J/AJ/110/1350 Beta Lyrae light curve changes (Van Hamme+ 1995)
Periodic light curve changes for Beta Lyrae
Van Hamme W., Wilson R.E., Guinan E.F.
<Astron. J. 110, 1350 (1995)>
=1995AJ....110.1350V 1995AJ....110.1350V
ADC_Keywords: Stars, variable ; Photometry
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 38cm
reflector at Villanova (VIL) and the 25cm 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.
Objects:
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RA (2000) DE Designation(s)
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18 36 55.4 +38 46 47 alpha Lyr = HD 172167 = HR 7001
18 50 04.7 +33 21 46 beta Lyr = HD 174638 = HR 7106
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2 23 1246 beta Lyrae Villanova Halpha (wide) observations
table3 23 668 beta Lyrae Villanova Hbeta (wide) observations
table4 23 544 beta Lyrae Villanova Stromgren y observations
table5.dat 54 899 beta Lyrae APT observations
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Byte-by-byte Description of file: table2 table3 table4
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Bytes Format Units Label Explanations
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1- 13 F13.5 d HJD1 Heliocentric Julian Date
16- 22 F7.4 mag dm Differential magnitude
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Byte-by-byte Description of file: table5.dat
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Bytes Format Units Label Explanations
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1- 12 F12.4 d HJD Heliocentric Julian Date
14- 19 F6.3 mag dVmag []? Differential V mag (Var. - Comp.)
21- 26 F6.3 mag dRmag []? Differential R mag (Var. - Comp.)
28- 33 F6.3 mag dImag []? Differential I mag (Var. - Comp.)
35- 40 F6.3 mag dVc []? Differential V mag (Check - Comp.)
42- 47 F6.3 mag dRc []? Differential R mag (Check - Comp.)
49- 54 F6.3 mag dIc []? Differential I mag (Check - Comp.)
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Origin: AAS CD-ROM series, Volume 5, 1995 Lee Brotzman [ADS] 28-Sep-1995
(End) [CDS] 25-Jan-1996