Multitechnique Testing of the Viscous Decretion Disk Model. 1. The Stable and Tenuous Disk of the Late-Type Be Star Beta CMi

Klement, R.; Carciofi, A. C.; Rivinius, T.; Panoglou, D.; Vieira, R. G.; Bjorkman, J. E.; Stefl, S.; Tycner, C.; Faes, D. M.; Korcakova, D.

Multitechnique Testing of the Viscous Decretion Disk Model. 1. The Stable and Tenuous Disk of the Late-Type Be Star Beta CMi

Active / Technical Report | Accession Number: ADA628462 |

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Abstract:

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 b 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. 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. 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 3510-5 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 or equal 098, i.e., very close to critical.

Author(s):

Klement, R. ; Carciofi, A. C. ; Rivinius, T. ; Panoglou, D. ; Vieira, R. G. ; Bjorkman, J. E. ; Stefl, S. ; Tycner, C. ; Faes, D. M. ; Korcakova, D.

Author Organization(s):

NAVAL OBSERVATORY FLAGSTAFF AZ

Descriptive Note:

Journal article preprint

Supplementary Note:

Astronomy & Astrophysics manuscript no. aa, October 5, 2015. Prepared in collaboration with Astronomical Institute of Charles University, Charles University in Prague; Instituto de Astronomia, Geof sica e Ciencias Atmosfericas, Universidade de Sao Paulo, Brazil; European Organisation for Astronomical Research in the Southern Hemisphere, Santiago, Chile; Ritter Observatory, University of Toledo, Toledo, OH; and Department of Physics, Central Michigan University, Mount Pleasant, MI. The Navy Precision Optical Interferometer is a joint project of the Naval Research Laboratory and the US Naval Observatory, in cooperation with Lowell Observatory and is funded by the Office of Naval Research and the Oceanographer of the Navy. The original document contains color images.

Pagination:

0037

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DOCUMENT & CONTEXTUAL SUMMARY

Distribution:

Approved For Public Release

Distribution Statement:

Approved For Public Release; Distribution Is Unlimited.

RECORD

Collection: TR

Identifying Numbers

Monitor Series:

USNO/AZ

Subject Terms

Joint Capability Areas:

JCA_6.3.3_Spectrum Management; JCA_6_Net Centric; JCA_6.3_Net Management; JCA_8_Building Partnerships; JCA_8.1_Communicate; JCA_1_Force Support; JCA_5_Command and Control; JCA_5.3_Planning; JCA_1.2_Force Preparation; JCA_1.2.3_Educating; JCA_3.2_Engagement; JCA_3_Force Application; JCA_8.1.1_Inform Domestic and Foreign Audiences; JCA_8.1.3_Influence Adversary and Competitor Audiences; JCA_1.4_Force Support; JCA_1.2.5_Lessons Learned; JCA_3.2.1_Kinetic Means; JCA_6.1.2_Wireless Transmission; JCA_6.1_Information Transport; JCA_1.3_Human Capital Management; JCA_1.4.2_Health Service Delivery

Modernization Areas:

Space

Communities of Interest:

Sensors

Descriptor(s):

*B TYPE STARS, EMISSION SPECTRA, INTERFEROMETRY, MODELS, POLARIMETRY

Field(s)/Group(s):

Astrophysics

Keyword(s):

BE STARS, RADIO CONTINUUM, *VDD(VISCOUS DECRETION DISK)

Report Date:

2015 Oct 05

Creation Date:

2016 Mar 30