A Parameter Study of Classical Be Star Disk Models Constrained by Optical Interferometry

We have computed theoretical models of circumstellar disks for the classical Be stars κ Dra, β Psc, and υ Cyg. Models were constructed using a non-LTE radiative transfer code developed by Sigut & Jones (2007), which incorporates a number of improvements over previous treatments of the disk thermal structure, including a realistic chemical composition. Our models are constrained by direct comparison with long-baseline optical interferometric observations of the Hα-emitting regions and by contemporaneous Hα line profiles. Detailed comparisons of our predictions with Hα interferometry and spectroscopy place very tight constraints on the density distributions for these circumstellar disks.

[1]  M. Fleming.  Stars having Peculiar Spectra. Group of Stars of the Fifth Type in Cepheus , 1891 .

[2]  W. W. Campbell.  Stars whose spectra contain both bright and dark hydrogen lines. , 1895 .

[3]  O. Struve.  On the Origin of Bright Lines in Spectra of Stars of Class B , 1931 .

[4]  WAVELENGTH DEPENDENCE OF POLARIZATION. XVII. BE-TYPE STARS. , 1969 .

[5]  G. Peters.  An analysis of the far-ultraviolet spectra of the pole-on Be stars Upsilon Cygni and Mu Centauri , 1979 .

[6]  Gordon L. Olson,et al.  Short characteristic solution of the non-LTE line transfer problem by operator perturbation—II. The two-dimensional planar slab , 1987 .

[7]  R. Kurucz.  ATLAS9 Stellar Atmosphere Programs and 2 km/s grid. , 1993 .

[8]  J. Porter.  ON THE ROTATIONAL VELOCITIES OF BE AND BE-SHELL STARS , 1996 .

[9]  J. Armstrong,et al.  The Navy Prototype Optical Interferometer , 1998 .

[10]  ApJ, in press , 1999 .

[11]  A. Cox,et al.  Allen's astrophysical quantities , 2000 .

[12]  Be-star rotation: how close to critical? , 2003, astro-ph/0312113.

[13]  David Mozurkewich,et al.  A Method for Internal Calibration of Optical Interferometer Data and Application to the Circumstellar Envelope of γ Cassiopeiae , 2003 .

[14]  J. Porter,et al.  Classical Be Stars , 2003, 1310.3962.

[15]  S. Owocki.  Rotation and Mass Ejection: the Launching of Be-Star Disks (Invited Review) , 2004 .

[16]  PHYSICAL PARAMETERS OF SOUTHERN B- AND Be-TYPE STARS , 2004 .

[17]  Properties and nature of Be stars. XXIII. Long-term variations and physical properties of x Dra , 2004, astro-ph/0401491.

[18]  E. K. Baines,et al.  First Results from the CHARA Array. I. An Interferometric and Spectroscopic Study of the Fast Rotator α Leonis (Regulus) , 2005 .

[19]  C. Neiner,et al.  Rotation, pulsations and outbursts in the Be star υ Cygni (HD 202904) , 2005 .

[20]  S. Cranmer.  A Statistical Study of Threshold Rotation Rates for the Formation of Disks around Be Stars , 2005, astro-ph/0507718.

[21]  O. Chesneau,et al.  First VLTI/MIDI observations of a Be star: Alpha arae , 2005, astro-ph/0501162.

[22]  J. T. Armstrong,et al.  Constraining Disk Parameters of Be Stars using Narrowband Hα Interferometry with the Navy Prototype Optical Interferometer , 2006 .

[23]  Non-LTE Monte Carlo Radiative Transfer. I. The Thermal Properties of Keplerian Disks around Classical Be Stars , 2005, astro-ph/0511228.

[24]  Jr.,et al.  CHARA Array K'-Band Measurements of the Angular Dimensions of Be Star Disks , 2006, astro-ph/0609501.

[25]  C. E. Jones,et al.  The Thermal Structure of the Circumstellar Disk Surrounding the Classical Be Star γ Cassiopeiae , 2007, 0706.4036.