The purpose of this research is to create an accurate simulation of the binary star, Spica, to determine the internal structure of the primary star. A Bayesian Markov Chain Monte Carlo code, called EXOFAST, has been edited and utilized to find the best-fit parameters to describe the orbit of Spica. The specific target for this paper is the derivation of the apsidal period of the star system, which will lead to the derivation of the internal structure of the primary star. Six radial velocity data sets obtained between 1889 and 2000 were analyzed, yielding an apsidal constant of 139.0 ± 6 years, with 68% confidence, which is consistent with the value of Herbison-Evans et. al. (1971), of 124 ± 11 years.
Robinette, Timothy M. and Aufdenberg, Jason
"Refining the Spectroscopic Orbit of the Massive Binary Star Spica,"
McNair Scholars Research Journal: Vol. 2
, Article 6.
Available at: http://commons.erau.edu/mcnair/vol2/iss1/6