Key parameters at a glance
- A radius of 2.15 Earth radii
- A mass of 5.27 Earth masses
- Surface gravity around 1.14 g
- An orbital period of 6.688 days
- Semi-major axis 0.0617 AU
- Distance from Earth 1,294.56 light-years
- Earth Similarity Index 0.759
- Travel time at Voyager 1 speed 22,829,486 years
- Almost certainly tidally locked to its host star given the close orbit
K2-42 b Planet Profile
Physical Specs
Classification
Planet Type
Sub-Neptune
Discovery
Size rank in cohort
Rank by radius
#1741of 1978
top 88.0%
This planet
2.15R⊕
Sub-Neptune median
2.71R⊕
Nearest-size peers
| Metric | Earth | K2-42 b | Jupiter |
|---|---|---|---|
| Radius (R⊕) | 1.00 | 2.15 | 11.21 |
| Mass (M⊕) | 1.00 | 5.27 | 317.83 |
| Density (g/cm³) | 5.51 | 2.91 | 1.33 |
| Surface Gravity (g) | 1.00 | 1.14 | 2.53 |
| Insolation (S⊕) | 1.00 | 44.10 | 0.037 |
Star Catalogue Identifiers
TIC
TIC 82054726
Gaia DR2
Gaia DR2 3599651986730350464
Gaia DR3
Gaia DR3 3599651986730350464
System
K2-42
Percentile among Sub-Neptune cohort
Orbit & Habitability
Orbital Dynamics
Year Length
A year here lasts approximately 6.69 Earth days (1.8% of a terrestrial year) at a mean orbital distance of 0.0617 AU.
Transit Fingerprint
Depth
0.104 %
Duration
3.040 h
Impact parameter b
0.000
Rp / R★
0.030400
Transit midpoint (BJD)
2,456,814.6763
Photometric dip
Transit produces a flux drop of 1,042 ppm lasting ≈ 3.04 h.
Extended Orbital Architecture
Planet / star radius ratio
0.030400
Semi-major axis / stellar radius
14.000
Impact parameter (b)
0.000
Transit mid-time (BJD)
2,456,814.6763
Angular separation (arcsec)
0.15500
Eq. Temperature
—
Insolation (S⊕)
44.10
Earth = 1.00
Earth Similarity (ESI)
0.759
0 = alien, 1 = Earth-identical
Inside the inner HZ boundary (too hot for liquid water). Close-orbiting tidally-locked around a cool host.
Discovery Paper
Primary reference
Crossfield et al. 2016Instrument
Kepler CCD Array
Publication
2016-09
Observation locale
Space
Discovery cohort
Planets confirmed in 2016 at K2 (12 shown).
Host System: K2-42
Spectral Class
K-type orange
Effective Temperature
4,613 K — cooler than the Sun (5,778 K)
Estimated Age
—
Stellar Radius
0.643 R☉
Stellar Mass
0.702 M☉
Metallicity [Fe/H]
—
Multi-band Host Photometry — 12 bands
Astrometric Data
Parallax
2.492 mas
Total Proper Motion
33.627 mas/yr
PM Right Ascension
10.44 mas/yr
PM Declination
-31.97 mas/yr
Galactic Cartesian (pc)
x = -0.994 · y = 0.058 · z = -0.090
Equatorial (J2000)
RA 176.66576° · Dec -5.17205°
Galactic ℓ, b
274.655° · 54.105°
Ecliptic λ, β
179.000° · -6.070°
HTM-20 index
295551435
Similar Worlds
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Sub-Neptune · K-type orange
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Kepler-1013 b
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Kepler-1455 b
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Kepler-437 b
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