Key parameters at a glance

A radius of 7.60 Earth radii
A mass of 44.90 Earth masses
Surface gravity around 0.78 g
An orbital period of 9.727 days
Semi-major axis 0.0940 AU
Equilibrium temperature 979 K (706 °C)
Distance from Earth 1,602.22 light-years
Earth Similarity Index 0.157
Travel time at Voyager 1 speed 28,255,064 years

K2-87 b Planet Profile

Physical Specs

Radius

7.60 R⊕

Radius (Jupiter)

0.678 R♃

Mass

44.90 M⊕

Mass (Jupiter)

0.141 M♃

Density

0.56 g/cm³

Surface Gravity

0.78 g (Earth)

Classification

Planet Type

Neptune-like

ESI Score 0.157

HZ Position Inner

Controversial No

Discovery

Year 2016

Method Transit

Facility K2

Telescope 0.95 m Kepler Telescope

Size rank in cohort

Rank by radius

#172of 574

top 29.8%

This planet

7.60R⊕

Neptune-like median

6.39R⊕

Nearest-size peers

55 Cnc f 7.59 R⊕ HD 134606 d 7.59 R⊕ OGLE-2018-BLG-0298L b 7.56 R⊕

Metric	Earth	K2-87 b	Jupiter
Radius (R⊕)	1.00	7.60	11.21
Mass (M⊕)	1.00	44.90	317.83
Density (g/cm³)	5.51	0.56	1.33
Surface Gravity (g)	1.00	0.78	2.53
Insolation (S⊕)	1.00	85.00	0.037

Star Catalogue Identifiers

TIC

TIC 17409453

Gaia DR2

Gaia DR2 47908509057301120

Gaia DR3

Gaia DR3 47908509057301120

System

K2-87

Percentile among Neptune-like cohort

Radius 7.600 R⊕ · percentile 70 / cohort 574

Mass 44.900 M⊕ · percentile 67 / cohort 574

Orbital period 9.73 d · percentile 36 / cohort 524

Distance 491.24 pc · percentile 56 / cohort 572

ESI 0.157 · percentile 16 / cohort 574

Orbit & Habitability

Orbital Dynamics

Period

9.727 days

Semi-major axis

0.0940 AU

Eccentricity

—

Inclination

87.74 °

Year Length

A year here lasts approximately 9.73 Earth days (2.7% of a terrestrial year) at a mean orbital distance of 0.0940 AU.

Transit Fingerprint

Depth

0.269 %

Duration

4.560 h

Impact parameter b

0.570

Rp / R★

0.050000

Transit midpoint (BJD)

2,457,072.3023

Photometric dip

Transit produces a flux drop of 2,692 ppm lasting ≈ 4.56 h.

Extended Orbital Architecture

Planet / star radius ratio

0.050000

Semi-major axis / stellar radius

14.400

Impact parameter (b)

0.570

Transit mid-time (BJD)

2,457,072.3023

Angular separation (arcsec)

0.19100

Eq. Temperature

979K

(706 °C)

Insolation (S⊕)

85.00

Earth = 1.00

Earth Similarity (ESI)

0.157

0 = alien, 1 = Earth-identical

Inside the inner HZ boundary (too hot for liquid water) — the surface is too hot to retain surface water.

Discovery Paper

Primary reference

Crossfield et al. 2016

Instrument

Kepler CCD Array

Publication

2016-09

Observation locale

Space

Discovery cohort

Planets confirmed in 2016 at K2 (12 shown).

K2-72 d · Rocky Terrestrial K2-72 b · Rocky Terrestrial K2-91 b · Rocky Terrestrial K2-72 c · Rocky Terrestrial K2-102 b · Super-Earth K2-90 c · Super-Earth K2-72 e · Super-Earth K2-83 b · Rocky Terrestrial K2-88 b · Rocky Terrestrial K2-80 c · Super-Earth K2-83 c · Super-Earth K2-65 b · Super-Earth

Host System: K2-87

Spectral Class

G-type yellow (Sun-like)

Effective Temperature

5,747 K — cooler than the Sun (5,778 K)

Estimated Age

—

Stellar Radius

1.401 R☉

Stellar Mass

1.164 M☉

Metallicity [Fe/H]

0.33

Extended Stellar Properties

Surface gravity (log g)

4.208 dex

Stellar density

0.590 g/cm³

Metallicity ratio

[Fe/H]

Distance

491.24 parsec

Light-years 1,602.22 ly

V-band magnitude

14.14 mag

Voyager-speed travel 28,255,064 yr

Multi-band Host Photometry — 17 bands

Astrometric Data

Parallax

2.007 mas

Total Proper Motion

29.331 mas/yr

PM Right Ascension

25.97 mas/yr

PM Declination

-13.64 mas/yr

Galactic Cartesian (pc)

x = 0.381 · y = 0.866 · z = 0.323

Equatorial (J2000)

RA 66.23636° · Dec 18.82736°

Galactic ℓ, b

177.290° · -20.816°

Ecliptic λ, β

67.548° · -2.779°

HTM-20 index

-1164731243