Imaging the circumstellar environment of the young T Tauri star SU Aurigae

¹ Institut für Astrophysik, Georg-August-Universität, Friedrich-Hund-Platz 1, 37077 Göttingen, Germany
e-mail: Jeffers@astro.physik.uni-goettingen.de
² Leiden Observatory, PO Box 9513, 2300 RA Leiden, The Netherlands
³ Sterrenkundig Instituut Anton Pannekoek, Universiteit van Amsterdam, Postbus 94249, 1090 GE Amsterdam, The Netherlands
⁴ Departamento de Física y Astronomia, Universidad de Valparaiso, 5030 Casilla, Valparaiso, Chile

Received: 7 August 2012
Accepted: 21 October 2013

Abstract

The circumstellar environments of classical T Tauri stars are challenging to directly image because of their high star-to-disk contrast ratio. One method to overcome this is by using imaging polarimetry where scattered and consequently polarised starlight from the star’s circumstellar disk can be separated from the unpolarised light of the central star. We present images of the circumstellar environment of SU Aur, a classical T Tauri star at the transition of T Tauri to Herbig stars. The images directly show that the disk extends out to 500 AU with an inclination angle of ~50°. Using interpretive models, we derived very small grains in the surface layers of its disk, with a very steep size- and surface-density distribution. Additionally, we resolved a large and extended nebulosity in our images that is most likely a remnant of the prenatal molecular cloud. The position angle of the disk, determined directly from our images, rules out a polar outflow or jet as the cause of this large-scale nebulosity.