uvby — β photometry of the RR Lyrae star AC And

 

J. H. Peña¹, R. Peniche^1,4, M. A. Hobart², C. de la Cruz², and A. A. Gallegos³

 

¹ Instituto de Astronomía, UNAM, Apdo. Postal 70-264, 04510 México, D. F., México (jhpena@astroscu.unam.mx).

² Universidad Veracruzana, Facultad de Física, Apdo. Postal 270, Xalapa, Ver., México (mhobart@xaLmegared.net.mx).

³ Universidad Autónoma Metropolitana, México, D. F., México.

⁴ Deceased.

 

Received, 2001 November 7
Accepted 2005 June 22

 

RESUMEN

Se presenta tanto fotometría diferencial como Strömgren uvby — β de la estrella AC And. Del análisis de estos datos, así como de los de la literatura, se corroboran los períodos propuestos por Fitch & Szeidl (1976). La fotometría de Strömgren se ha utilizado para la determinación del enrojecimiento y de los parámetros físicos log g y logT_e así como la metalicidad [Fe/H]. Se discute la determinación de M_v y, en base a los resultados, proponemos a AC And como una estrella del tipo RR de Lira de posible composición química anormal.

 

ABSTRACT

Strömgren uvby — β and differential V photoelectric photometry of the variable star AC And is presented. Analysis of this data, as well as data from the literature, corroborates the periods proposed by Fitch & Szeidl (1976). Strömgren photometry has been used for the determination of the reddening and the physical parameters log g and logT_e, as well as the metallicity [Fe/H]. The determination of M_v is also discussed and, in view of the results, we propose that AC And is an RR Lyrae star with possible anomalous chemical composition.

Key Words: Stars: Variables: Delta scuti — Stars: Variables: RR Lyrae — Techniques: Photometric.

 

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ACKNOWLEDGMENTS

We would like to thank the staff of the OAN who made the observations possible. J. Miller and J. Orta did the proofreading and typing, respectively. A. Diaz and C. Guzmán assisted at the computer. Recognition is gratefully given to R. Peña Miller who pointed out a needed correction; to M. Paparo who suggested the observation of this star, to L. Parrao for fruitful discussions; to V. Kameyama for his enthusiasm in capturing Guman's data; and to A. Pani for his assistance in the 1998 season. MAH and CdC thank the hospitality of the IA-UNAM, Mexico and RP and JHP that of the IAA, Spain. AAG thanks the Universidad Tecnológica de la Mixteca. This work was partially supported by the following sources: CONACYT in a collaboration program with the Hungarian Academy of Sciences; E130.1451 and Papiit IN100199 and IN110102. JHP thanks DGAPA for the funds provided for a sabbatical leave and to Dr. P. Lampens and the Koninklijke Ster-renwacht van Belgie and to Dr. E. Michel and the Observatoire de Paris-Meudon, France for their hospitality while this work was concluded. The comments and remarks of an anonymous referee certainly improved this Paper. This article has made use of the SIMBAD database operated at CDS, Strasbourg, France and ADS, NASA Astrophysics Data Systems hosted by Harvard-Smithsonian Center for Astrophysics.

 

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