This page summarises the information held within TEPCat for the transiting planetary system K2-138d. Please see here for descriptions of the quantities given below.
| Quantity | Value | Unit |
|---|---|---|
| Reference of discovery paper | 2018AJ....155...57C | |
| Date of discovery paper | 2018 / 1 / 12 | y / m / d |
| Data/telescope used for discovery | K2 | |
| Right ascension | 23 15 47.77 | h m s |
| Declination | −10 50 58.9 | d m s |
| Right ascension (decimal) | 348.94904 | degrees |
| Declination (decimal) | -10.84969 | degrees |
| V-band apparent magnitude | 12.21 | mag |
| K-band apparent magnitude | 10.31 | mag |
| Transit duration | 0.124 ( 2.98 ) | day hour |
| Transit depth | 0.08 | % |
| Time of mid-transit | 2458791.7962 ± 0.0054 | HJD or BJD |
| Orbital period | 5.405362 ± 0.000038 | days |
| Reference for orbital ephemeris | 2024A+A...688A.192V |
| Quantity | Value | Unit |
|---|---|---|
| Stellar effective temperature | 5275 ± 67 | K |
| Stellar metal abundance ([Fe/H] or [M/H]) | +0.06 ± 0.05 | dex |
| Stellar mass | 0.862 ± 0.034 | Msun |
| Stellar radius | 0.845 ± 0.006 | Rsun |
| Stellar logarithmic surface gravity | 4.51 ± 0.03 | c.g.s. |
| Stellar mean density | 1.429 ± 0.064 ( 2.016 ± 0.090 ) | ρsun g cm-3 |
| Orbital eccentricity | 0.0007 +0.0009 −0.0004 | |
| Orbital semimajor axis | 0.05893 +0.00040 −0.00050 | AU |
| Planetary mass | 0.0238 +0.0013 −0.0014 ( 7.57 +0.41 −0.45 ) | Mjup Mearth |
| Planetary radius | 0.2254 ± 0.0048 ( 2.527 ± 0.054 ) | Rjup Rearth |
| Planetary surface gravity | m/s2 | |
| Planetary mean density | 1.93 +0.17 −0.16 ( 2.56 +0.23 −0.21 ) | ρjup g cm-3 |
| Planetary equilibrium temperature | 992 +18 −15 | K |
| Reference of detailed study | 2026A+A...711A.221L |
K2-138d does not have an entry in the catalogue of orbital obliquity measurements.
Page generated on 2026/10/04 John Southworth (Keele University, UK)