Chromosphere and wind of the Herbig AE star, AB Aurigae

Journal Article · Mon Mar 15 04:00:00 EST 1982 · Astrophys. J.; (United States)

DOI:https://doi.org/10.1086/159776· OSTI ID:5235114

Praderie, F; Talavera, A; Felenbok, P; Czarny, J; Boesgaard, A M

The Herbig Ae variable, AB Aur, has been observed with the CFHT coude spectrograph at 95 mA resolution for five consecutive nights in the blue spectral region and with the IUE satellite in the high resolution, long wavelength mode. The Ca II K line shows an asymmetric and variable profile and shows weak emission in the absorption core at least some of the time. An exceptional event, characterized by the appearance of blue components in Ca II K and Balmer lines, occurred on 1980 October 26. Other evidence of chromospheric emission is the presence of the He I lambda5876, and that of Mg II h and k lines which have striking P Cygni profiles. The Mg II absorption is broader (up to -380 km s/sup -1/) than in the A supergiant ..cap alpha.. Cyg, and shows strong redward emission; the line profiles indicate mass outflow. The Balmer lines (H/sub delta/--H/sub 14/) are in absorption without emission components, in contrast to observations in the 1930s and 1940s. Their measured averaged velocity as well as the Ca II K velocity indicate global motions, variable with time, in the atmosphere. Variability in the line profile shapes and velocities for Ca II K and the Balmer lines occurs on time scales of less than a day. The narrow components of Mg II, Ca-II, and N I which were observed are thought to arise in the nebulosity in which AB Aur is embedded. The characteristic line emission and line positions, breadth, and variabllity show the presence of an active and variable chromosphere with mass outflow.

• Research Organization: Observatoire de Paris-Meudon
• OSTI ID: 5235114
• Journal Information: Astrophys. J.; (United States), Journal Name: Astrophys. J.; (United States) Vol. 254:2; ISSN ASJOA
• Country of Publication: United States
• Language: English

Related Subjects

640102* -- Astrophysics & Cosmology-- Stars & Quasi-Stellar
Radio & X-Ray Sources
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ABSORPTION SPECTRA
ATMOSPHERES
BALMER LINES
CALCIUM IONS
CHARGED PARTICLES
EMISSION SPECTRA
IONS
MAGNESIUM IONS
RADIAL VELOCITY
SPECTRA
STARS
STELLAR ATMOSPHERES
STELLAR WINDS
VARIABLE STARS
VARIATIONS
VELOCITY