The Repository @ St. Cloud State

Open Access Knowledge and Scholarship


Streaming Media

Document Type


Publication Date



The red dwarf + white dwarf eclipsing binary V471 Tau shows a variable Hα feature that varies from absorption during eclipse to maximum emission during white dwarf transit. In 1998 we obtained simultaneous BVRI photometry and Hα spectroscopy, with thorough phase coverage of the 12.5 hour orbital period. A binary star model was used with our light curve, radial velocity, and Hα data to refine stellar and orbital parameters. Combined absorption-emission profiles were generated by the model and fit to the observations, yielding a red star radius of 0.94⊙. Orbital inclination 78° is required with this size and other known parameters. The model includes three spots 1,000 K cooler than the surrounding photosphere. The variable Hα profile was modeled as a chromospheric region (essentially on the surface of the red star) centered at the substellar point. Additional emission seen outside our modeled profiles may be large co-rotating prominences that complicate the picture.


Note: This article was originally published as:

Vaccaro, Todd R., and Robert E. Wilson (2002). "Fluorescence and Chromospheric Activity of V471 Tau" in Astronomical Society of the Pacific Conference Series No. 279, Exotic Stars as Challenges to Evolution, IAU Colloquium 187, edited by Christopher A. Tout and Walter van Hamme,

The article was subsequently made available through the SAO/NASA Astrophysics Data System.



To view the content in your browser, please download Adobe Reader or, alternately,
you may Download the file to your hard drive.

NOTE: The latest versions of Adobe Reader do not support viewing PDF files within Firefox on Mac OS and if you are using a modern (Intel) Mac, there is no official plugin for viewing PDF files within the browser window.