Confirmed Exoplanet Discovered 2021

K2-347 b

A sub-neptune orbiting the k-type orange K2-347, located approximately 1,044.8 light-years from Earth.

Key parameters at a glance

  • A radius of 2.41 Earth radii
  • A mass of 6.39 Earth masses
  • Surface gravity around 1.10 g
  • An orbital period of 7.187 days
  • Equilibrium temperature 640 K (367 °C)
  • Distance from Earth 1,044.80 light-years
  • Earth Similarity Index 0.401
  • Travel time at Voyager 1 speed 18,424,960 years
  • Almost certainly tidally locked to its host star given the close orbit

K2-347 b Planet Profile

Physical Specs

Radius
2.41 R⊕
Radius (Jupiter)
0.215 R♃
Mass
6.39 M⊕
Mass (Jupiter)
0.020 M♃
Density
2.51 g/cm³
Surface Gravity
1.10 g (Earth)

Classification

Planet Type

Sub-Neptune

ESI Score 0.401
HZ Position Unknown
Controversial No

Discovery

Year 2021
Method Transit
Facility K2
Telescope 0.95 m Kepler Telescope

Size rank in cohort

Rank by radius

#1312of 1978

top 66.3%

This planet

2.41R⊕

Sub-Neptune median

2.71R⊕

Nearest-size peers

Metric Earth K2-347 b Jupiter
Radius (R⊕)1.002.4111.21
Mass (M⊕)1.006.39317.83
Density (g/cm³)5.512.511.33
Surface Gravity (g)1.001.102.53
Insolation (S⊕)1.000.037

Star Catalogue Identifiers

TIC

TIC 14603874

Gaia DR2

Gaia DR2 678119333962115072

Gaia DR3

Gaia DR3 678119333962115072

System

K2-347

Percentile among Sub-Neptune cohort

Radius 2.410 R⊕ · percentile 33 / cohort 1978
Mass 6.390 M⊕ · percentile 31 / cohort 1978
Orbital period 7.19 d · percentile 23 / cohort 1946
Distance 320.34 pc · percentile 36 / cohort 1975
ESI 0.401 · percentile 53 / cohort 1978

Orbit & Habitability

Orbital Dynamics

Period
7.187 days
Semi-major axis
AU
Eccentricity
Inclination
°

Year Length

A year here lasts approximately 7.19 Earth days (2.0% of a terrestrial year).

Transit Fingerprint

Depth

0.183 %

Duration

2.570 h

Impact parameter b

0.210

Rp / R★

0.033500

Transit midpoint (BJD)

2,457,140.6993

Photometric dip

Transit produces a flux drop of 1,829 ppm lasting ≈ 2.57 h.

Extended Orbital Architecture

Planet / star radius ratio

0.033500

Semi-major axis / stellar radius

21.520

Impact parameter (b)

0.210

Transit mid-time (BJD)

2,457,140.6993

Eq. Temperature

640K

(367 °C)

Insolation (S⊕)

Earth = 1.00

Earth Similarity (ESI)

0.401

0 = alien, 1 = Earth-identical

Insufficient insolation data — the surface is too hot to retain surface water. Close-orbiting tidally-locked around a cool host.

Discovery Paper

Primary reference

De Leon et al. 2021

Instrument

Kepler CCD Array

Publication

2021-08

Observation locale

Space

Host System: K2-347

Spectral Class

K-type orange

Effective Temperature

4,599 K — cooler than the Sun (5,778 K)

Estimated Age

Stellar Radius

0.630 R☉

Stellar Mass

0.660 M☉

Metallicity [Fe/H]

-0.26

Extended Stellar Properties

Surface gravity (log g)

4.650 dex

Stellar density

4.122 g/cm³

Metallicity ratio

[Fe/H]

Distance
320.34 parsec
Light-years 1,044.80 ly
V-band magnitude
15.15 mag
Voyager-speed travel 18,424,960 yr

Multi-band Host Photometry — 17 bands

8.318.318.30U16.30B15.15V14.81Gaia14.78Kepler14.08TESS15.87Sloan g14.76Sloan r14.36Sloan i14.15Sloan z13.05J12.45H12.30K12.23W112.24W212.16W38.29W4

Astrometric Data

Parallax

3.093 mas

Total Proper Motion

52.548 mas/yr

PM Right Ascension

-52.11 mas/yr

PM Declination

6.75 mas/yr

Galactic Cartesian (pc)

x = -0.545 · y = 0.740 · z = 0.396

Equatorial (J2000)

RA 126.37268° · Dec 23.29741°

Galactic ℓ, b

200.549° · 30.428°

Ecliptic λ, β

123.087° · 3.939°

HTM-20 index

2005672191

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