Key parameters at a glance
- A radius of 5.04 Earth radii
- A mass of 1,175.97 Earth masses
- Surface gravity around 46.30 g
- An orbital period of 5.425 days
- Semi-major axis 0.0409 AU
- Equilibrium temperature 850 K (577 °C)
- Distance from Earth 454.23 light-years
- Earth Similarity Index 0.140
- Travel time at Voyager 1 speed 8,010,362 years
- Almost certainly tidally locked to its host star given the close orbit
K2-33 b Planet Profile
Physical Specs
Classification
Planet Type
Neptune-like
Discovery
Size rank in cohort
Rank by radius
#378of 574
top 65.7%
This planet
5.04R⊕
Neptune-like median
6.39R⊕
Nearest-size peers
| Metric | Earth | K2-33 b | Jupiter |
|---|---|---|---|
| Radius (R⊕) | 1.00 | 5.04 | 11.21 |
| Mass (M⊕) | 1.00 | 1,175.97 | 317.83 |
| Density (g/cm³) | 5.51 | — | 1.33 |
| Surface Gravity (g) | 1.00 | 46.30 | 2.53 |
| Insolation (S⊕) | 1.00 | — | 0.037 |
Alternative Mass Estimates
| Method | Value | Interpretation |
|---|---|---|
| Best measured mass | 1,175.971 M⊕ | Direct mass measurement (not derived). |
Star Catalogue Identifiers
TIC
TIC 49040478
Gaia DR2
Gaia DR2 6245758900889486720
Gaia DR3
Gaia DR3 6245758900889486720
System
K2-33
Percentile among Neptune-like cohort
Orbit & Habitability
Orbital Dynamics
Year Length
A year here lasts approximately 5.42 Earth days (1.5% of a terrestrial year) on a nearly circular orbit at a mean orbital distance of 0.0409 AU.
Transit Fingerprint
Depth
0.302 %
Duration
4.080 h
Impact parameter b
0.160
Rp / R★
0.043200
Transit midpoint (BJD)
2,456,898.6929
Photometric dip
Transit produces a flux drop of 3,018 ppm lasting ≈ 4.08 h.
Extended Orbital Architecture
Planet / star radius ratio
0.043200
Semi-major axis / stellar radius
10.400
Impact parameter (b)
0.160
Transit mid-time (BJD)
2,456,898.6929
Long. of periastron (ω)
0.00°
Angular separation (arcsec)
0.29400
Eq. Temperature
850K
(577 °C)
Insolation (S⊕)
—
Earth = 1.00
Earth Similarity (ESI)
0.140
0 = alien, 1 = Earth-identical
Insufficient insolation data — the surface is too hot to retain surface water. Close-orbiting tidally-locked around a cool host.
Discovery Paper
Primary reference
David et al. 2016Instrument
Kepler CCD Array
Publication
2016-06
Observation locale
Space
Discovery cohort
Planets confirmed in 2016 at K2 (12 shown).
Host System: K2-33
Spectral Class
M-type red dwarf
Effective Temperature
3,540 K — cooler than the Sun (5,778 K)
Estimated Age
0.01 Gyr — younger than the Sun (4.6 Gyr)
Stellar Radius
1.050 R☉
Stellar Mass
0.560 M☉
Metallicity [Fe/H]
—
Extended Stellar Properties
Surface gravity (log g)
4.063 dex
Stellar density
0.720 g/cm³
Systemic radial velocity
-6.70 km/s
Rotational v·sin i
8.20 km/s
Rotation period
6.29 days
Multi-band Host Photometry — 17 bands
Astrometric Data
Parallax
7.153 mas
Total Proper Motion
25.877 mas/yr
PM Right Ascension
-9.71 mas/yr
PM Declination
-23.99 mas/yr
Galactic Cartesian (pc)
x = -0.435 · y = -0.838 · z = -0.331
Equatorial (J2000)
RA 242.56136° · Dec -19.31938°
Galactic ℓ, b
354.420° · 23.100°
Ecliptic λ, β
244.208° · 1.697°
HTM-20 index
1420897720
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