S.M. Caballero-Nieves (University of Michigan & Maria Mitchell Obs.), E. Smith (Whitman Coll. & Maria Mitchell Obs.), V. Strelnitski (Maria Mitchell Obs.)
The results of three sessions (June 2003, March 2004 and June 2004) of relative and absolute UBVRI CCD photometry of the eclipsing binary TW CrB, which we carried out with the 31-in reflector of Lowell Observatory, are not in good agreement with the current model of the system (detached, close to filling both Roche lobes). Considerably deeper minima in U than in longer-wavelength bands, as well as considerable U and B excesses off minima (as compared with the adopted spectral class of the system, F8), suggest the presence of at least one hot spot. A preliminary modeling, using the Wilson-Devinney code, shows that the observed difference in the minima depths can, in principle, be explained by a small hot spot at the inner extremity of one of the components. Since the hot spot is, most probably, due to an accretion stream, we suppose that at least one component of TW CrB has already filled its Roche lobe and the system is in an active state of mass exchange. This project was supported by the NSF/REU grant AST-0354056 and the Nantucket Maria Mitchell Association.
Bulletin of the American Astronomical Society, 36 5
© 2004. The American Astronomical Society.