HDUST inhales He: probing the hotter inner parts of gaseous disks by the inclusion...
Probing the physical characteristics of the disks surrounding Be stars
| Full text | |
| Author(s): |
Carciofi, Alex C.
[1]
;
Bjorkman, Jon E.
[1, 2]
;
Otero, Sebastian A.
[3]
;
Okazaki, Atsuo T.
[4]
;
Stefl, Stanislav
[5]
;
Rivinius, Thomas
[5]
;
Baade, Dietrich
[6]
;
Haubois, Xavier
[1]
Total Authors: 8
|
| Affiliation: | [1] Univ Sao Paulo, Inst Astron Geofis & Ciencias Atmosfer, BR-05508900 Sao Paulo - Brazil
[2] Univ Toledo, Dept Phys & Astron, Ritter Observ, Toledo, OH 43606 - USA
[3] Amer Assoc Variable Star Observers, Cambridge, MA 02138 - USA
[4] Hokkai Gakuen Univ, Fac Engn, Toyohira Ku, Sapporo, Hokkaido 0628605 - Japan
[5] European Org Astron Res So Hemisphere, Santiago 19 - Chile
[6] European Org Astron Res So Hemisphere, D-85748 Garching - Germany
Total Affiliations: 6
|
| Document type: | Journal article |
| Source: | Astrophysical Journal Letters; v. 744, n. 1 JAN 1 2012. |
| Web of Science Citations: | 47 |
| Abstract | |
Be stars possess gaseous circumstellar decretion disks, which are well described using standard alpha-disk theory. The Be star 28 CMa recently underwent a long outburst followed by a long period of quiescence, during which the disk dissipated. Here we present the first time-dependent models of the dissipation of a viscous decretion disk. By modeling the rate of decline of the V-band excess, we determine that the viscosity parameter alpha = 1.0 +/- 0.2, corresponding to a mass injection rate (M) over dot = (3.5 +/- 1.3) x 10(-8) M-circle dot yr(-1). Such a large value of a suggests that the origin of the turbulent viscosity is an instability in the disk whose growth is limited by shock dissipation. The mass injection rate is more than an order of magnitude larger than the wind mass-loss rate inferred from UV observations, implying that the mass injection mechanism most likely is not the stellar wind, but some other mechanism. (AU) | |
| FAPESP's process: | 10/19029-0 - 3D radiative transfer models: bridging theory and observations |
| Grantee: | Alex Cavaliéri Carciofi |
| Support Opportunities: | Regular Research Grants |
| FAPESP's process: | 10/16037-2 - 3D NLTE radiative transfer models for testing circumstellar disk physics |
| Grantee: | Alex Cavaliéri Carciofi |
| Support Opportunities: | Research Grants - Visiting Researcher Grant - International |
| FAPESP's process: | 09/07477-1 - Probing atmospheres and circumstellar environments of Be stars and evolved low mass stars with interferometry and polarimetry |
| Grantee: | Xavier Marie Alain Haubois |
| Support Opportunities: | Scholarships in Brazil - Post-Doctoral |