at Tarleton State University: A study of Eclipsing Binary (WY TAU) in the of Taurus the Bull Avery McChristian Advisor: Dr Shaukat Goderya

Types of Eclipsing Binary What is a Observation and Analysis A binary star is a stellar system consisting of two stars which The data on “WY TAU” was gathered in November and orbit around a common point, called the center of mass. The December of 2006 using Tarleton State’s observatory. two stars are gravitationally bound to each other. It has been Contact 1,008 images were collected over nine . The estimated that more than half of all stars in our are images were taken under two different filters; 507 were binary stars. Binary stars play a vital role in our taken using a Visual band pass filter and 501 were understanding of the evolution and physics of stars. When taken using a Blue band pass filter. Using “Astronomical studied they can provide important data on the mass of each Image Processing for Windows” software we were able individual star. It is possible to obtain this information only if Semi Detached to extract the Julian date and from the raw both spectroscopic and photometric study of the system is images. We then used excel to convert time, or Julian performed. Spectroscopic study enables the determination of date, into phase and magnitude into intensity. Using the absolute parameters of the binary system. phase and intensity figures we were able to construct the observed curve. Upon inspection of the light curve we realized the period and epoch needed Detached corrections. Therefore we found the new epoch and Why Study Eclipsing Binary period using the middle line method and the regression Stars analysis.

In order to determine the absolute parameters using Source: Starlight Pro V & B Light Curves spectroscopic techniques, one needs information on the inclination of the orbit. In a binary system the components are so close to each other that they cannot be identified visually. WY TAU Epoch: 2454084.6100 However, since the orbital plane is oriented edge wise to our line of sight, we see the two star as eclipses in the light Period 0.6929794 days curve. By studying the light curve through photometric WY TAU is a poorly studied eclipsing binary system. Our technique one can get information on the inclination of the initial analysis show it to be a contact system. system. Visual band pass Light Curve Blue band pass Light Curve

Photometryr = [(k1+k2) → / w]ω & i

sin(i)Spectroscopy → k1 & k2 From: SIMBAD and ALADIN From: SIMBAD and ALADIN From: Binary Intensity Intensity

(m1+m2) = Maker Intensity w2r3r = [(k 1/+k G2) / ω] sin (i) m2/m1=k1/k2 Ongoing work -0.5 0 0.5 1 1.5 2 3 -0.3 0.2 0.7 1.2 (M1+M2) = ω r / G Phase Phase As we continue our research we hope to compute a M2 / M1 = k1 / k2 photometric solution using a Wilson-Devinney Acknowledgement: This research is funded by (mathematical) model. Tarleton State University Research Grant