Key parameters at a glance
- A radius of 2.87 Earth radii
- A mass of 8.60 Earth masses
- Surface gravity around 1.04 g
- An orbital period of 47.706 days
- Semi-major axis 0.2253 AU
- Equilibrium temperature 347 K (74 °C)
- Distance from Earth 2,028.68 light-years
- Earth Similarity Index 0.636
- Travel time at Voyager 1 speed 35,775,722 years
- Almost certainly tidally locked to its host star given the close orbit
Kepler-1684 b Planet Profile
Physical Specs
Classification
Planet Type
Sub-Neptune
Discovery
Size rank in cohort
Rank by radius
#658of 1978
top 33.2%
This planet
2.87R⊕
Sub-Neptune median
2.71R⊕
Nearest-size peers
| Metric | Earth | Kepler-1684 b | Jupiter |
|---|---|---|---|
| Radius (R⊕) | 1.00 | 2.87 | 11.21 |
| Mass (M⊕) | 1.00 | 8.60 | 317.83 |
| Density (g/cm³) | 5.51 | 2.00 | 1.33 |
| Surface Gravity (g) | 1.00 | 1.04 | 2.53 |
| Insolation (S⊕) | 1.00 | 3.42 | 0.037 |
Star Catalogue Identifiers
TIC
TIC 270789362
Gaia DR2
Gaia DR2 2128117541685424128
Gaia DR3
Gaia DR3 2128117541685424128
System
Kepler-1684
Percentile among Sub-Neptune cohort
Orbit & Habitability
Orbital Dynamics
Year Length
A year here lasts approximately 47.71 Earth days (13.1% of a terrestrial year) on a nearly circular orbit at a mean orbital distance of 0.2253 AU.
Transit Fingerprint
Depth
0.116 %
Duration
5.959 h
Impact parameter b
0.880
Rp / R★
0.038300
Transit midpoint (BJD)
2,454,979.3112
Photometric dip
Transit produces a flux drop of 1,162 ppm lasting ≈ 5.96 h.
Extended Orbital Architecture
Planet / star radius ratio
0.038300
Semi-major axis / stellar radius
24.200
Impact parameter (b)
0.880
Transit mid-time (BJD)
2,454,979.3112
Angular separation (arcsec)
0.36200
Eq. Temperature
347K
(74 °C)
Insolation (S⊕)
3.42
Earth = 1.00
Earth Similarity (ESI)
0.636
0 = alien, 1 = Earth-identical
Inside the inner HZ boundary (too hot for liquid water) — liquid water is physically possible with adequate atmospheric pressure. Close-orbiting tidally-locked around a cool host.
Discovery Paper
Primary reference
Armstrong et al. 2021Instrument
Kepler CCD Array
Publication
2021-07
Observation locale
Space
Discovery cohort
Planets confirmed in 2020 at Kepler (12 shown).
Host System: Kepler-1684
Spectral Class
K-type orange
Effective Temperature
4,707 K — cooler than the Sun (5,778 K)
Estimated Age
—
Stellar Radius
0.667 R☉
Stellar Mass
0.750 M☉
Metallicity [Fe/H]
0.13
Extended Stellar Properties
Surface gravity (log g)
4.665 dex
Stellar density
3.567 g/cm³
Metallicity ratio
[M/H]
Multi-band Host Photometry — 15 bands
Astrometric Data
Parallax
1.580 mas
Total Proper Motion
3.905 mas/yr
PM Right Ascension
3.61 mas/yr
PM Declination
-1.48 mas/yr
Galactic Cartesian (pc)
x = 0.281 · y = -0.631 · z = 0.723
Equatorial (J2000)
RA 294.00542° · Dec 46.31066°
Galactic ℓ, b
79.039° · 12.174°
Ecliptic λ, β
313.966° · 66.124°
HTM-20 index
-1408312397
Similar Worlds
HIP 54373 b
Sub-Neptune · K-type orange
Radius 2.87 R⊕ · 61.0 ly
Kepler-391 c
Sub-Neptune · K-type orange
Radius 2.88 R⊕ · 2,835.1 ly
K2-378 b
Sub-Neptune · K-type orange
Radius 2.88 R⊕ · 2,243.9 ly
Kepler-1388 d
Sub-Neptune · K-type orange
Radius 2.86 R⊕ · 1,480.1 ly
Kepler-304 b
Sub-Neptune · K-type orange
Radius 2.86 R⊕ · 1,417.7 ly
TOI-5789 c
Sub-Neptune · K-type orange
Radius 2.86 R⊕ · 66.7 ly