The Outer Disk of the Classical Be Star ψ Per
To this date ψ Per is the only classical Be star that was angularly resolved in radio (by the VLA at λ = 2 cm). Gaussian fit to the azimuthally averaged visibility data indicates a disk size (FWHM) of ~500 stellar radii (Dougherty & Taylor 1992). Recently, we obtained new multi-band cm flux density measurements of ψ Per from the enhanced VLA. We modeled the observed spectral energy distribution (SED) covering the interval from ultraviolet to radio using the Monte Carlo radiative transfer code HDUST (Carciofi & Bjorkman 2006). An SED turndown, that occurs between far-IR and radio wavelengths, is explained by a truncated viscous decretion disk (VDD), although the shallow slope of the radio SED suggests that the disk is not simply cut off, as is assumed in our model. The best-fit size of a truncated disk derived from the modeling of the radio SED is 100+5 −15 stellar radii, which is in striking contrast with the result of Dougherty & Taylor (1992). The reasons for this discrepancy are under investigation.
Klement, Robert; Carciofi, Alex C.; Rivinius, Thomas; Matthews, Lynn D.; Ignace, Richard; Bjorkman, Jon E.; Vieira, Rodrigo G.; Mota, Bruno C.; Faes, Daniel M.; and Stefl, Stanislav. 2016. The Outer Disk of the Classical Be Star ψ Per. Proceedings of the International Astronomical Union. Vol.12(s329). 414. https://doi.org/10.1017/S1743921317003064