Key parameters at a glance
- A radius of 2.93 Earth radii
- A mass of 8.92 Earth masses
- Surface gravity around 1.04 g
- An orbital period of 21.761 days
- Semi-major axis 0.1399 AU
- Equilibrium temperature 486 K (213 °C)
- Distance from Earth 554.30 light-years
- Earth Similarity Index 0.478
- Travel time at Voyager 1 speed 9,775,002 years
- Almost certainly tidally locked to its host star given the close orbit
Kepler-1731 b Planet Profile
Physical Specs
Classification
Planet Type
Sub-Neptune
Discovery
Size rank in cohort
Rank by radius
#584of 1978
top 29.5%
This planet
2.93R⊕
Sub-Neptune median
2.71R⊕
Nearest-size peers
| Metric | Earth | Kepler-1731 b | Jupiter |
|---|---|---|---|
| Radius (R⊕) | 1.00 | 2.93 | 11.21 |
| Mass (M⊕) | 1.00 | 8.92 | 317.83 |
| Density (g/cm³) | 5.51 | 1.94 | 1.33 |
| Surface Gravity (g) | 1.00 | 1.04 | 2.53 |
| Insolation (S⊕) | 1.00 | 13.30 | 0.037 |
Star Catalogue Identifiers
TIC
TIC 137099260
Gaia DR2
Gaia DR2 2050239300586448000
Gaia DR3
Gaia DR3 2050239300586448000
System
Kepler-1731
Percentile among Sub-Neptune cohort
Orbit & Habitability
Orbital Dynamics
Year Length
A year here lasts approximately 21.76 Earth days (6.0% of a terrestrial year) on a nearly circular orbit at a mean orbital distance of 0.1399 AU.
Transit Fingerprint
Depth
0.124 %
Duration
1.266 h
Impact parameter b
0.916
Rp / R★
0.032165
Transit midpoint (BJD)
2,454,999.5405
Photometric dip
Transit produces a flux drop of 1,236 ppm lasting ≈ 1.27 h.
Extended Orbital Architecture
Planet / star radius ratio
0.032165
Semi-major axis / stellar radius
137.070
Impact parameter (b)
0.916
Transit mid-time (BJD)
2,454,999.5405
Angular separation (arcsec)
0.82300
Eq. Temperature
486K
(213 °C)
Insolation (S⊕)
13.30
Earth = 1.00
Earth Similarity (ESI)
0.478
0 = alien, 1 = Earth-identical
Inside the inner HZ boundary (too hot for liquid water) — the surface is too hot to retain surface water. Close-orbiting tidally-locked around a cool host.
Discovery Paper
Primary reference
Valizadegan et al. 2022Instrument
Kepler CCD Array
Publication
2022-02
Observation locale
Space
Discovery cohort
Planets confirmed in 2021 at Kepler (12 shown).
Host System: Kepler-1731
Spectral Class
K-type orange
Effective Temperature
4,859 K — cooler than the Sun (5,778 K)
Estimated Age
2.14 Gyr — younger than the Sun (4.6 Gyr)
Stellar Radius
0.720 R☉
Stellar Mass
0.781 M☉
Metallicity [Fe/H]
0.00
Extended Stellar Properties
Surface gravity (log g)
4.612 dex
Stellar density
102.865 g/cm³
Metallicity ratio
[Fe/H]
Multi-band Host Photometry — 17 bands
Astrometric Data
Parallax
5.855 mas
Total Proper Motion
35.902 mas/yr
PM Right Ascension
-7.79 mas/yr
PM Declination
-35.05 mas/yr
Galactic Cartesian (pc)
x = 0.290 · y = -0.747 · z = 0.598
Equatorial (J2000)
RA 291.25442° · Dec 36.74343°
Galactic ℓ, b
69.393° · 9.710°
Ecliptic λ, β
303.001° · 57.772°
HTM-20 index
-1679563530
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TOI-125 d
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TOI-178 g
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TOI-824 b
Sub-Neptune · K-type orange
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TOI-815 b
Sub-Neptune · K-type orange
Radius 2.94 R⊕ · 194.8 ly