Contact Binaries



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Contact Binaries

Photoelectric photometry of the contact systems VW Cep, W UMa and AW UMA continue to be carried out at Villanova using the 38-cm telescope. During late 1994 and 1995 light curves of VW Cep were secured by astronomy students Brian Abbott, Brian Pomerance, and by Eastern College student Mark DeVita. Working with Bradstreet and Guinan, DeVita has nearly completed compiling and analyzing the photoelectric photometry obtained at Villanova from 1978 onward. A period study has been done and the light-time effect produced by the tertiary component( P = 30yr) has been successfully modelled and its orbital properties determined. Also, the decrease in the orbital period has been precisely determined and this decrease is in general accord with that expected from angular momentum loss from magnetized winds. After the removal of the effects of the third body and the steady decrease of the orbital period of the eclipsing pair, residuals were found in the O-Cs that appear to be cyclic. These small oscillatory variations in the O-Cs with time-scales of 5-7 yrs may be related to the effects of a dynamo-related activity cycle acting in the close binary. This research is supported by AST 93-15365.



Astronomy
Mon Feb 26 18:11:01 EST 1996