This page summarises the information held within TEPCat for the transiting planetary system K2-18b. Please see here for descriptions of the quantities given below.
| Quantity | Value | Unit |
|---|---|---|
| Reference of discovery paper | 2015ApJ...809...25M | |
| Date of discovery paper | 2015 / 3 / 27 | y / m / d |
| Data/telescope used for discovery | K2 | |
| Right ascension | 11 30 14.51 | h m s |
| Declination | +07 35 18.2 | d m s |
| Right ascension (decimal) | 172.56046 | degrees |
| Declination (decimal) | 7.58839 | degrees |
| V-band apparent magnitude | 13.50 | mag |
| K-band apparent magnitude | 8.899 | mag |
| Transit duration | 0.1110 ( 2.664 ) | day hour |
| Transit depth | 0.27 | % |
| Time of mid-transit | 2457527.91121 ± 0.00007 | HJD or BJD |
| Orbital period | 32.940038 ± 0.000009 | days |
| Reference for orbital ephemeris | 2019ApJ...887L..14B |
| Quantity | Value | Unit |
|---|---|---|
| Stellar effective temperature | 3645 ± 52 | K |
| Stellar metal abundance ([Fe/H] or [M/H]) | +0.10 ± 0.12 | dex |
| Stellar mass | 0.495 ± 0.004 | Msun |
| Stellar radius | 0.469 ± 0.010 | Rsun |
| Stellar logarithmic surface gravity | c.g.s. | |
| Stellar mean density | ρsun g cm-3 | |
| Orbital eccentricity | 0.20 ± 0.08 | |
| Orbital semimajor axis | 0.1591 ± 0.0004 | AU |
| Planetary mass | 0.0299 +0.0049 −0.0059 ( 9.5 +1.6 −1.9 ) | Mjup Mearth |
| Planetary radius | 0.242 ± 0.006 ( 2.713 ± 0.067 ) | Rjup Rearth |
| Planetary surface gravity | 11.5 ± 1.9 3.06 ± 0.07 | m/s2 log(cgs) |
| Planetary mean density | 1.8 ± 0.3 ( 2.39 ± 0.40 ) | ρjup g cm-3 |
| Planetary equilibrium temperature | 265 ± 5 | K |
| Reference of detailed study | arXiv:2503.19908 |
K2-18b does not have an entry in the catalogue of orbital obliquity measurements.
Page generated on 2026/01/29 John Southworth (Keele University, UK)