Many stars are surrounded by gaseous and dusty disk. While the gaseous disk parts often produce measurable amounts of molecular emission, e.g., in CO, with emission bands in the near-infrared spectral range, the dust parts cause on the one hand strong continuum emission noticeable via an infrared excess, but also spectral features corresponding to vibrational transitions in small dust particles.

Our investigations deal with both the molecular and the dusty parts. For the molecular disk regions, we studied so far mainly the CO band emission in order to constrain the disk parameters such as density and temperature, but also the kinematics (Keplerian rotation versus outflow).

We study the disks of evolved massive stars using both observations in different wavelength regions, but we also developed our theoretical models and numerical codes. Below is a selection of our results on

Molecular disks

A description of the code developed to model CO band emission from disks and winds is described in the following publication:

CO band emission from MWC 349 - Kraus, Krügel, Thum, & Geballe, 2000, A&A, 362, 158

Applications to the molecular disks of evolved massive stars can be found in a variety of publications, e.g.,

CPD-52 9243 - Cidale, Borges Fernandes, Andruchow, Arias, Kraus, Chesneau, Kanaan, Curé, de Wit, & Muratore, 2012, A&A, in press

GG Car - Kraus, Oksala, Nickeler, Muratore, Borges Fernandes, Aret, Cidale, de Wit, A&A, submitted

The CO bands are also found to be ideal age indicators

The 13Carbon footprint of B[e] supergiants - Kraus, 2009, A&A, 494, 253 & Liermann, Kraus, Schnurr, & Borges Fernandes, 2010, MNRAS, 408, L6

Dusty disks

Detailed descriptions of the radiative transfer codes developed and used to study the structure of the dusty disks is described in the following two publications:

SEDs of flared dust disks - Kraus, 2003, in Open Issues in Local Star Formation, p. 279

The dusty disk of CD-42 11721 - Borges Fernandes, Kraus, Lorenz Martins, & de Araújo, 2007, MNRAS, 377, 1343