Key parameters at a glance
- A radius of 2.19 Earth radii
- A mass of 7.49 Earth masses
- Surface gravity around 1.56 g
- An orbital period of 4.005 days
- Semi-major axis 0.0327 AU
- Distance from Earth 258.64 light-years
- Earth Similarity Index 0.789
- Travel time at Voyager 1 speed 4,561,158 years
- Almost certainly tidally locked to its host star given the close orbit
1 sibling around K2-146
K2-146 c shares its host star with 1 other confirmed planet. Side-by-side measurements below.
| Planet | Type | Radius (R⊕) | Mass (M⊕) | Period (d) | Eq. T (K) | Year |
|---|---|---|---|---|---|---|
| K2-146 b | Sub-Neptune | 2.05 | 5.77 | 2.645 | 534 | 2018 |
| K2-146 c this | Sub-Neptune | 2.19 | 7.49 | 4.005 | — | 2019 |
K2-146 c Planet Profile
Physical Specs
Classification
Planet Type
Sub-Neptune
Discovery
Size rank in cohort
Rank by radius
#1691of 1978
top 85.4%
This planet
2.19R⊕
Sub-Neptune median
2.71R⊕
Nearest-size peers
| Metric | Earth | K2-146 c | Jupiter |
|---|---|---|---|
| Radius (R⊕) | 1.00 | 2.19 | 11.21 |
| Mass (M⊕) | 1.00 | 7.49 | 317.83 |
| Density (g/cm³) | 5.51 | 3.92 | 1.33 |
| Surface Gravity (g) | 1.00 | 1.56 | 2.53 |
| Insolation (S⊕) | 1.00 | — | 0.037 |
Alternative Mass Estimates
| Method | Value | Interpretation |
|---|---|---|
| Best measured mass | 7.490 M⊕ | Direct mass measurement (not derived). |
Star Catalogue Identifiers
TIC
TIC 175261852
Gaia DR2
Gaia DR2 661192902209491456
Gaia DR3
Gaia DR3 661192902209491456
System
K2-146
Percentile among Sub-Neptune cohort
Orbit & Habitability
Orbital Dynamics
Year Length
A year here lasts approximately 4.00 Earth days (1.1% of a terrestrial year) on a nearly circular orbit at a mean orbital distance of 0.0327 AU.
Transit Fingerprint
Impact parameter b
0.930
Rp / R★
0.061200
Transit midpoint (BJD)
2,458,204.1316
Extended Orbital Architecture
Planet / star radius ratio
0.061200
Semi-major axis / stellar radius
20.064
Impact parameter (b)
0.930
Transit mid-time (BJD)
2,458,204.1316
Long. of periastron (ω)
130.00°
Angular separation (arcsec)
0.41200
Eq. Temperature
—
Insolation (S⊕)
—
Earth = 1.00
Earth Similarity (ESI)
0.789
0 = alien, 1 = Earth-identical
Insufficient insolation data. Close-orbiting tidally-locked around a cool host.
Detection Signatures
Transit photometry
A transit dip has been observed from at least one telescope.
Transit timing variations
Gravitational interactions from neighbours have been detected.
Discovery Paper
Primary reference
Hamann et al. 2019Instrument
Kepler CCD Array
Publication
2019-09
Observation locale
Space
Discovery cohort
Planets confirmed in 2019 at K2 (12 shown).
Host System: K2-146
Spectral Class
M-type red dwarf
Effective Temperature
3,385 K — cooler than the Sun (5,778 K)
Estimated Age
5.00 Gyr — older than the Sun (4.6 Gyr)
Stellar Radius
0.330 R☉
Stellar Mass
0.331 M☉
Metallicity [Fe/H]
-0.02
Extended Stellar Properties
Surface gravity (log g)
4.898 dex
Stellar density
13.100 g/cm³
Systemic radial velocity
40.60 km/s
Rotational v·sin i
2.00 km/s
Metallicity ratio
[Fe/H]
Multi-band Host Photometry — 12 bands
Astrometric Data
Parallax
12.582 mas
Total Proper Motion
129.998 mas/yr
PM Right Ascension
-15.92 mas/yr
PM Declination
-129.02 mas/yr
Galactic Cartesian (pc)
x = -0.608 · y = 0.724 · z = 0.327
Equatorial (J2000)
RA 130.02670° · Dec 19.09234°
Galactic ℓ, b
206.528° · 32.219°
Ecliptic λ, β
127.428° · 0.702°
HTM-20 index
62696340
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