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J/AJ/107/679                     AH Cam                      (Silbermann+, 1994)

AH Cam: a metal-rich RR Lyrae star with the shortest known Blazhko period SMITH H.A., MATTHEWS J.M., LEE K.M., WILLIAMS J., SILBERMANN N.A., BOLTE M. <Astron. J. 107, 679 (1994)> =1994AJ....107..679S (SIMBAD/NED Reference)
ADC_Keywords: Stars, variable; Stars, peculiar; Photometry, CCD Abstract: Analysis of 746 new V-band observations of the RR Lyrae star AH Cam obtained during 1989-1992 clearly show that its light curve cannot be described by a single period. In fact, at first glance, the Fourier spectrum of the photometry resembles that of a double-mode pulsator, with peaks at a fundamental period of 0.3686d and an apparent secondary period of 0.2628d. Nevertheless, the dual-mode solution is a poor fit to the data. Rather, we believe that AH Cam is a single-mode RR Lyrae star undergoing the Blazhko effect: periodic modulation of the amplitude and shape of its light curve. What was originally taken to be the period of the second mode is instead the 1-cycle/d alias of a modulation sidelobe in the Fourier spectrum. The data are well described by a modulation period of just under 11d, which is the shortest Blazhko period reported to date in the literature and confirms the earlier suggestion by Goranskii. A low-resolution spectrum of AH Cam indicates that it is relatively metal rich, with {DELTA}S≤2. Its high metallicity and short modulation period may provide a critical test of at least one theory for the Blazhko effect. Moskalik's internal resonance model makes specific predictions of the growth rate of the fundamental mode vs fundamental period. AH Cam falls outside the regime of other known Blazhko variables and resonance model predictions, but these are appropriate for metal-poor RR Lyrae stars. If the theory matches the behavior of AH Cam for a metal-rich stellar model, this would bolster the resonance hypothesis. Addresses: Smith H.A. Department of Physics & Astronomy, Michigan State University, East Lansing, Michigan 48824 Matthews J.M. Department of Geophysics & Astronomy, University of British Columbia, Vancouver, B.C. V6T 1Z4, Canada and Departement de physique et Observatoire du Mont Megantic, Universite de Montreal, Montreal, Quebec H3C 3J7, Canada Lee K.M., Williams J., and Silbermann N.A. Department of Physics & Astronomy, Michigan State University, East Lansing Michigan 48824 Bolte M. Hubble Fellow, NASA/ST ScI, UCO/Lick Observatory, University of California, Santa Cruz, California 95064 File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file table1 18 423 1989-1990 AH Cam CCD photometry
Byte-by-byte Description of file: table1
Bytes Format Units Label Explanations
1- 11 F11.3 d HJD Heliocentric Julian Date (1) 14- 18 F5.2 mag Vmag V magnitude (2)
Note (1): Heliocentric Julian Date of midexposure. Note (2): Based on the scatter in the comparison-check star data, each observation of AH Cam is accurate to about ± 0.025 mag.
Origin: AAS CD-ROM series, Volume 2, 1994
(End) Lee Brotzman [ADS] 19-Apr-1994, Patricia Bauer [CDS] 19-Oct-1994
The document above follows the rules of the Standard Description for Astronomical Catalogues.From this documentation it is possible to generate f77 program to load files into arrays or line by line

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