Key parameters at a glance
- A radius of 4.16 Earth radii
- A mass of 16.10 Earth masses
- Surface gravity around 0.93 g
- An orbital period of 704.198 days
- Semi-major axis 1.2190 AU
- Equilibrium temperature 185 K (-88 °C)
- Distance from Earth 1,136.84 light-years
- Earth Similarity Index 0.442
- Travel time at Voyager 1 speed 20,048,222 years
Context from the literature
Kepler-421b is an exoplanet that, as of July 2014, has the longest known year of any transiting planet, although not as long as the planets that have been directly imaged, or many of the planets found by the radial-velocity method, or as long as some transiting planet candidates which are listed as planets in the Extrasolar Planets Encyclopaedia. It is the first transiting-planet found near the snow-line.
Excerpted from Wikipedia · full article
Kepler-421 b Planet Profile
Physical Specs
Classification
Planet Type
Neptune-like
Discovery
Size rank in cohort
Rank by radius
#529of 574
top 92.0%
This planet
4.16R⊕
Neptune-like median
6.39R⊕
Nearest-size peers
| Metric | Earth | Kepler-421 b | Jupiter |
|---|---|---|---|
| Radius (R⊕) | 1.00 | 4.16 | 11.21 |
| Mass (M⊕) | 1.00 | 16.10 | 317.83 |
| Density (g/cm³) | 5.51 | 1.23 | 1.33 |
| Surface Gravity (g) | 1.00 | 0.93 | 2.53 |
| Insolation (S⊕) | 1.00 | 0.20 | 0.037 |
Star Catalogue Identifiers
TIC
TIC 164522394
Gaia DR2
Gaia DR2 2106891671567353728
Gaia DR3
Gaia DR3 2106891671567353728
System
Kepler-421
Percentile among Neptune-like cohort
Orbit & Habitability
Orbital Dynamics
Year Length
A year here lasts about 1.93 Earth years on a nearly circular orbit at a mean orbital distance of 1.2190 AU.
Transit Fingerprint
Depth
0.232 %
Duration
15.790 h
Impact parameter b
0.210
Rp / R★
0.050080
Transit midpoint (BJD)
2,455,325.7674
Photometric dip
Transit produces a flux drop of 2,319 ppm lasting ≈ 15.79 h.
Extended Orbital Architecture
Planet / star radius ratio
0.050080
Semi-major axis / stellar radius
346.000
Impact parameter (b)
0.210
Transit mid-time (BJD)
2,455,325.7674
Long. of periastron (ω)
160.00°
Angular separation (arcsec)
3.50000
Eq. Temperature
185K
(-88 °C)
Insolation (S⊕)
0.20
Earth = 1.00
Earth Similarity (ESI)
0.442
0 = alien, 1 = Earth-identical
Beyond the outer HZ boundary (too cold) — surface water would be frozen.
Discovery Paper
Primary reference
Kipping et al. 2014Instrument
Kepler CCD Array
Publication
2014-07
Observation locale
Space
Discovery cohort
Planets confirmed in 2014 at Kepler (12 shown).
Host System: Kepler-421
Spectral Class
G-type yellow (Sun-like)
Effective Temperature
5,308 K — cooler than the Sun (5,778 K)
Estimated Age
4.00 Gyr — younger than the Sun (4.6 Gyr)
Stellar Radius
0.757 R☉
Stellar Mass
0.794 M☉
Metallicity [Fe/H]
-0.25
Extended Stellar Properties
Surface gravity (log g)
4.610 dex
Stellar density
1.580 g/cm³
Rotational v·sin i
0.00 km/s
Metallicity ratio
[Fe/H]
Multi-band Host Photometry — 16 bands
Astrometric Data
Parallax
2.840 mas
Total Proper Motion
20.788 mas/yr
PM Right Ascension
-4.01 mas/yr
PM Declination
-20.40 mas/yr
Galactic Cartesian (pc)
x = 0.162 · y = -0.687 · z = 0.708
Equatorial (J2000)
RA 283.25681° · Dec 45.08768°
Galactic ℓ, b
74.789° · 18.576°
Ecliptic λ, β
294.895° · 67.384°
HTM-20 index
384537925
Similar Worlds
HD 164595 b
Neptune-like · G-type yellow (Sun-like)
Radius 4.16 R⊕ · 92.2 ly
K2-79 b
Neptune-like · G-type yellow (Sun-like)
Radius 4.15 R⊕ · 835.0 ly
Kepler-315 c
Neptune-like · G-type yellow (Sun-like)
Radius 4.15 R⊕ · 3,785.5 ly
K2-198 b
Neptune-like · G-type yellow (Sun-like)
Radius 4.19 R⊕ · 360.6 ly
Kepler-610 b
Neptune-like · G-type yellow (Sun-like)
Radius 4.19 R⊕ · 2,758.7 ly
Kepler-11 e
Neptune-like · G-type yellow (Sun-like)
Radius 4.19 R⊕ · 2,108.1 ly