کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
1778986 1523744 2015 7 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
The absolute parameters of two W UMa type binaries in Ursa Majoris
موضوعات مرتبط
مهندسی و علوم پایه فیزیک و نجوم نجوم و فیزیک نجومی
پیش نمایش صفحه اول مقاله
The absolute parameters of two W UMa type binaries in Ursa Majoris
چکیده انگلیسی


• Simultaneous Wilson–Devinney analyses of light and radial velocity curves of two W UMa type binaries were performed.
• The orbital and the absolute parameters of the companions in these systems were derived.
• HH UMa was found to be displaying light curve variations due to cool stellar spots.
• The classification of both systems were found as A-subtype.
• The companions of II UMa were found to be slightly evolved subgiants.

We present the results of simultaneous Wilson–Devinney analyses of light and radial velocity curves of two contact binaries in the constellation Ursa Majoris. We found that HH UMa is an A-subtype W UMa binary, which conflicts with the classification of Han et al. (2014) as a W-subtype. Seasonal variations observed in the light curves of the system are well explained with two cool stellar spots in our solution as opposed to the hot-spot based solution by Han et al. (2014), the presence of which would not cause such rapid period variations. The evolutionary status of the system is in agreement with the findings of our study. We modeled II UMa, another A-subtype overcontact binary, without surface spots and found that its both components have rather low surface gravities indicating an advanced state of evolution pointing to evolved subgiants. The high contact degree (f=74%f=74%) supports this viewpoint. Our analysis shows that there is a significant third light contribution, contradicting some of the previous analyses, which lack the detection of the secondary minima as total eclipses because they were not as evident as they are in our light curves.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: New Astronomy - Volume 34, January 2015, Pages 271–277
نویسندگان
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