Many types of stars show conspicuous emission lines in their optical spectra. These stars are broadly referred to as emission-line stars, but, in the past, they were considered a type of peculiar stars, because emission lines were thought to be an indication of behaviors "peculiar" from the normal stellar atmospheres. Prior to 1950s, early-type emission-line stars such as Wolf-Rayet stars, Be stars, and P Cygni stars were called the early-type peculiar stars. With the advance in theories of emission-line formation, the name "emissionline stars" has been widely adopted to include both early- and late-type stars, and the name of "peculiar-stars" has been only used for chemically peculiar stars. Some stars that have no particular names as emission-line stars, such as cataclysmic variables and Mira variables, are also included in the category of emission-line stars. In closer examination most of stars on the Hertzsprung-Russell (HR) diagram show somehow evidence of emission lines formed in a less-developed form as in case of the Sun. In this book, however, we confine our examination of emission-line stars to the stars having strong lines in the optical region.
Páginas : 537
Peso : 19mb.
Formato : PDF.
Edición : Primera
Año de Publicación :2007
ISBN : 978-0387345000
Editorial : Springer
Autor Tomokazu Kogure, Kam-Ching Leung
0 comentarios:
Publicar un comentario