A Study of the Nature of Herbig Ae/Be Companion Stars

Advisors: Bernadette Rodgers, Sandrine Thomas, Nicole van der Bliek

Classified by George Herbig in 1960, Herbig Ae/Be stars are pre-main-sequence (PMS), intermediate-mass stars with circum-stellar accretion disks. They are the higher-mass counterpart to T Tauri stars. Many Herbig stars have been found to form in binary or multiple groups with one or more low-mass companions, generally assumed to be T Tauris. The disks surrounding these stars (Herbigs and T Tauris) create an excess in the infrared flux. In recent research (Leinert et al (1997), Bouvier & Corporon (2001)) many companions to Herbig stars have been resolved and studied. The surprising outcome of this research is that the companions to many of these Herbig stars have little to none of the expected infrared excess. In some cases, even the primary (Herbig) star lacks infrared excess. This implies that the disks of these stars have been prematurely removed. Are the companions to these Herbig stars not classical T Tauri stars as previously believed? Or have they just lost their disks prematurely? These are questions driving this project.

References:
Bouvier, J., Corporon, P. 2001, IAUS, 200, 155
Leinert, C., Richichi, A. & Haas, M. 1997, A&A, 318, 472