 66 / cohort 1747
Orbital period 6.18 d · percentile 40 / cohort 1533
Distance 372.63 pc · percentile 67 / cohort 1759
ESI 0.118 · percentile 31 / cohort 1771

Orbit & Habitability

Orbital Dynamics

Period
6.180 days
Semi-major axis
0.0723 AU
Eccentricity
Inclination
86.21 °

Year Length

A year here lasts approximately 6.18 Earth days (1.7% of a terrestrial year) at a mean orbital distance of 0.0723 AU.

Transit Fingerprint

Depth

0.464 %

Duration

4.108 h

Impact parameter b

0.647

Rp / R★

0.068100

Transit midpoint (BJD)

2,457,865.1103

Photometric dip

Transit produces a flux drop of 4,640 ppm lasting ≈ 4.11 h.

Extended Orbital Architecture

Planet / star radius ratio

0.068100

Semi-major axis / stellar radius

9.800

Impact parameter (b)

0.647

RV semi-amplitude (K)

270.000 m/s

Transit mid-time (BJD)

2,457,865.1103

Sky-projected obliquity (λ)

-1.47°

True obliquity (ψ)

3.70°

Angular separation (arcsec)

0.19400

Eq. Temperature

1,401K

(1128 °C)

Insolation (S⊕)

642.00

Earth = 1.00

Earth Similarity (ESI)

0.118

0 = alien, 1 = Earth-identical

Inside the inner HZ boundary (too hot for liquid water) — the dayside is scorched.

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

Yu et al. 2018

Instrument

Kepler CCD Array

Publication

2018-12

Observation locale

Space

Host System: EPIC 246851721

Spectral Class

F-type yellow-white

Effective Temperature

6,202 K — hotter than the Sun (5,778 K)

Estimated Age

3.02 Gyr — younger than the Sun (4.6 Gyr)

Stellar Radius

1.586 R☉

Stellar Mass

1.317 M☉

Metallicity [Fe/H]

0.14

Extended Stellar Properties

Surface gravity (log g)

4.157 dex

Stellar density

0.465 g/cm³

Systemic radial velocity

36.85 km/s

Rotational v·sin i

74.92 km/s

Metallicity ratio

[Fe/H]

Distance
372.63 parsec
Light-years 1,215.36 ly
V-band magnitude
11.24 mag
Voyager-speed travel 21,432,901 yr

Multi-band Host Photometry — 17 bands

8.615.315.26U12.07B11.24V11.25Gaia11.26Kepler10.82TESS11.73Sloan g11.31Sloan r11.18Sloan i11.33Sloan z10.20J9.97H9.89K9.81W19.82W29.75W38.61W4

Astrometric Data

Parallax

2.664 mas

Total Proper Motion

13.264 mas/yr

PM Right Ascension

2.72 mas/yr

PM Declination

-12.98 mas/yr

Galactic Cartesian (pc)

x = 0.184 · y = 0.942 · z = 0.280

Equatorial (J2000)

RA 78.91982° · Dec 16.27870°

Galactic ℓ, b

186.975° · -12.641°

Ecliptic λ, β

79.290° · -6.750°

HTM-20 index

-1297712520

Similar Worlds

Explore Related Categories