Key parameters at a glance

A radius of 2.93 Earth radii
A mass of 8.91 Earth masses
Surface gravity around 1.04 g
An orbital period of 6.220 days
Semi-major axis 0.0542 AU
Equilibrium temperature 432 K (159 °C)
Distance from Earth 574.98 light-years
Earth Similarity Index 0.529
Travel time at Voyager 1 speed 10,139,837 years
Almost certainly tidally locked to its host star given the close orbit

K2-317 b Planet Profile

Physical Specs

Radius

2.93 R⊕

Radius (Jupiter)

0.261 R♃

Mass

8.91 M⊕

Mass (Jupiter)

0.028 M♃

Density

1.95 g/cm³

Surface Gravity

1.04 g (Earth)

Classification

Planet Type

Sub-Neptune

ESI Score 0.529

HZ Position Unknown

Controversial No

Discovery

Year 2020

Method Transit

Facility K2

Telescope 0.95 m Kepler Telescope

Size rank in cohort

Rank by radius

#585of 1978

top 29.5%

This planet

2.93R⊕

Sub-Neptune median

2.71R⊕

Nearest-size peers

TOI-125 d 2.93 R⊕ Kepler-221 c 2.93 R⊕ TOI-2015 c 2.93 R⊕

Metric	Earth	K2-317 b	Jupiter
Radius (R⊕)	1.00	2.93	11.21
Mass (M⊕)	1.00	8.91	317.83
Density (g/cm³)	5.51	1.95	1.33
Surface Gravity (g)	1.00	1.04	2.53
Insolation (S⊕)	1.00	—	0.037

Star Catalogue Identifiers

TIC

TIC 70412892

Gaia DR2

Gaia DR2 6255655673768103168

Gaia DR3

Gaia DR3 6255655673768103168

System

K2-317

Percentile among Sub-Neptune cohort

Radius 2.930 R⊕ · percentile 70 / cohort 1978

Mass 8.910 M⊕ · percentile 64 / cohort 1978

Orbital period 6.22 d · percentile 18 / cohort 1946

Distance 176.29 pc · percentile 27 / cohort 1975

ESI 0.529 · percentile 74 / cohort 1978

Orbit & Habitability

Orbital Dynamics

Period

6.220 days

Semi-major axis

0.0542 AU

Eccentricity

—

Inclination

89.22 °

Year Length

A year here lasts approximately 6.22 Earth days (1.7% of a terrestrial year) at a mean orbital distance of 0.0542 AU.

Transit Fingerprint

Depth

0.119 %

Impact parameter b

0.430

Transit midpoint (BJD)

2,457,994.1320

Photometric dip

Transit produces a flux drop of 1,190 ppm.

Eq. Temperature

432K

(159 °C)

Insolation (S⊕)

—

Earth = 1.00

Earth Similarity (ESI)

0.529

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

Castro Gonz Aacute Lez et al. 2020

Instrument

Kepler CCD Array

Publication

2020-12

Observation locale

Space

Discovery cohort

Planets confirmed in 2020 at K2 (12 shown).

EPIC 201170410.02 · Rocky Terrestrial EPIC 201757695.02 · Rocky Terrestrial K2-323 b · Sub-Neptune K2-315 b · Rocky Terrestrial K2-316 c · Super-Earth K2-318 b · Super-Earth K2-325 b · Sub-Neptune K2-322 b · Super-Earth K2-319 b · Sub-Neptune K2-316 b · Super-Earth K2-324 b · Sub-Neptune K2-320 b · Sub-Neptune

Host System: K2-317

Spectral Class

M-type red dwarf

Effective Temperature

3,387 K — cooler than the Sun (5,778 K)

Estimated Age

—

Stellar Radius

0.379 R☉

Stellar Mass

0.403 M☉

Metallicity [Fe/H]

—

Distance

176.29 parsec

Light-years 574.98 ly

V-band magnitude

17.74 mag

Voyager-speed travel 10,139,837 yr

Multi-band Host Photometry — 12 bands

Astrometric Data

Parallax

5.647 mas

Total Proper Motion

60.932 mas/yr

PM Right Ascension

-48.40 mas/yr

PM Declination

-37.02 mas/yr

Galactic Cartesian (pc)

x = -0.617 · y = -0.700 · z = -0.359

Equatorial (J2000)

RA 228.61886° · Dec -21.02272°

Galactic ℓ, b

342.307° · 30.701°

Ecliptic λ, β

231.837° · -2.897°

HTM-20 index

-1700574585