AAS 205th Meeting, 9-13 January 2005
Session 18 Eclipsing Binaries and Contact Binaries
Poster, Monday, January 10, 2005, 9:20am-6:30pm, Exhibit Hall

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[18.09] New Precision CCD Light Curves, Analyses, and Absolute Parameters for the Overcontact Binaries V842 Her and DZ Psc

D. H. Bradstreet, J. R. Hargis, S. J. Sanders (Eastern University)

New V & Rc light curves and the derived absolute parameters are presented for the overcontact systems DZ Psc and V842 Her. These systems were selected for photometric study because the existing radial velocity solutions (Rucinski et al. 1999, 2003) necessitate precision light curves to complete the description of the absolute geometric and orbital parameters. Data were obtained using the 41-cm telescope at the Eastern University Observatory equipped with an SBIG ST-10XME CCD.

DZ Psc (NSV 223; P=0.36613 d) is a low mass ratio, high fillout W-type contact binary with two previously published light curves. We confirm the total nature of the secondary eclipse and find clear evidence of spot activity. The light curve is asymmetric between primary and secondary eclipse, with the level of secondary eclipse exhibiting a definite negative slope. We also find the light curve has changed between the 2003 and 2004 observing seasons; the depth of secondary eclipse has increased by nearly 0.04 mag in R. We will present a new light and radial velocity curve solution using Binary Maker 3 (Bradstreet & Steelman 2002) and Wilson-Devinney and compare this to the solution by Niarchos & Gazeas (2004). A period study, using newly derived and previously existing times of minimum light, will also be presented.

V842 Her (P=0.41903 d) is a W-type contact binary with two previously published light curves. The light curve exhibits a total primary eclipse and slight asymmetries in the maxima due to the presence of spots. A light curve solution has been previously published but no solutions exist that incorporate the mass ratio information from the recent radial velocity data. We present a new light and radial velocity solution using our higher precision V & Rc light curves as well as a period study.

If you would like more information about this abstract, please follow the link to http://caleb.eastern.edu/. This link was provided by the author. When you follow it, you will leave the Web site for this meeting; to return, you should use the Back comand on your browser.

The author(s) of this abstract have provided an email address for comments about the abstract: dbradstr@eastern.edu

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