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J/AJ/109/1308 H-alpha Emission Variations (Olson+ 1995)
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Rapid H-Alpha Emission Variations in Accretion Disks in Long-Period Algols
Olson E.C., Etzel P.B.
<Astron. J. 109, 1308 (1995)>
=1995AJ....109.1308O
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ADC_Keywords: Binaries, eclipsing ; Equivalent widths
Abstract:
We demonstrate the continuous presence of large variations in
double-peaked H-alpha emission in nine long-period Algol-type
binaries, using recently obtained CCD spectra. Most fluctuations occur
on a time scale <= an orbital period, and a steady state in H-alpha
emission is never reached. In AD Her (P = 10 d), H-alpha emission
dropped in strength more than a factor of five in one seven-day
interval. Contemporary O I lambda 7774 observations showed no
significant changes in oxygen absorption strength or radial velocity
during this time. We tentatively suggest that H-alpha variations arise
from an inner-disk instability, possibly triggered by small
modulations in the mass-transfer rate. This behaviour is reminiscent
of some cataclysmic variables.
Equivalent widths (EW; A) of violet (V) and red (R) H-alpha emission
lobes. Clearly-resolved un-eclipsed V and R lobes are listed; in a few
cases, combined EWs are given. Data deep in primary eclipses are not
listed, because both lobes are partially eclipsed by cool losers. Note
that in a few cases, EWs are measured from 0.9 of continuum level,
because this level yields a better estimate of total hydrogen
emission.
Objects:
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RA (2000) DE Designation(s)
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04 20 17 +42 18.9 RW Per = MWC 731 = HD 276247
05 06 05 +80 14.9 RS Cep = MWC 739
06 00 28 +10 13.1 DN Ori = MWC 788 = HD 40632
06 50 11 +33 14.3 RX Gem = HD 49521
11 13 12 -26 27.9 TT Hya = MWC 860 = HD 97528
18 45 46 +07 13.2 RZ Oph
18 50 00 +20 43.3 AD Her = HD 349425 = CCDM J18500+2043A
20 12 44 +47 23.4 KU Cyg
23 44 54 +45 41.2 WW And
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table.dat 61 385 Equivalent widths and radial velocities
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Byte-by-byte Description of file: table.dat
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Bytes Format Units Label Explanations
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1- 6 A6 --- Name Variable star name
8 A1 --- Flag [*] If emission measured from 0.9 of true
continuum
11- 30 A20 --- UT UT date and time of observation
31- 41 F11.5 d HJD Heliocentric Julian Date of observation
42- 49 F8.5 --- Phase Phase
51- 55 F5.2 0.1nm EW_V ?Equivalent width of violet emission lobe
56 A1 --- u_EW_V *[+:] Uncertainty or combined flag
57- 61 F5.2 0.1nm EW_R ?Equivalent width of red emission lobe
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Note on u_EW_V: the ':' indicates a larger uncertainty on EW_V;
the '+' indicates a simultaneous measurement of violet and red wings.
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Origin: AAS CD-ROM series, Volume 4, 1995 Lee Brotzman [ADS] 04-May-1995
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(End) Revised table.dat by Francois Ochsenbein [CDS] 13-Sep-1996