Speaker
Description
The VERITAS Collaboration has performed stellar intensity interferometry analysis on the binary system Spica, based on data accumulated over a period of five years. Extended observations with six indepdendent baselines provided good coverage of the Fourier (u,v) plane with high signal-to-noise. The intensity pattern was measured over several cycles of the 4.01-day orbit and is well reproduced by a simple model that allows extraction of all orbital parameters with improved precision over previous measurements. We compare our results with those of Hanbury Brown (1971), with some focus on the so-called "ellipticity problem." We find that our orbital parameters are consistent with recent measurements of radial velocity (RV) curves. Combining SII and RV measurements provides stronger constraints on the orbital parameters and a more precise determination of the apsidial motion constant (a.k.a. internal structure constant). We compare our observations with complete stellar models to extract fundamental stellar parameters.
