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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

Multitechnique testing of the viscous decretion disk model I. The stable and tenuous disk of the late-type Be star beta CMi

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Klement, R. [1] ; Carciofi, A. C. [2] ; Rivinius, Th. [3] ; Panoglou, D. [2] ; Vieira, R. G. [2] ; Bjorkman, J. E. [4] ; Stefl, S. ; Tycner, C. [5] ; Faes, D. M. [2] ; Korcakova, D. [1] ; Mueller, A. [3] ; Zavala, R. T. [6] ; Cure, M. [7]
Total Authors: 13
[1] Charles Univ Prague, Astron Inst Charles, CR-18000 Prague 8 - Czech Republic
[2] Univ Sao Paulo, Inst Astron Geofis & Ciencias Atmosfer, BR-05508900 Sao Paulo, SP - Brazil
[3] European Org Astron Res Southern Hemisphere, Santiago 19 - Chile
[4] Univ Toledo, Dept Phys & Astron, Ritter Observ, Toledo, OH 43606 - USA
[5] Cent Michigan Univ, Dept Phys, Mt Pleasant, MI 48859 - USA
[6] US Naval Observ, Flagstaff, AZ 86001 - USA
[7] Univ Valparaiso, Fac Ciencias, Inst Fis & Astron, Valparaiso 5030 - Chile
Total Affiliations: 7
Document type: Journal article
Source: Astronomy & Astrophysics; v. 584, DEC 2015.
Web of Science Citations: 13

Context. The viscous decretion disk (VDD) model is able to explain most of the currently observable properties of the circumstellar disks of Be stars. However, more stringent tests, focusing on reproducing multitechnique observations of individual targets via physical modeling, are needed to study the predictions of the VDD model under specific circumstances. In the case of nearby, bright Be star beta CMi, these circumstances are a very stable low-density disk and a late-type (B8Ve) central star. Aims. The aim is to test the VDD model thoroughly, exploiting the full diagnostic potential of individual types of observations, in particular, to constrain the poorly known structure of the outer disk if possible, and to test truncation effects caused by a possible binary companion using radio observations. Methods. We use the Monte Carlo radiative transfer code HDUST to produce model observables, which we compare with a very large set of multitechnique and multiwavelength observations that include ultraviolet and optical spectra, photometry covering the interval between optical and radio wavelengths, optical polarimetry, and optical and near-IR (spectro) interferometry. Results. A parametric VDD model with radial density exponent of n = 3.5, which is the canonical value for isothermal flaring disks, is found to explain observables typically formed in the inner disk, while observables originating in the more extended parts favor a shallower, n = 3.0, density falloff. Theoretical consequences of this finding are discussed and the outcomes are compared with the predictions of a fully self-consistent VDD model. Modeling of radio observations allowed for the first determination of the physical extent of a Be disk (35(-5)(+10) stellar radii), which might be caused by a binary companion. Finally, polarization data allowed for an indirect measurement of the rotation rate of the star, which was found to be W greater than or similar to 0.98, i.e., very close to critical. (AU)

FAPESP's process: 09/54006-4 - A computer cluster for the Astronomy Department of the University of São Paulo Institute of Astronomy, Geophysics and Atmospheric Sciences and for the Cruzeiro do Sul University Astrophysics Center
Grantee:Elisabete Maria de Gouveia Dal Pino
Support type: Multi-user Equipment Program
FAPESP's process: 12/20364-4 - Beyond dust survival: the inner regions of protoplanetary disks
Grantee:Rodrigo Georgetti Vieira
Support type: Scholarships in Brazil - Post-Doctorate
FAPESP's process: 13/16801-2 - Modelling the formation and evolution of inflowing and outflowing gaseous disks around stars
Grantee:Despina Panoglou
Support type: Scholarships in Brazil - Post-Doctorate
FAPESP's process: 10/19060-5 - An interferometric view on hot star disks
Grantee:Daniel Moser Faes
Support type: Scholarships in Brazil - Doctorate