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The MACHO Project SMC Variable Star Inventory: I. The Second-overtone Mode of Cepheid Pulsation From First/Second Overtone (1H/2H) Beat Cepheids

The MACHO Collaboration·C. Alcock·R. A. Allsman·D. Alves·T. S. Axelrod·A. C. Becker·D. P. Bennett·K. H. Cook·K. C. Freeman·K. Griest·M. J. Lehner·S. L. Marshall·B. A. Peterson·P. J. Quinn·A. W. Rodgers·A. Rorabeck·W. Sutherland·A. Tomaney·T. Vanderhei
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Abstract

We report the discovery of 20 1H/2H and 7 F/1H beat Cepheids in the SMC by the MACHO Project. We utilize the 20 1H/2H stars to determine lightcurve shape for the SMC second-overtone (2H) mode of Cepheid pulsation. We predict, similar to the findings of Alcock et al. (1997, ApJ, submitted), that 2H Cepheids will have nearly or purely sinusoidal light variations; that the P-L relation for 2H Cepheids will not be distinguishable from the P-L relation for 1H Cepheids within photometric accuracy; and that 2H stars may be discernable from F and 1H stars using the amplitude-period diagram and Fourier parameter progressions for periods P < 0.7 days, our current sample 2H period limit.

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The MACHO Collaboration, C. Alcock, R. A. Allsman, D. Alves, T. S. Axelrod, A. C. Becker, D. P. Bennett, K. H. Cook, K. C. Freeman, K. Griest, M. J. Lehner, S. L. Marshall, B. A. Peterson, P. J. Quinn, A. W. Rodgers, A. Rorabeck, W. Sutherland, A. Tomaney, T. Vanderhei. 1997-09-03. The MACHO Project SMC Variable Star Inventory: I. The Second-overtone Mode of Cepheid Pulsation From First/Second Overtone (1H/2H) Beat Cepheids. https://arxiv.org/abs/astro-ph/9709025

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