Properties and Evolution of Disks around Pre-Main-Sequence Stars of Intermediate Mass
Abstract
This chapter discusses the properties of the immediate circumstellar environment of pre-main-sequence stars of intermediate mass, or Herbig Ae/Be (HAeBe) stars, with particular emphasis on the properties and evolution of the circumstellar disks. HAeBe stars cover a large range of spectral types and luminosities; this variety has implications for their environments, which, by the time a star becomes optically visible, are very different in early B stars (HBe≥5 Msun) and in stars of later spectral types (HAe≤5 Msun). A variety of recent infrared and millimeter observations are reviewed. They indicate that HBe stars generally lack clear evidence of disks and are often found inside large cavities, depleted of dust and gas. We interpret these observations as evidence of a rapid evolution of the circumstellar environment, possibly caused by the strong stellar radiation fields. In contrast, circumstellar disks appear to be associated with a large number of cataloged HAe stars. We discuss the properties and evolution of these disks within the context of possible grain growth and planet formation.
- Publication:
-
Protostars and Planets IV
- Pub Date:
- May 2000
- Bibcode:
- 2000prpl.conf..559N