Preliminary modeling of VY CMa
23 June 2008

Dust cross section (70% C, 30% Si): cross_section_0.7C+0.3Si.dat
Stellar temperature = 3500 K
Dust sublimation temperature = 1500 K
Dust density structure ∝ x-2exp(-10z2/x3)
Radial optical depth in the equatorial plane at 0.55mic = 100
Outer dust density radius = 100 sublimation radii


Sketch of the dust envelope structure. The surface is defined as radial tau=1.

Results

SED fit

Bolometric flux = 5E9 W/m2
This gives stellar size of ~10mas
Dust sublimation radius = 7 stelar radii ~ 35mas
Theoretical images are given in units of sublimation radii


NIR images (without proper position angle and PSF convolution)


NIR image (without proper position angle and PSF convolution)


HST images

Overlay of HST images and theoretical models

NIR images

MIR images

Next modeling steps

- reduce stellar temperature
- increase the SiO dust fraction
- make the polar cavities more narrow to get better images
- increase outer dust radius slightly