¹ Space Sciences Center, University of Southern California, Los Angeles, CA 90089-1341, USA
² CHARA, Dept. of Physics \& Astronomy, Georgia State University, Atlanta, GA 30303-3083, USA

Current information on the nature of the HR 2142 system is presented. The circumstellar material (CSM) including the mass flow toward and away from the mass-gaining B star has been studied from ~100 IUE SWP HIRES images obtained from 1979-95 and ground-based CCD data from KPNO acquired between 1985-2001. The strength and velocity behavior of the infall components to the UV SiII lines seen during the primary shell phase (PSP) from ~0.70-0.98 resembles that observed in conventional Algol systems, but the inferred mass infall rate is too small to account for the massive H-emitting disk about the B primary. The cause for the mass outflow observed during the secondary shell phase (SSP) remains unknown, but a localized plasma that has been identified from phase-dependent variations in the emission component to HeI 6678 may be part of the SSP phenomenon. Although the secondary remains undetected in the optical/IR spectral regions, UV data currently do not yield strong support for the presence of an O subdwarf as in the  Per system. HR 2142 may represent an earlier evolutionary stage of  Per and a possibly similar Be binary 59 Cyg.

in Exotic Stars as Challenges to Evolution, IAU Colloquium 187, ed C. A. Tout, C. A. & W. Van Hamme, ASP Conference Series 279, 149
Preprints from gjpeters@mucen.usc.edu