Confirmed Exoplanet Discovered 2016

K2-32 b

A neptune-like orbiting the g-type yellow (sun-like) K2-32, located approximately 514.3 light-years from Earth.

Key parameters at a glance

  • A radius of 5.30 Earth radii
  • A mass of 15.00 Earth masses
  • Surface gravity around 0.53 g
  • An orbital period of 8.992 days
  • Semi-major axis 0.0795 AU
  • Equilibrium temperature 837 K (564 °C)
  • Distance from Earth 514.29 light-years
  • Earth Similarity Index 0.201
  • Travel time at Voyager 1 speed 9,069,491 years

3 siblings around K2-32

K2-32 b shares its host star with 3 other confirmed planets. Side-by-side measurements below.

Planet Type Radius (R⊕) Mass (M⊕) Period (d) Eq. T (K) Year
K2-32 e Rocky Terrestrial 1.21 2.10 4.349 1,066 2019
K2-32 b this Neptune-like 5.30 15.00 8.992 837 2016
K2-32 c Sub-Neptune 3.13 8.10 20.661 634 2016
K2-32 d Sub-Neptune 3.48 6.70 31.717 550 2016

K2-32 b Planet Profile

Physical Specs

Radius
5.30 R⊕
Radius (Jupiter)
0.473 R♃
Mass
15.00 M⊕
Mass (Jupiter)
0.047 M♃
Density
0.55 g/cm³
Surface Gravity
0.53 g (Earth)

Classification

Planet Type

Neptune-like

ESI Score 0.201
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

#345of 574

top 59.9%

This planet

5.30R⊕

Neptune-like median

6.39R⊕

Nearest-size peers

Metric Earth K2-32 b Jupiter
Radius (R⊕)1.005.3011.21
Mass (M⊕)1.0015.00317.83
Density (g/cm³)5.510.551.33
Surface Gravity (g)1.000.532.53
Insolation (S⊕)1.0079.500.037

Alternative Mass Estimates

Method Value Interpretation
Best measured mass 15.000 M⊕ Direct mass measurement (not derived).

Star Catalogue Identifiers

TIC

TIC 437444661

Gaia DR2

Gaia DR2 4130539180358512768

Gaia DR3

Gaia DR3 4130539180358512768

System

K2-32

Percentile among Neptune-like cohort

Radius 5.299 R⊕ · percentile 40 / cohort 574
Mass 15.000 M⊕ · percentile 6 / cohort 574
Orbital period 8.99 d · percentile 35 / cohort 524
Distance 157.68 pc · percentile 34 / cohort 572
ESI 0.201 · percentile 28 / cohort 574

Orbit & Habitability

Orbital Dynamics

Period
8.992 days
Semi-major axis
0.0795 AU
Eccentricity
0.030
Inclination
89.00 °

Year Length

A year here lasts approximately 8.99 Earth days (2.5% of a terrestrial year) on a nearly circular orbit at a mean orbital distance of 0.0795 AU.

Transit Fingerprint

Depth

0.380 %

Duration

3.488 h

Impact parameter b

0.340

Rp / R★

0.056420

Transit midpoint (BJD)

2,456,900.9268

Photometric dip

Transit produces a flux drop of 3,802 ppm lasting ≈ 3.49 h.

Extended Orbital Architecture

Planet / star radius ratio

0.056420

Semi-major axis / stellar radius

19.860

Impact parameter (b)

0.340

RV semi-amplitude (K)

5.220 m/s

Transit mid-time (BJD)

2,456,900.9268

Long. of periastron (ω)

220.00°

Angular separation (arcsec)

0.50400

Eq. Temperature

837K

(564 °C)

Insolation (S⊕)

79.50

Earth = 1.00

Earth Similarity (ESI)

0.201

0 = alien, 1 = Earth-identical

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

Detection Signatures

Transit photometry

A transit dip has been observed from at least one telescope.

Radial velocity

Stellar wobble has been measured spectroscopically.

Discovery Paper

Primary reference

Dai et al. 2016

Instrument

Kepler CCD Array

Publication

2016-06

Observation locale

Space

Host System: K2-32

Spectral Class

G-type yellow (Sun-like)

Effective Temperature

5,271 K — cooler than the Sun (5,778 K)

Estimated Age

7.90 Gyr — older than the Sun (4.6 Gyr)

Stellar Radius

0.860 R☉

Stellar Mass

0.830 M☉

Metallicity [Fe/H]

-0.06

Extended Stellar Properties

Surface gravity (log g)

4.490 dex

Stellar density

1.833 g/cm³

Systemic radial velocity

-2.20 km/s

Rotational v·sin i

0.70 km/s

Activity index (log R'HK)

-5.061

Metallicity ratio

[Fe/H]

Distance
157.68 parsec
Light-years 514.29 ly
V-band magnitude
12.30 mag
Voyager-speed travel 9,069,491 yr

Multi-band Host Photometry — 12 bands

8.413.313.27B12.30V12.00Gaia12.01Kepler11.37TESS10.40J9.99H9.82K9.75W19.79W29.89W38.41W4

Astrometric Data

Parallax

6.314 mas

Total Proper Motion

56.149 mas/yr

PM Right Ascension

-16.60 mas/yr

PM Declination

-53.64 mas/yr

Galactic Cartesian (pc)

x = -0.285 · y = -0.898 · z = -0.335

Equatorial (J2000)

RA 252.42601° · Dec -19.54305°

Galactic ℓ, b

0.546° · 15.802°

Ecliptic λ, β

253.443° · 2.892°

HTM-20 index

1677871432

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