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 6.422 days
Semi-major axis 0.0665 AU
Distance from Earth 929.14 light-years
Earth Similarity Index 0.717
Travel time at Voyager 1 speed 16,385,386 years

1 sibling around K2-84

K2-84 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
K2-84 b this	Sub-Neptune	2.41	6.39	6.422	—	2016
K2-84 c	Sub-Neptune	2.03	4.78	27.860	—	2016

K2-84 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 0.717

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

#1312of 1978

top 66.3%

This planet

2.41R⊕

Sub-Neptune median

2.71R⊕

Nearest-size peers

Kepler-143 b 2.41 R⊕ Kepler-343 b 2.41 R⊕ GJ 536 b 2.41 R⊕

Metric	Earth	K2-84 b	Jupiter
Radius (R⊕)	1.00	2.41	11.21
Mass (M⊕)	1.00	6.39	317.83
Density (g/cm³)	5.51	2.51	1.33
Surface Gravity (g)	1.00	1.10	2.53
Insolation (S⊕)	1.00	178.00	0.037

Star Catalogue Identifiers

TIC

TIC 434133930

Gaia DR2

Gaia DR2 44062348664673152

Gaia DR3

Gaia DR3 44062348664673152

System

K2-84

Percentile among Sub-Neptune cohort

Radius 2.410 R⊕ · percentile 33 / cohort 1978

Mass 6.390 M⊕ · percentile 31 / cohort 1978

Orbital period 6.42 d · percentile 19 / cohort 1946

Distance 284.88 pc · percentile 34 / cohort 1975

ESI 0.717 · percentile 94 / cohort 1978

Orbit & Habitability

Orbital Dynamics

Period

6.422 days

Semi-major axis

0.0665 AU

Eccentricity

—

Inclination

— °

Year Length

A year here lasts approximately 6.42 Earth days (1.8% of a terrestrial year) at a mean orbital distance of 0.0665 AU.

Transit Fingerprint

Depth

0.081 %

Duration

2.810 h

Rp / R★

0.023400

Transit midpoint (BJD)

2,457,071.4212

Photometric dip

Transit produces a flux drop of 814 ppm lasting ≈ 2.81 h.

Extended Orbital Architecture

Planet / star radius ratio

0.023400

Semi-major axis / stellar radius

15.700

Transit mid-time (BJD)

2,457,071.4212

Angular separation (arcsec)

0.23300

Eq. Temperature

—

Insolation (S⊕)

178.00

Earth = 1.00

Earth Similarity (ESI)

0.717

0 = alien, 1 = Earth-identical

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: K2-84

Spectral Class

G-type yellow (Sun-like)

Effective Temperature

5,652 K — cooler than the Sun (5,778 K)

Estimated Age

—

Stellar Radius

0.930 R☉

Stellar Mass

0.950 M☉

Metallicity [Fe/H]

0.28

Extended Stellar Properties

Surface gravity (log g)

4.481 dex

Stellar density

2.291 g/cm³

Systemic radial velocity

7.64 km/s

Metallicity ratio

[M/H]

Distance

284.88 parsec

Light-years 929.14 ly

V-band magnitude

13.39 mag

Voyager-speed travel 16,385,386 yr

Multi-band Host Photometry — 17 bands

Astrometric Data

Parallax

3.482 mas

Total Proper Motion

33.117 mas/yr

PM Right Ascension

21.51 mas/yr

PM Declination

-25.19 mas/yr

Galactic Cartesian (pc)

x = 0.538 · y = 0.793 · z = 0.286

Equatorial (J2000)

RA 55.80936° · Dec 16.63444°

Galactic ℓ, b

171.581° · -29.580°

Ecliptic λ, β

57.368° · -3.016°

HTM-20 index

1791886602