Key parameters at a glance
- A radius of 2.51 Earth radii
- A mass of 15.40 Earth masses
- Surface gravity around 2.44 g
- An orbital period of 50.819 days
- Semi-major axis 0.2573 AU
- Equilibrium temperature 482 K (209 °C)
- Distance from Earth 529.94 light-years
- Earth Similarity Index 0.557
- Travel time at Voyager 1 speed 9,345,518 years
K2-263 b Planet Profile
Physical Specs
Classification
Planet Type
Sub-Neptune
Discovery
Size rank in cohort
Rank by radius
#1157of 1978
top 58.4%
This planet
2.51R⊕
Sub-Neptune median
2.71R⊕
Nearest-size peers
| Metric | Earth | K2-263 b | Jupiter |
|---|---|---|---|
| Radius (R⊕) | 1.00 | 2.51 | 11.21 |
| Mass (M⊕) | 1.00 | 15.40 | 317.83 |
| Density (g/cm³) | 5.51 | 5.65 | 1.33 |
| Surface Gravity (g) | 1.00 | 2.44 | 2.53 |
| Insolation (S⊕) | 1.00 | 8.17 | 0.037 |
Alternative Mass Estimates
| Method | Value | Interpretation |
|---|---|---|
| Best measured mass | 15.400 M⊕ | Direct mass measurement (not derived). |
Star Catalogue Identifiers
TIC
TIC 21276520
Gaia DR2
Gaia DR2 657756997089784960
Gaia DR3
Gaia DR3 657756997089784960
System
K2-263
Percentile among Sub-Neptune cohort
Orbit & Habitability
Orbital Dynamics
Year Length
A year here lasts approximately 50.82 Earth days (13.9% of a terrestrial year) on a nearly circular orbit at a mean orbital distance of 0.2573 AU.
Transit Fingerprint
Depth
0.058 %
Duration
3.750 h
Impact parameter b
0.832
Rp / R★
0.027100
Transit midpoint (BJD)
2,459,534.0662
Photometric dip
Transit produces a flux drop of 582 ppm lasting ≈ 3.75 h.
Extended Orbital Architecture
Planet / star radius ratio
0.027100
Semi-major axis / stellar radius
65.060
Impact parameter (b)
0.832
RV semi-amplitude (K)
2.910 m/s
Transit mid-time (BJD)
2,459,534.0662
Angular separation (arcsec)
1.58000
Eq. Temperature
482K
(209 °C)
Insolation (S⊕)
8.17
Earth = 1.00
Earth Similarity (ESI)
0.557
0 = alien, 1 = Earth-identical
Inside the inner HZ boundary (too hot for liquid water) — the surface is too hot to retain surface water.
Detection Signatures
Transit photometry
A transit dip has been observed from at least one telescope.
Radial velocity
Stellar wobble has been measured spectroscopically.
Discovery Paper
Primary reference
Mortier et al. 2018Instrument
Kepler CCD Array
Publication
2018-12
Observation locale
Space
Discovery cohort
Planets confirmed in 2018 at K2 (12 shown).
Host System: K2-263
Spectral Class
G-type yellow (Sun-like)
Effective Temperature
5,368 K — cooler than the Sun (5,778 K)
Estimated Age
7.00 Gyr — older than the Sun (4.6 Gyr)
Stellar Radius
0.850 R☉
Stellar Mass
0.880 M☉
Metallicity [Fe/H]
-0.08
Extended Stellar Properties
Surface gravity (log g)
4.510 dex
Stellar density
2.020 g/cm³
Systemic radial velocity
30.00 km/s
Rotational v·sin i
2.00 km/s
Metallicity ratio
[M/H]
Multi-band Host Photometry — 17 bands
Astrometric Data
Parallax
6.126 mas
Total Proper Motion
55.600 mas/yr
PM Right Ascension
-55.39 mas/yr
PM Declination
-4.85 mas/yr
Galactic Cartesian (pc)
x = -0.615 · y = 0.741 · z = 0.270
Equatorial (J2000)
RA 129.68213° · Dec 15.68060°
Galactic ℓ, b
210.104° · 30.656°
Ecliptic λ, β
127.980° · -2.680°
HTM-20 index
-1761966326
Similar Worlds
K2-214 b
Sub-Neptune · G-type yellow (Sun-like)
Radius 2.51 R⊕ · 980.6 ly
Kepler-176 d
Sub-Neptune · G-type yellow (Sun-like)
Radius 2.51 R⊕ · 1,719.9 ly
Kepler-1033 b
Sub-Neptune · G-type yellow (Sun-like)
Radius 2.51 R⊕ · 4,747.2 ly
Kepler-1726 b
Sub-Neptune · G-type yellow (Sun-like)
Radius 2.51 R⊕ · 1,273.8 ly
Kepler-1792 b
Sub-Neptune · G-type yellow (Sun-like)
Radius 2.52 R⊕ · 1,960.3 ly
Kepler-129 c
Sub-Neptune · G-type yellow (Sun-like)
Radius 2.52 R⊕ · 1,333.5 ly