LIGHT-CURVE AND PERIOD VARIATIONS OF A W-URSAE MAJORIS SYSTEM LS DELPHINI

DERMAN E., DEMIRCAN O., SELAM S. O.

ASTRONOMY & ASTROPHYSICS SUPPLEMENT SERIES, cilt.90, sa.2, ss.301-309, 1991 (SCI-Expanded) identifier

  • Yayın Türü: Makale / Tam Makale
  • Cilt numarası: 90 Sayı: 2
  • Basım Tarihi: 1991
  • Dergi Adı: ASTRONOMY & ASTROPHYSICS SUPPLEMENT SERIES
  • Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED)
  • Sayfa Sayıları: ss.301-309
  • Anahtar Kelimeler: PHOTOMETRY, STARS-LD DEL, STARS-BINARIES-CLOSE
  • Ankara Üniversitesi Adresli: Evet

Özet

Differential UBV observations, carried out between 1987 and 1989, of a small amplitude W UMa system LS Del = HD 199497 are presented. Light curves and photometric periods of the system are found strongly variable from cycle to cycle. Wavelength-dependent light variations indicate that the system is in a very active phase. We found, by Fourier analysis, that the light variation is dominated by an ellipticity effect but, that about 20% of the variation in B band is due to "reflection". By comparing the light curves we also found evidence that the apparently large "reflection" effect may be induced by a variable emission from a hot region in the neck of the system.