Key parameters at a glance
- A radius of 2.60 Earth radii
- A mass of 7.27 Earth masses
- Surface gravity around 1.08 g
- An orbital period of 13.850 days
- Semi-major axis 0.0946 AU
- Equilibrium temperature 583 K (310 °C)
- Distance from Earth 237.44 light-years
- Earth Similarity Index 0.425
- Travel time at Voyager 1 speed 4,187,270 years
- Almost certainly tidally locked to its host star given the close orbit
2 siblings around K2-155
K2-155 c shares its host star with 2 other confirmed planets. Side-by-side measurements below.
K2-155 c Planet Profile
Physical Specs
Classification
Planet Type
Sub-Neptune
Discovery
Size rank in cohort
Rank by radius
#1017of 1978
top 51.4%
This planet
2.60R⊕
Sub-Neptune median
2.71R⊕
Nearest-size peers
| Metric | Earth | K2-155 c | Jupiter |
|---|---|---|---|
| Radius (R⊕) | 1.00 | 2.60 | 11.21 |
| Mass (M⊕) | 1.00 | 7.27 | 317.83 |
| Density (g/cm³) | 5.51 | 2.27 | 1.33 |
| Surface Gravity (g) | 1.00 | 1.08 | 2.53 |
| Insolation (S⊕) | 1.00 | 7.00 | 0.037 |
Star Catalogue Identifiers
TIC
TIC 17307715
Gaia DR2
Gaia DR2 145333927996558976
Gaia DR3
Gaia DR3 145333927996558976
System
K2-155
Percentile among Sub-Neptune cohort
Orbit & Habitability
Orbital Dynamics
Year Length
A year here lasts approximately 13.85 Earth days (3.8% of a terrestrial year) at a mean orbital distance of 0.0946 AU.
Transit Fingerprint
Depth
0.103 %
Duration
3.528 h
Impact parameter b
0.450
Rp / R★
0.032100
Transit midpoint (BJD)
2,457,994.6647
Photometric dip
Transit produces a flux drop of 1,030 ppm lasting ≈ 3.53 h.
Extended Orbital Architecture
Planet / star radius ratio
0.032100
Semi-major axis / stellar radius
27.000
Impact parameter (b)
0.450
Transit mid-time (BJD)
2,457,994.6647
Angular separation (arcsec)
1.30000
Eq. Temperature
583K
(310 °C)
Insolation (S⊕)
7.00
Earth = 1.00
Earth Similarity (ESI)
0.425
0 = alien, 1 = Earth-identical
Inside the inner HZ boundary (too hot for liquid water) — the surface is too hot to retain surface water. Close-orbiting tidally-locked around a cool host.
Discovery Paper
Primary reference
Hirano et al. 2018Instrument
Kepler CCD Array
Publication
2018-03
Observation locale
Space
Discovery cohort
Planets confirmed in 2018 at K2 (12 shown).
Host System: K2-155
Spectral Class
K-type orange
Effective Temperature
4,258 K — cooler than the Sun (5,778 K)
Estimated Age
—
Stellar Radius
0.580 R☉
Stellar Mass
0.650 M☉
Metallicity [Fe/H]
-0.30
Extended Stellar Properties
Surface gravity (log g)
4.600 dex
Stellar density
5.410 g/cm³
Systemic radial velocity
19.10 km/s
Rotation period
34.80 days
Metallicity ratio
[Fe/H]
Multi-band Host Photometry — 18 bands
Astrometric Data
Parallax
13.708 mas
Total Proper Motion
214.791 mas/yr
PM Right Ascension
200.61 mas/yr
PM Declination
-76.76 mas/yr
Galactic Cartesian (pc)
x = 0.387 · y = 0.847 · z = 0.364
Equatorial (J2000)
RA 65.46961° · Dec 21.35326°
Galactic ℓ, b
174.749° · -19.713°
Ecliptic λ, β
67.248° · -0.170°
HTM-20 index
-463828751
Similar Worlds
Kepler-505 b
Sub-Neptune · K-type orange
Radius 2.60 R⊕ · 924.4 ly
K2-90 b
Sub-Neptune · K-type orange
Radius 2.60 R⊕ · 437.7 ly
HD 48948 c
Sub-Neptune · K-type orange
Radius 2.60 R⊕ · 55.1 ly
Kepler-1362 b
Sub-Neptune · K-type orange
Radius 2.60 R⊕ · 2,385.2 ly
Kepler-665 b
Sub-Neptune · K-type orange
Radius 2.60 R⊕ · 1,998.8 ly
HD 18599 b
Sub-Neptune · K-type orange
Radius 2.60 R⊕ · 125.8 ly