This page summarises the information held within TEPCat for the transiting planetary system HAT-P-21. Please see here for descriptions of the quantities given below.
| Quantity | Value | Unit |
|---|---|---|
| Reference of discovery paper | 2011ApJ...742..116B | |
| Date of discovery paper | 2010 / 8 / 23 | y / m / d |
| Data/telescope used for discovery | HAT | |
| Right ascension | 11 25 05.88 | h m s |
| Declination | +41 01 40.6 | d m s |
| Right ascension (decimal) | 171.27450 | degrees |
| Declination (decimal) | 41.02794 | degrees |
| V-band apparent magnitude | 11.69 | mag |
| K-band apparent magnitude | 10.11 | mag |
| Transit duration | 0.1530 ( 3.672 ) | day hour |
| Transit depth | 1.1 | % |
| Time of mid-transit | 2454996.41243 ± 0.00060 | HJD or BJD |
| Orbital period | 4.12449009 ± 0.00000090 | days |
| Reference for orbital ephemeris | 2022A+A...664A.162M |
| Quantity | Value | Unit |
|---|---|---|
| Stellar effective temperature | 5695 ± 45 | K |
| Stellar metal abundance ([Fe/H] or [M/H]) | +0.04 ± 0.09 | dex |
| Stellar mass | 0.998 ± 0.040 | Msun |
| Stellar radius | 1.248 ± 0.050 | Rsun |
| Stellar logarithmic surface gravity | 4.245 ± 0.033 | c.g.s. |
| Stellar mean density | 0.513 ± 0.058 ( 0.724 ± 0.082 ) | ρsun g cm-3 |
| Orbital eccentricity | 0.217 ± 0.010 | |
| Orbital semimajor axis | 0.05037 ± 0.00067 | AU |
| Planetary mass | 4.23 ± 0.16 ( 1344 ± 50 ) | Mjup Mearth |
| Planetary radius | 1.130 ± 0.057 ( 12.67 ± 0.64 ) | Rjup Rearth |
| Planetary surface gravity | 82.1 ± 8.1 3.91 ± 0.04 | m/s2 log(cgs) |
| Planetary mean density | 2.74 ± 0.40 ( 3.63 ± 0.53 ) | ρjup g cm-3 |
| Planetary equilibrium temperature | 1367 ± 27 | K |
| Reference of detailed study | 2022A+A...664A.162M |
| Reference | λ (degrees) |
|---|---|
| Mancini et al. (2022) | −0.7 ± 12.5 |
Page generated on 2025/11/11 John Southworth (Keele University, UK)