A photometric monitoring of bright high-amplitude δ Scuti stars: II. Period updates for seven stars

A. Derekas, L. L. Kiss, P. Székely, E. J. Alfaro, B. Csák, Sz Mészáros, E. Rodríguez, A. Rolland, K. Sárneczky, Gy M. Szabó, K. Szatmáry, M. Váradi, Cs Kiss

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We present new photometric data for seven high-amplitude δ Scuti stars. The observations were acquired between 1996 and 2002, mostly in the Johnson photometric system. For one star (GW UMa), our observations are the first since the discovery of its pulsational nature from the Hipparcos data. The primary goal of this project was to update our knowledge on the period variations of the target stars. For this, we have collected all available photometric observations from the literature and constructed decades-long O - C diagrams of the stars. This traditional method is useful because of the single-periodic nature of the light variations. Text-book examples of slow period evolution (XX Cyg, DY Her, DY Peg) and cyclic period changes due to light-time effect (LITE) in a binary system (SZ Lyn) are updated with the new observations. For YZ Boo, we lind a period decrease instead of increase. The previously suggested LITE-solution of BE Lyn (Kiss & Szatmáry 1995) is not supported with the new O - C diagram. Instead of that, we suspect the presence of transient light curve shape variations mimicking small period changes.

Original languageEnglish
Pages (from-to)733-743
Number of pages11
JournalAstronomy and Astrophysics
Issue number2
Publication statusPublished - Jan 1 2003



  • Stars: oscillations
  • Stars: variables: general
  • δ Sct

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science

Cite this

Derekas, A., Kiss, L. L., Székely, P., Alfaro, E. J., Csák, B., Mészáros, S., Rodríguez, E., Rolland, A., Sárneczky, K., Szabó, G. M., Szatmáry, K., Váradi, M., & Kiss, C. (2003). A photometric monitoring of bright high-amplitude δ Scuti stars: II. Period updates for seven stars. Astronomy and Astrophysics, 402(2), 733-743. https://doi.org/10.1051/0004-6361:20030291