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Abstract

The V light curve of eclipsing binary LD355 was analyzed by using the latest version of Wilson Program in order to derive photometric elements of this system. Since no spectroscopic mass ratio is available, the q‐search method was applied to yield the preliminary range of mass ratio in order to search for the final solution. The solution was performed by assuming detached (mode 2) and semi‐detached (mode 5) configurations, since no classification of the system based on the shape of light curve is possible. The solution in mode 5 leads to an acceptable model. The present solution reveals that LD355 has a photometric mass ratio q = 0.178 and is a semi‐detached binary with the secondary component filling the Roche lobe.

The Period Variation of V839 Oph

“…Taking the total mass (M 1 + M 2 ) of the eclipsing pair to be 1.64 + 0.5 = 2.14 M (Pazhouhesh and Edalati (2002)) and assuming that the orbit of third body is co-planar with the orbit of eclipsing pair we obtained the mass of the hypothetical third body as 0.378 ± 0.022 M . With the Hipparcos distance of V839 Oph d = 123.61 pc, we may easily calculate the maximum angular separation between the third body and eclipsing pair as 0 .073 ± 0 .014.…”

“…The variability and the light curve variation of V839 Oph (BD +9 • 3584, HD166231, V min = 8 m .8, V max = 9 m .39) as W UMa type system were determined by Rigollet (1947). The first photoelectric light curves of this system were obtained by Binnendijk (1960).…”

“…of Astronomy and Space Sciences, TR-34452,Üniversite,İstanbul, Turkey type as F7 V . The first simultaneous radial velocity and light curves solutions of the system were derived by Pazhouhesh and Edalati (2002). With the simultaneous solution, they obtained the absolute parameters of the system and they announced that V839 Oph is an overcontact system which has two stars overfilling their respective Roche lobes.…”

Modeling the 2004.5 Brightening of the Contact Binary V839 Oph

“…Several investigations were made in the past years, giving times of minima and the ephemeris of the system (Binnendijk, 1960;Hilditch and Hill, 1975;Lafta and Grainger, 1985;Agerer and Huebsher, 1997). Niarchos (1989), Akalin and Derman (1997), Pazhouhesh et al (2001) and Pazhouhesh and Edalati (2003) presented a model of the system, based on their observations. Wolf (1996) analyzed in detail the O-C values and concluded that the system undergoes changes of its orbital period, a result also found by Akalin and Derman (1997).…”