| Full text | |
| Author(s): |
Draper, Zachary H.
[1]
;
Wisniewski, John P.
[1]
;
Bjorkman, Karen S.
[2]
;
Haubois, Xavier
[3]
;
Carciofi, Alex C.
[3]
;
Bjorkman, Jon E.
[2]
;
Meade, Marilyn R.
[4]
;
Okazaki, Atsuo
[5]
Total Authors: 8
|
| Affiliation: | [1] Univ Washington, Dept Astron, Seattle, WA 98195 - USA
[2] Univ Toledo, Ritter Observ, Dept Phys & Astron, Toledo, OH 43606 - USA
[3] Univ Sao Paulo, Inst Astron Geofis & Ciencias Atmosfer, BR-05508900 Sao Paulo - Brazil
[4] Univ Wisconsin, Space Astron Lab, Madison, WI 53706 - USA
[5] Hokkai Gakuen Univ, Fac Engn, Toyohira Ku, Sapporo, Hokkaido 0628605 - Japan
Total Affiliations: 5
|
| Document type: | Journal article |
| Source: | Astrophysical Journal Letters; v. 728, n. 2 FEB 20 2011. |
| Web of Science Citations: | 14 |
| Abstract | |
We analyze the intrinsic polarization of two classical Be stars in the process of losing their circumstellar disks via a Be to normal B star transition originally reported by Wisniewski et al. During each of five polarimetric outbursts which interrupt these disk-loss events, we find that the ratio of the polarization across the Balmer jump (BJ+/BJ-) versus the V-band polarization traces a distinct loop structure as a function of time. Since the polarization change across the Balmer jump is a tracer of the innermost disk density whereas the V-band polarization is a tracer of the total scattering mass of the disk, we suggest that such correlated loop structures in Balmer jump-V-band polarization diagrams (BJV diagrams) provide a unique diagnostic of the radial distribution of mass within Be disks. We use the three-dimensional Monte Carlo radiation transfer code HDUST to reproduce the observed clockwise loops simply by turning ``on/off{''} the mass decretion from the disk. We speculate that counterclockwise loop structures we observe in BJV diagrams might be caused by the mass decretion rate changing between subsequent ``on/off{''} sequences. Applying this new diagnostic to a larger sample of Be disk systems will provide insight into the time-dependent nature of each system's stellar decretion rate. (AU) | |
| 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 |