Confirmed Exoplanet Discovered 2021

KOI-1831 d

A rocky terrestrial orbiting the g-type yellow (sun-like) Kepler-324, located approximately 1,635.9 light-years from Earth.

Key parameters at a glance

  • A radius of 1.13 Earth radii
  • A mass of 2.23 Earth masses
  • Surface gravity around 1.75 g
  • An orbital period of 34.169 days
  • Semi-major axis 0.1992 AU
  • Equilibrium temperature 475 K (202 °C)
  • Distance from Earth 1,635.91 light-years
  • Earth Similarity Index 0.592
  • Travel time at Voyager 1 speed 28,849,336 years

3 siblings around Kepler-324

KOI-1831 d 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
Kepler-324 b Rocky Terrestrial 1.14 2,414.40 4.385 935 2014
Kepler-324 e Sub-Neptune 2.04 235.01 13.979 635 2021
KOI-1831 d this Rocky Terrestrial 1.13 2.23 34.169 475 2021
Kepler-324 c Sub-Neptune 3.15 6.20 51.806 410 2014

KOI-1831 d Planet Profile

Physical Specs

Radius
1.13 R⊕
Radius (Jupiter)
0.101 R♃
Mass
2.23 M⊕
Mass (Jupiter)
0.007 M♃
Density
9.95 g/cm³
Surface Gravity
1.75 g (Earth)

Classification

Planet Type

Rocky Terrestrial

ESI Score 0.592
HZ Position Inner
Controversial No

Discovery

Year 2021
Method Transit
Facility Kepler
Telescope 0.95 m Kepler Telescope

Size rank in cohort

Rank by radius

#180of 570

top 31.4%

This planet

1.13R⊕

Rocky Terrestrial median

1.01R⊕

Nearest-size peers

Metric Earth KOI-1831 d Jupiter
Radius (R⊕)1.001.1311.21
Mass (M⊕)1.002.23317.83
Density (g/cm³)5.519.951.33
Surface Gravity (g)1.001.752.53
Insolation (S⊕)1.0011.800.037

Alternative Mass Estimates

Method Value Interpretation
Best measured mass 2.230 M⊕ Direct mass measurement (not derived).

Star Catalogue Identifiers

TIC

TIC 243271716

Gaia DR2

Gaia DR2 2132078120004385152

Gaia DR3

Gaia DR3 2132078120004385152

System

Kepler-324

Percentile among Rocky Terrestrial cohort

Radius 1.130 R⊕ · percentile 66 / cohort 570
Mass 2.230 M⊕ · percentile 92 / cohort 570
Orbital period 34.17 d · percentile 98 / cohort 567
Distance 501.57 pc · percentile 64 / cohort 566
ESI 0.592 · percentile 77 / cohort 570

Orbit & Habitability

Orbital Dynamics

Period
34.169 days
Semi-major axis
0.1992 AU
Eccentricity
0.000
Inclination
89.62 °

Year Length

A year here lasts approximately 34.17 Earth days (9.4% of a terrestrial year) on a nearly circular orbit at a mean orbital distance of 0.1992 AU.

Transit Fingerprint

Depth

0.020 %

Duration

4.487 h

Impact parameter b

0.319

Rp / R★

0.012235

Transit midpoint (BJD)

2,454,981.8051

Photometric dip

Transit produces a flux drop of 204 ppm lasting ≈ 4.49 h.

Extended Orbital Architecture

Planet / star radius ratio

0.012235

Semi-major axis / stellar radius

48.562

Impact parameter (b)

0.319

Transit mid-time (BJD)

2,454,981.8051

Angular separation (arcsec)

0.39700

Eq. Temperature

475K

(202 °C)

Insolation (S⊕)

11.80

Earth = 1.00

Earth Similarity (ESI)

0.592

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

Ofir et al. 2018

Instrument

Kepler CCD Array

Publication

2018-01

Observation locale

Space

Host System: Kepler-324

Spectral Class

G-type yellow (Sun-like)

Effective Temperature

5,233 K — cooler than the Sun (5,778 K)

Estimated Age

3.39 Gyr — younger than the Sun (4.6 Gyr)

Stellar Radius

0.835 R☉

Stellar Mass

0.901 M☉

Metallicity [Fe/H]

0.18

Extended Stellar Properties

Surface gravity (log g)

4.540 dex

Stellar density

1.852 g/cm³

Metallicity ratio

[Fe/H]

Distance
501.57 parsec
Light-years 1,635.91 ly
V-band magnitude
14.22 mag
Voyager-speed travel 28,849,336 yr

Multi-band Host Photometry — 16 bands

9.515.815.76B14.22V14.09Gaia14.12Kepler13.55TESS14.72Sloan g14.04Sloan r13.87Sloan i13.76Sloan z12.78J12.34H12.29K12.25W112.32W212.62W39.47W4

Astrometric Data

Parallax

1.965 mas

Total Proper Motion

22.463 mas/yr

PM Right Ascension

-2.20 mas/yr

PM Declination

22.36 mas/yr

Galactic Cartesian (pc)

x = 0.184 · y = -0.621 · z = 0.762

Equatorial (J2000)

RA 286.47145° · Dec 49.64909°

Galactic ℓ, b

80.093° · 18.132°

Ecliptic λ, β

304.556° · 71.118°

HTM-20 index

349022935

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