scholarly journals The FeII λ5317 line profile of nine Be stars

1994 ◽  
Vol 162 ◽  
pp. 263-264
Author(s):  
D. Ballereau ◽  
J. Chauville ◽  
J. Zorec
Keyword(s):  

Our aim is to analyze the FeII λ5317 emission line of nine Be stars recorded in 1990, to deduce some constraints on the modeling of their envelope and to compare them to the results obtained in 1985 and 1987 by other authors.

1987 ◽  
Vol 92 ◽  
pp. 84-86
Author(s):  
D. R. Gies ◽  
David McDavid

Evidence is now accumulating that many Be stars display photospheric line profile variations on timescales of days or less that are probably caused by nonradial pulsations (Baade 1984; Penrod 1986). In some circumstances these pulsations can promote mass loss into the circumstellar envelope, and consequently the conditions in the inner part of the envelope may vary on similar timescales. Changes in the envelope could produce variations in the polarization and emission line profiles, and observers have reported rapid variability in both. We describe here an initial attempt to search for simultaneous variations in continuum polarization, Hα emission, and the He I λ6678 photospheric absorption line in order to investigate correlated changes on short timescales.


1994 ◽  
Vol 162 ◽  
pp. 89-99
Author(s):  
Douglas R. Gies

The periodic variations in the photospheric lines of Be stars could result from rotation or nonradial pulsations (NRP). Here I review the spectroscopic results on ten Be stars which have been targeted in recent multiwavelength campaigns. Most of the stars display variability consistent with an l = –m = 2 NRP mode with periods on the order of a day, and the associated light curves are consistent with the pulsation periods, amplitudes, and phases derived from spectroscopy. The variability is strongest in the line wings which only agrees with the NRP prediction that horizontal motions should exceed vertical motions for g-mode pulsations. High frequency, non-periodic variations are also observed, but I argue that these are of circumstellar origin and do not represent high-order NRP. The NRP periods are also found in variations of the Hβ emission line but these probably result from photospheric and not disk variations. However, the same periods occur in the C IV λ1550 P Cygni line, which strongly suggests that NRP modulates the local stellar wind.


1998 ◽  
Vol 116 (1) ◽  
pp. 455-468 ◽  
Author(s):  
James Muzerolle ◽  
Lee Hartmann ◽  
Nuria Calvet

Author(s):  
Suk Yee Yong ◽  
Rachel L. Webster ◽  
Anthea L. King ◽  
Nicholas F. Bate ◽  
Matthew J. O’Dowd ◽  
...  

AbstractThe structure and kinematics of the broad line region in quasars are still unknown. One popular model is the disk-wind model that offers a geometric unification of a quasar based on the viewing angle. We construct a simple kinematical disk-wind model with a narrow outflowing wind angle. The model is combined with radiative transfer in the Sobolev, or high velocity, limit. We examine how angle of viewing affects the observed characteristics of the emission line. The line profiles were found to exhibit distinct properties depending on the orientation, wind opening angle, and region of the wind where the emission arises.At low inclination angle (close to face-on), we find that the shape of the emission line is asymmetric, narrow, and significantly blueshifted. As the inclination angle increases (close to edge-on), the line profile becomes more symmetric, broader, and less blueshifted. Additionally, lines that arise close to the base of the disk wind, near the accretion disk, tend to be broad and symmetric. Single-peaked line profiles are recovered for the intermediate and equatorial wind. The model is also able to reproduce a faster response in either the red or blue sides of the line profile, consistent with reverberation mapping studies.


1994 ◽  
Vol 212 (1-2) ◽  
pp. 107-114 ◽  
Author(s):  
C. A. Grady ◽  
M. R. P�rez ◽  
P. S. Th�

2021 ◽  
Vol 919 (2) ◽  
pp. 73
Author(s):  
Justin A. Kader ◽  
Liese van Zee ◽  
Kristen B. W. McQuinn ◽  
Laura C. Hunter

Sign in / Sign up

Export Citation Format

Share Document