Key parameters at a glance

A radius of 2.69 Earth radii
A mass of 7.69 Earth masses
Surface gravity around 1.07 g
An orbital period of 5.628 days
Distance from Earth 1,976.92 light-years
Earth Similarity Index 0.678
Travel time at Voyager 1 speed 34,863,032 years

K2-171 b Planet Profile

Physical Specs

Radius

2.69 R⊕

Radius (Jupiter)

0.240 R♃

Mass

7.69 M⊕

Mass (Jupiter)

0.024 M♃

Density

2.18 g/cm³

Surface Gravity

1.07 g (Earth)

Classification

Planet Type

Sub-Neptune

ESI Score 0.678

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

#894of 1978

top 45.1%

This planet

2.69R⊕

Sub-Neptune median

2.71R⊕

Nearest-size peers

Kepler-1772 b 2.69 R⊕ HD 28109 b 2.69 R⊕ Kepler-417 c 2.69 R⊕

Metric	Earth	K2-171 b	Jupiter
Radius (R⊕)	1.00	2.69	11.21
Mass (M⊕)	1.00	7.69	317.83
Density (g/cm³)	5.51	2.18	1.33
Surface Gravity (g)	1.00	1.07	2.53
Insolation (S⊕)	1.00	—	0.037

Star Catalogue Identifiers

TIC

TIC 206241306

Gaia DR2

Gaia DR2 2612301329648852224

Gaia DR3

Gaia DR3 2612301329648852224

System

K2-171

Percentile among Sub-Neptune cohort

Radius 2.687 R⊕ · percentile 55 / cohort 1978

Mass 7.690 M⊕ · percentile 51 / cohort 1978

Orbital period 5.63 d · percentile 15 / cohort 1946

Distance 606.13 pc · percentile 53 / cohort 1975

ESI 0.678 · percentile 90 / cohort 1978

Orbit & Habitability

Orbital Dynamics

Period

5.628 days

Semi-major axis

— AU

Eccentricity

—

Inclination

85.05 °

Year Length

A year here lasts approximately 5.63 Earth days (1.5% of a terrestrial year).

Transit Fingerprint

Depth

0.022 %

Duration

8.208 h

Impact parameter b

0.540

Rp / R★

0.014341

Transit midpoint (BJD)

2,456,979.4671

Photometric dip

Transit produces a flux drop of 219 ppm lasting ≈ 8.21 h.

Extended Orbital Architecture

Planet / star radius ratio

0.014341

Semi-major axis / stellar radius

5.470

Impact parameter (b)

0.540

Transit mid-time (BJD)

2,456,979.4671

Eq. Temperature

—

Insolation (S⊕)

—

Earth = 1.00

Earth Similarity (ESI)

0.678

0 = alien, 1 = Earth-identical

Discovery Paper

Primary reference

Mayo et al. 2018

Instrument

Kepler CCD Array

Publication

2018-03

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: K2-171

Spectral Class

G-type yellow (Sun-like)

Effective Temperature

5,250 K — cooler than the Sun (5,778 K)

Estimated Age

—

Stellar Radius

1.717 R☉

Stellar Mass

0.892 M☉

Metallicity [Fe/H]

-0.09

Extended Stellar Properties

Surface gravity (log g)

3.950 dex

Systemic radial velocity

-9.97 km/s

Metallicity ratio

[Fe/H]

Distance

606.13 parsec

Light-years 1,976.92 ly

V-band magnitude

12.75 mag

Voyager-speed travel 34,863,032 yr

Multi-band Host Photometry — 12 bands

Astrometric Data

Parallax

1.622 mas

Total Proper Motion

9.063 mas/yr

PM Right Ascension

-8.95 mas/yr

PM Declination

1.45 mas/yr

Galactic Cartesian (pc)

x = 0.862 · y = -0.452 · z = -0.232

Equatorial (J2000)

RA 332.34077° · Dec -13.42886°

Galactic ℓ, b

44.597° · -49.815°

Ecliptic λ, β

329.537° · -1.918°

HTM-20 index

1760464386