XO-4
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Lynx |
| Right ascension | 07h 21m 33.1602s |
| Declination | +58° 16′ 05.110″ |
| Apparent magnitude (V) | 10.674 ± 0.019 |
| Characteristics | |
| Spectral type | F5V |
| Apparent magnitude (B) | 11.240 ± 0.029 |
| Apparent magnitude (V) | 10.674 ± 0.019 |
| Apparent magnitude (J) | 9.667 ± 0.021 |
| Apparent magnitude (H) | 9.476 ± 0.022 |
| Apparent magnitude (K) | 9.406 ± 0.023 |
| Astrometry | |
| Radial velocity (Rv) | 1.74±0.33 km/s |
| Proper motion (μ) | RA: −17.008(12) mas/yr Dec.: 5.463(12) mas/yr |
| Parallax (π) | 3.7812±0.0156 mas |
| Distance | 863 ± 4 ly (264 ± 1 pc) |
| Details | |
| Mass | 1.32±0.02 M☉ |
| Radius | 1.56±0.05 R☉ |
| Surface gravity (log g) | 4.18±0.07 cgs |
| Temperature | 6397±70 K |
| Metallicity [Fe/H] | −0.04±0.03 dex |
| Rotational velocity (v sin i) | 8.8±0.5 km/s |
| Age | 2.1±0.6 Gyr |
| Other designations | |
| Koit, TOI-1721, TIC 51234631, TYC 3793-1994-1, GSC 03793-01994, 2MASS J07213317+5816051 | |
| Database references | |
| SIMBAD | data |
| Exoplanet Archive | data |
XO-4 is a star located approximately 863 light-years away from Earth in the Lynx constellation. It has a magnitude of about 11 and cannot be seen with the naked eye but is visible through a small telescope. A search for a binary companion star using adaptive optics at MMT Observatory was negative.
The star XO-4 is named Koit. The name was selected in the NameExoWorlds campaign by Estonia, during the 100th anniversary of the IAU. Koit is Estonian for dawn, and was named for a character in a folk tale written by Friedrich Robert Faehlmann.