YY Geminorum

data from Smithsonian Astrophysical Observatory Star Catalog (SAO Staff 1966; USNO, ADC 1990)

position and proper motion:

position (B1950)	RA: 7h 31min 26.284sec	DEC: +31° 58' 50.39''	ą0.037 arcsec
position (2000.72)	RA: 7h 34min 41sec	DEC: +31° 52' 8''	JD: 2451809.27
position (J2000)	RA: 7h 34min 37.494sec	DEC: +31° 52' 9.46''
proper motion B1950 (FK4)	RA: -0.0154 arcsec/a	DEC: -0.108 arcsec/a	ą0.006 arcsec/a in RA ą0.008 arcsec/a in DEC
proper motion J2000 (FK5)	RA: -0.0155 arcsec/a	DEC: -0.104 arcsec/a
source of proper motion data	Determined by source catalog

magnitude:

visual	9.1 (accuracy: 1 decimal)
source of visual magnitude data	Based on Durchmusterung magnitudes and visual estimates

spectral information:

spectral class	M1e
source of spectral data	Taken from the Henry Draper Catalogue or no spectrum in source catalog.

remarks for duplicity and variability

Double star in Aitken's Double Star Catalogue (Aitken 1932)

catalogues

source catalogue	GC, catalogue number: 10121
Durchmusterung	BD+32 1582
Boss General Catalogue	10121

data from Combined General Catalogue of Variable Stars (Vol. I-III) (Kholopov+ 1998)

position:

position (equinox 1950.0)

RA: 7h 31min 26.3sec

DEC: +31° 58' 50''

variability informations:

variability type	EA/DM+UV	close binary eclipsing system eruptive variable star
magnitute at max. brightness	8.91
magnitute at min. brightness	9.6
photometric system	visual, photovisual or Johnson's V
epoch for maximum light [JD]	2424595.8172 21. March 1926, 07:36:46 UT
period [d]	0.81428254
next maximum light [JD]	2451809.95396934 22. September 2000, 10:53:43 UT
duration of the eclipse	07 % of period the duration of the light constancy phase at minimum light is equal to zero

spectral information

spectral class

M1Ve+M1Ve

references

to a study	Vol. I GCVS (see Kholopov et al. 1985-1988)
to a chart/photograph	Vol. I GCVS (see Kholopov et al. 1985-1988)

miscanellous

ID in the GCVS catalogue	38/52
constellation	Gemini
notes on existence	The star is equivalent to '0380053 YZ'.
There are notes in published catalog.

variability type description

variability type	description
EA	Eclipsing binary systems. These are binary systems with orbital planes so close to the observer's line of sight (the inclination i of the orbital plane to the plane orthogonal to the line of sight is close to 90 deg) that the components periodically eclipse each other. Consequently, the observer finds changes of the apparent combined brightness of the system with the period coincident with that of the components' orbital motion. EA Algol (Beta Persei)-type eclipsing systems. Binaries with spherical or slightly ellipsoidal components. It is possible to specify, for their light curves, the moments of the beginning and end of the eclipses. Between eclipses the light remains almost constant or varies insignificantly because of reflection effects, slight ellipsoidality of components, or physical variations. Secondary minima may be absent. An extremely wide range of periods is observed, from 0.2 to >= 10000 days. Light amplitudes are also quite different and may reach several magnitudes. EB Beta Lyrae-type eclipsing systems. These are eclipsing systems having ellipsoidal components and light curves for which it is impossible to specify the exact times of onset and end of eclipses because of a continuous change of a system's apparent combined brightness between eclipses; secondary minimum is observed in all cases, its depth usually being considerably smaller than that of the primary minimum; periods are mainly longer than 1 day. The components generally belong to early spectral types (B-A). Light amplitudes are usually <2 mag in V. EW W Ursae Majoris-type eclipsing variables. These are eclipsers with periods shorter than 1 days, consisting of ellipsoidal components almost in contact and having light curves for which it is impossible to specify the exact times of onset and end of eclipses. The depths of the primary and secondary minima are almost equal or differ insignificantly. Light amplitudes are usually <0.8 mag in V. The components generally belong to spectral types F-G and later.
DM	Detached main-sequence systems. Both components are main-sequence stars and do not fill their inner Roche lobes.
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.