Investigation of orbital period variations of two low mass ratio contact binary stars: V404 Peg and V619 Peg

Abstract

In this study the period variations of two over contact systems with low mass ratio are examined in detail for the first time. Period analyses of the systems are performed using the O-C method with their all minima times collected from the databases and published papers. The O-C diagram of V404 Peg shows a downward parablic trend, and it is found that its period has a secular decrease at a rate of 9.3(5) x10-2 s/yr. The O-C diagram of V619 Peg shows an upward parabolic+cyclical character which indicates a continuous increase at a rate of 6.3(1)x10-2 s/yr in the system’s orbital period. The cyclical period variation is discussed according to a possible third companion and Applegate mechanism.

Keywords

• Contact binary stars,period analysis,V404 Peg,V619 Peg

Düşük kütle oranlı iki değen çift yıldızın yörünge dönemi değişimlerinin incelenmesi: V404 Peg ve V619 Peg

Abstract

Bu çalışmada düşük kütle oranına sahip iki aşırı değen çift yıldızın yörünge dönemi değişimleri, detaylı olarak ilk kez incelenmiştir. Hedef sistemlerin dönem analizleri, veri tabanlarından ve literatür yayınlarından alınan minimum ışık zamanları kullanılarak O-C yöntemine göre yapılmıştır. V404 Peg’in O-C diyagramının aşağı parabol şeklinde bir yapı gösterdiği ve döneminin 9.3(5)x10-2 s/yıl oranında azaldığı bulunmuştur. V619 Peg’in O-C diyagramının parabol+çevrimsel yapı gösterdiği ve döneminin 6.3(1)x10-2 s/yıl oranında arttığı bulunmuş; çevrimsel dönem değişimi, olası üçüncü cisme ve Applegate mekanizmasına göre tartışılmıştır.

Keywords

• Değen çift yıldızlar,dönem analizi,V404 Peg,V619 Peg

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