Key parameters at a glance
- A radius of 1.90 Earth radii
- A mass of 4.27 Earth masses
- Surface gravity around 1.18 g
- An orbital period of 40.718 days
- Semi-major axis 0.1937 AU
- Equilibrium temperature 381 K (108 °C)
- Distance from Earth 237.44 light-years
- Earth Similarity Index 0.689
- Travel time at Voyager 1 speed 4,187,270 years
- Almost certainly tidally locked to its host star given the close orbit
Context from the literature
K2-155d is a potentially habitable Super-Earth exoplanet in the K2-155 system. It is the outermost of three known planets orbiting around the K-type star K2-155 in the constellation Taurus, approximately 290 light years from Earth. It is one of 15 new exoplanets around red dwarf stars discovered by Japanese astronomer Teruyuki Hirano of the Tokyo Institute of Technology and his team. The team used data from NASA's Kepler Space Telescope during its extended K2 "Second Light" mission. K2-155d orbits near the so-called habitable zone of its system, and has the potential to host liquid water.
Excerpted from Wikipedia · full article
2 siblings around K2-155
K2-155 d shares its host star with 2 other confirmed planets. Side-by-side measurements below.
K2-155 d Planet Profile
Physical Specs
Classification
Planet Type
Super-Earth
Discovery
Size rank in cohort
Rank by radius
#125of 1176
top 10.5%
This planet
1.90R⊕
Super-Earth median
1.60R⊕
Nearest-size peers
| Metric | Earth | K2-155 d | Jupiter |
|---|---|---|---|
| Radius (R⊕) | 1.00 | 1.90 | 11.21 |
| Mass (M⊕) | 1.00 | 4.27 | 317.83 |
| Density (g/cm³) | 5.51 | 3.42 | 1.33 |
| Surface Gravity (g) | 1.00 | 1.18 | 2.53 |
| Insolation (S⊕) | 1.00 | 1.67 | 0.037 |
Star Catalogue Identifiers
TIC
TIC 17307715
Gaia DR2
Gaia DR2 145333927996558976
Gaia DR3
Gaia DR3 145333927996558976
System
K2-155
Percentile among Super-Earth cohort
Orbit & Habitability
Orbital Dynamics
Year Length
A year here lasts approximately 40.72 Earth days (11.1% of a terrestrial year) at a mean orbital distance of 0.1937 AU.
Transit Fingerprint
Depth
0.074 %
Duration
4.464 h
Impact parameter b
0.440
Rp / R★
0.027300
Transit midpoint (BJD)
2,457,782.8324
Photometric dip
Transit produces a flux drop of 740 ppm lasting ≈ 4.46 h.
Extended Orbital Architecture
Planet / star radius ratio
0.027300
Semi-major axis / stellar radius
63.300
Impact parameter (b)
0.440
Transit mid-time (BJD)
2,457,782.8324
Angular separation (arcsec)
2.66000
Eq. Temperature
381K
(108 °C)
Insolation (S⊕)
1.67
Earth = 1.00
Earth Similarity (ESI)
0.689
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-158 c
Super-Earth · K-type orange
Radius 1.90 R⊕ · 1,028.0 ly
Kepler-601 b
Super-Earth · K-type orange
Radius 1.90 R⊕ · 1,353.0 ly
Kepler-196 b
Super-Earth · K-type orange
Radius 1.90 R⊕ · 1,472.0 ly
Kepler-1669 c
Super-Earth · K-type orange
Radius 1.90 R⊕ · 1,772.5 ly
K2-47 b
Super-Earth · K-type orange
Radius 1.89 R⊕ · 1,141.2 ly
TOI-5789 d
Super-Earth · K-type orange
Radius 1.91 R⊕ · 66.7 ly