CDROM/AJ/V110/P1350 Light Curve Changes (Van Hamme+ 1995) ================================================================================ Periodic Light Curve Changes for Beta Lyrae W. Van Hamme, R. E. Wilson, & E. F. Guinan <1995, AJ, 110, 1350> =1995AJ....110.1350V ================================================================================ Abstract: We apply a variety of classical and recently developed periodicity analyses to light curves of Beta Lyrae in 9 eras that extend over a range of about 150 years. Some new data are tabulated. Most periodic variations that have been reported in the literature do not pass standard significance tests, according to our adopted criteria. Certain other periods do pass the tests, although most do so only for one, or at most two, data sets. Our main findings are that a period of about 9 months is present in all data sets and that it connects extremely well in phase from era to era, all the way back to Baxendell's observations of 1840-1877. The semiamplitude is small but reasonably consistent, averaging about 2% of the flux in the light curve maxima. Any substantially larger excursions that occur are nonperiodic. Phase coherence of the 9 month period is fairly good, even with a linear ephemeris, and becomes excellent if one allows for a slow sinusoidal variation of the 9 month periodicity. There is some evidence for a monotonic decrease in the amplitude of the 9 month periodicity with increasing wavelength. Description: Tables 2-5 present the original observations made with the 38 cm reflector at Villanova (VIL) and the 25 cm automated photoelectric telescope (APT), located on Mount Hopkins, Arizona. All differential magnitudes are with respect to the comparison star Gam Lyr. The Halpha and Hbeta filters are broad, with full width at half maximum (FWHM) 29 and 18 nm, respectively. The effective wavelengths are 660 and 487 nm. The Balmer lines presumably have only minor influences on these rather wide bandpasses. File Summary: -------------------------------------------------------------------------------- File Name Lrecl Records Explanations -------------------------------------------------------------------------------- table2.dat 92 312 beta Lyrae Villanova Halpha (wide) observations table3.dat 92 167 beta Lyrae Villanova Hbeta (wide) observations table4.dat 92 136 beta Lyrae Villanova Stromgren y observations table5.dat 54 899 beta Lyrae APT observations -------------------------------------------------------------------------------- Byte-by-byte Description of file: table2.dat table3.dat table4.dat -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 1-11 D11.5 day HJD1 Heliocentric Julian Date 1 12-20 F9.4 mag dm1 Differential magnitude 1 21-24 4X --- --- Blank 25-35 D11.5 day HJD2 Heliocentric Julian Date 2 36-44 F9.4 mag dm2 Differential magnitude 2 45-48 4X --- --- Blank 49-59 D11.5 day HJD3 []? Heliocentric Julian Date 3 60-68 F9.4 mag dm3 []? Differential magnitude 3 69-72 4X --- --- Blank 73-83 D11.5 day HJD4 []? Heliocentric Julian Date 4 84-92 F9.4 mag dm4 []? Differential magnitude 4 -------------------------------------------------------------------------------- Byte-by-byte Description of file: table5.dat -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 1-12 D12.4 day HJD Heliocentric Julian Date 13-19 F7.3 mag dV []? Differential V mag (Var. - Comp.) 20-26 F7.3 mag dR []? Differential R mag (Var. - Comp.) 27-33 F7.3 mag dI []? Differential I mag (Var. - Comp.) 34-40 F7.3 mag dVc []? Differential V mag (Check - Comp.) 41-47 F7.3 mag dRc []? Differential R mag (Check - Comp.) 48-54 F7.3 mag dIc []? Differential I mag (Check - Comp.) -------------------------------------------------------------------------------- ================================================================================ (End) Lee Brotzman [ADS] 28-Sep-1995