SIMBAD references

2011ApJ...728L..40D - Astrophys. J., 728, L40 (2011/February-3)

A new diagnostic of the radial density structure of Be disks.

DRAPER Z.H., WISNIEWSKI J.P., BJORKMAN K.S., HAUBOIS X., CARCIOFI A.C., BJORKMAN J.E., MEADE M.R. and OKAZAKI A.

Abstract (from CDS):

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.

Abstract Copyright:

Journal keyword(s): circumstellar matter - stars: individual (pi Aquarii, 60 Cygni)

Simbad objects: 5

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