Exposure of details of the formation of massive stars

• Applicant: Privatdozentin Dr. Katharina Schreyer
• Subject Area: Astrophysics and Astronomy
• Term: from 2008 to 2014
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 64018249

The birth process of massive stars is one of the unresolved mysteries of present research in star formation. Whether the dominant formation process for massive stars is disk accretion or coalescence is still an open question. The goal of this project is to resolve details of this process in terms of interferometric observations in the mm wavelength range. In a first step, we focus on already available data. Due to successful recent measurements with the VLA and the Plateau de Bure Interferometer, we detected different molecular species in the close vicinity of a 8-10M⊙-star (AFGL 490). A first look at the observational data implies on-going gas infall towards a disk-like structure with a radius of 1500 AU. Additionally newly discovered bow shocks along the line of the high-velocity outflow support evidence for on-going non-steady state mass accretion. In terms of modeling of the observational results, we would like to estimate physical properties of the detected gas (temperature and density profile, gas motion) as well as the mass accretion rate. Furthermore, we intend to study the nature of a dense 20 000 AU large bar-like gas structure perpendicularly located to the high-velocity outflow and centered at the massive star. We want to answer the question which role this gas bar (or disk ?) plays during the star formation. In a second step of our project, we would like to extend our search for comparable structures around more luminous, very young stars to find out whether these structures are common features during massive star formation or a special configuration in case of our selected target.

• DFG Programme: Research Grants