Confirmed Exoplanet Discovered 2021

K2-332 b

A sub-neptune orbiting the m-type red dwarf K2-332, located approximately 401.8 light-years from Earth.

Key parameters at a glance

  • A radius of 2.20 Earth radii
  • A mass of 5.48 Earth masses
  • Surface gravity around 1.13 g
  • An orbital period of 17.706 days
  • Equilibrium temperature 266 K (-7 °C)
  • Distance from Earth 401.83 light-years
  • Earth Similarity Index 0.762
  • Travel time at Voyager 1 speed 7,086,284 years
  • Almost certainly tidally locked to its host star given the close orbit

Context from the literature

K2-332 b is a potentially habitable Super-Earth or Mini-Neptune exoplanet with a radius of 2.2 earths. It is in the empirical habitable zone, receiving 1.17 times the light that Earth gets from the sun. Its star, K2-332, is type M4V, with a temperature of ~3300 K. It was detected using the transit method in 2016 and is 402 light-years away.

Excerpted from Wikipedia · full article

K2-332 b Planet Profile

Physical Specs

Radius
2.20 R⊕
Radius (Jupiter)
0.196 R♃
Mass
5.48 M⊕
Mass (Jupiter)
0.017 M♃
Density
2.83 g/cm³
Surface Gravity
1.13 g (Earth)

Classification

Planet Type

Sub-Neptune

ESI Score 0.762
HZ Position Unknown
Controversial No

Discovery

Year 2021
Method Transit
Facility K2
Telescope 0.95 m Kepler Telescope

Size rank in cohort

Rank by radius

#1673of 1978

top 84.5%

This planet

2.20R⊕

Sub-Neptune median

2.71R⊕

Nearest-size peers

Metric Earth K2-332 b Jupiter
Radius (R⊕)1.002.2011.21
Mass (M⊕)1.005.48317.83
Density (g/cm³)5.512.831.33
Surface Gravity (g)1.001.132.53
Insolation (S⊕)1.000.037

Star Catalogue Identifiers

TIC

TIC 330621494

Gaia DR2

Gaia DR2 607158571490718208

Gaia DR3

Gaia DR3 607158571490718208

System

K2-332

Percentile among Sub-Neptune cohort

Radius 2.200 R⊕ · percentile 15 / cohort 1978
Mass 5.480 M⊕ · percentile 15 / cohort 1978
Orbital period 17.71 d · percentile 58 / cohort 1946
Distance 123.20 pc · percentile 23 / cohort 1975
ESI 0.762 · percentile 98 / cohort 1978

Orbit & Habitability

Orbital Dynamics

Period
17.706 days
Semi-major axis
AU
Eccentricity
Inclination
°

Year Length

A year here lasts approximately 17.71 Earth days (4.8% of a terrestrial year).

Transit Fingerprint

Depth

0.677 %

Duration

2.030 h

Impact parameter b

0.390

Rp / R★

0.070700

Transit midpoint (BJD)

2,457,156.4207

Photometric dip

Transit produces a flux drop of 6,770 ppm lasting ≈ 2.03 h.

Extended Orbital Architecture

Planet / star radius ratio

0.070700

Semi-major axis / stellar radius

66.300

Impact parameter (b)

0.390

Transit mid-time (BJD)

2,457,156.4207

Eq. Temperature

266K

(-7 °C)

Insolation (S⊕)

Earth = 1.00

Earth Similarity (ESI)

0.762

0 = alien, 1 = Earth-identical

Insufficient insolation data — surface water would be frozen. Close-orbiting tidally-locked around a cool host.

Discovery Paper

Primary reference

De Leon et al. 2021

Instrument

Kepler CCD Array

Publication

2021-08

Observation locale

Space

Host System: K2-332

Spectral Class

M-type red dwarf

Effective Temperature

3,315 K — cooler than the Sun (5,778 K)

Estimated Age

Stellar Radius

0.280 R☉

Stellar Mass

0.270 M☉

Metallicity [Fe/H]

0.09

Extended Stellar Properties

Surface gravity (log g)

4.970 dex

Stellar density

15.363 g/cm³

Rotation period

31.71 days

Metallicity ratio

[Fe/H]

Distance
123.20 parsec
Light-years 401.83 ly
V-band magnitude
mag
Voyager-speed travel 7,086,284 yr

Multi-band Host Photometry — 16 bands

8.821.221.25U19.77B16.48Gaia15.77Kepler15.16TESS18.65Sloan g17.22Sloan r15.75Sloan i14.93Sloan z13.50J12.95H12.64K12.44W112.29W212.14W38.76W4

Astrometric Data

Parallax

8.089 mas

Total Proper Motion

18.782 mas/yr

PM Right Ascension

-15.42 mas/yr

PM Declination

-10.73 mas/yr

Galactic Cartesian (pc)

x = -0.696 · y = 0.675 · z = 0.246

Equatorial (J2000)

RA 135.88327° · Dec 14.25050°

Galactic ℓ, b

214.467° · 35.616°

Ecliptic λ, β

134.140° · -2.438°

HTM-20 index

947176015

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