Key parameters at a glance

A radius of 2.17 Earth radii
A mass of 5.35 Earth masses
Surface gravity around 1.14 g
An orbital period of 11.542 days
Semi-major axis 0.1087 AU
Equilibrium temperature 1,035 K (762 °C)
Distance from Earth 870.39 light-years
Earth Similarity Index 0.254
Travel time at Voyager 1 speed 15,349,379 years

1 sibling around K2-243

K2-243 b shares its host star with 1 other confirmed planet. Side-by-side measurements below.

Planet	Type	Radius (R⊕)	Mass (M⊕)	Period (d)	Eq. T (K)	Year
K2-243 b this	Sub-Neptune	2.17	5.35	11.542	1,035	2018
K2-243 c	Sub-Neptune	2.01	4.70	24.946	801	2018

K2-243 b Planet Profile

Physical Specs

Radius

2.17 R⊕

Radius (Jupiter)

0.194 R♃

Mass

5.35 M⊕

Mass (Jupiter)

0.017 M♃

Density

2.88 g/cm³

Surface Gravity

1.14 g (Earth)

Classification

Planet Type

Sub-Neptune

ESI Score 0.254

HZ Position Unknown

Controversial No

Discovery

Year 2018

Method Transit

Facility K2

Telescope 0.95 m Kepler Telescope

Size rank in cohort

Rank by radius

#1720of 1978

top 86.9%

This planet

2.17R⊕

Sub-Neptune median

2.71R⊕

Nearest-size peers

Kepler-1329 b 2.17 R⊕ Kepler-797 b 2.17 R⊕ Kepler-304 c 2.17 R⊕

Metric	Earth	K2-243 b	Jupiter
Radius (R⊕)	1.00	2.17	11.21
Mass (M⊕)	1.00	5.35	317.83
Density (g/cm³)	5.51	2.88	1.33
Surface Gravity (g)	1.00	1.14	2.53
Insolation (S⊕)	1.00	—	0.037

Star Catalogue Identifiers

TIC

TIC 96199085

Gaia DR2

Gaia DR2 3597570989175080576

Gaia DR3

Gaia DR3 3597570989175080576

System

K2-243

Percentile among Sub-Neptune cohort

Radius 2.170 R⊕ · percentile 13 / cohort 1978

Mass 5.350 M⊕ · percentile 13 / cohort 1978

Orbital period 11.54 d · percentile 40 / cohort 1946

Distance 266.86 pc · percentile 33 / cohort 1975

ESI 0.254 · percentile 17 / cohort 1978

Orbit & Habitability

Orbital Dynamics

Period

11.542 days

Semi-major axis

0.1087 AU

Eccentricity

—

Inclination

— °

Year Length

A year here lasts approximately 11.54 Earth days (3.2% of a terrestrial year) at a mean orbital distance of 0.1087 AU.

Transit Fingerprint

Depth

0.016 %

Duration

3.700 h

Impact parameter b

0.390

Rp / R★

0.014400

Transit midpoint (BJD)

2,457,593.2062

Photometric dip

Transit produces a flux drop of 160 ppm lasting ≈ 3.70 h.

Extended Orbital Architecture

Planet / star radius ratio

0.014400

Semi-major axis / stellar radius

21.200

Impact parameter (b)

0.390

Transit mid-time (BJD)

2,457,593.2062

Angular separation (arcsec)

0.40700

Eq. Temperature

1,035K

(762 °C)

Insolation (S⊕)

—

Earth = 1.00

Earth Similarity (ESI)

0.254

0 = alien, 1 = Earth-identical

Insufficient insolation data — the dayside is scorched.

Discovery Paper

Primary reference

Livingston et al. 2018

Instrument

Kepler CCD Array

Publication

2018-08

Observation locale

Space

Discovery cohort

Planets confirmed in 2018 at K2 (12 shown).

K2-190 c · Rocky Terrestrial K2-183 b · Rocky Terrestrial K2-209 b · Rocky Terrestrial K2-210 b · Rocky Terrestrial K2-165 b · Super-Earth K2-169 b · Super-Earth K2-148 b · Super-Earth K2-219 b · Super-Earth K2-190 b · Super-Earth K2-200 b · Super-Earth K2-201 b · Super-Earth K2-170 b · Super-Earth

Host System: K2-243

Spectral Class

F-type yellow-white

Effective Temperature

6,570 K — hotter than the Sun (5,778 K)

Estimated Age

—

Stellar Radius

1.390 R☉

Stellar Mass

1.290 M☉

Metallicity [Fe/H]

-0.03

Extended Stellar Properties

Surface gravity (log g)

4.260 dex

Stellar density

0.352 g/cm³

Systemic radial velocity

5.79 km/s

Metallicity ratio

[Fe/H]

Distance

266.86 parsec

Light-years 870.39 ly

V-band magnitude

10.97 mag

Voyager-speed travel 15,349,379 yr

Multi-band Host Photometry — 12 bands

Astrometric Data

Parallax

3.719 mas

Total Proper Motion

64.447 mas/yr

PM Right Ascension

-61.81 mas/yr

PM Declination

18.24 mas/yr

Galactic Cartesian (pc)

x = -0.996 · y = -0.019 · z = -0.085

Equatorial (J2000)

RA 181.12114° · Dec -4.89914°

Galactic ℓ, b

281.666° · 56.022°

Ecliptic λ, β

182.976° · -4.048°

HTM-20 index

-1970276540