EV Lacertae
catalogues and names
catalogues and names | EV Lac |
data from Combined General Catalogue of Variable Stars (Vol. I-III) (Kholopov+ 1998)
position:
position (equinox 1950.0) | RA: 22h 44min 39sec | DEC: +44° 4' 30'' | ± 1 sec / ± 0.1 arcmin |
variability informations:
variability type | UV+BY | eruptive variable star rotating variable star |
magnitute at max. brightness | 8.28 | |
magnitute at min. brightness | 11.83 | |
photometric system |
spectral information
spectral class | M4.5Ve |
references
to a study | Vol. I GCVS (see Kholopov et al. 1985-1988) |
to a chart/photograph | Vol. II GCVS |
miscanellous
ID in the GCVS catalogue | 45/165 |
constellation | Lacerta |
notes on existence | The star is equivalent to '0450166 EW'. |
There are notes in published catalog. |
variability type description
variability type | description |
UV | Eruptive variables of the UV Ceti type, these are K Ve-M Ve stars sometimes displaying flare activity with amplitudes from several tenths of a magnitude up to 6 mag in V. The amplitude is considerably greater in the ultraviolet spectral region. Maximum light is attained in several seconds or dozens of seconds after the beginning of a flare; the star returns to its normal brightness in several minutes or dozens of minutes. |
BY | BY Draconis-type variables, which are emission-line dwarfs of dKe-dMe spectral type showing quasiperiodic light changes with periods from a fraction of a day to 120 days and amplitudes from several hundredths to 0.5 mag in V. The light variability is caused by axial rotation of a star with a variable degree of nonuniformity of the surface brightness (spots) and chromospheric activity. Some of these stars also show flares similar to those of UV Cet stars, and in those cases they also belong to the latter type and are simultaneously considered eruptive variables. |