Ágnes Kóspál and Dániel Apai,
PARSAMIAN 21: HIGH-CONTRAST INFRARED MAPPING OF AN EDGE-ON FU ORI DISC

PARSAMIAN 21: HIGH-CONTRAST INFRARED MAPPING OF AN EDGE-ON FU ORI DISC

Ágnes Kóspál(1) and Dániel Apai(2,3)
(1) Konkoly Observatory of the Hungarian Academy of Sciences, P.O.Box 67, H-1525 Budapest, Hungary
(2) Steward Observatory, The University of Arizona, 933 N. Cherry Avenue, Tucson, AZ 85721, USA
(3) NASA Astobiology Institute

FU Ori-type objects (FUors) are low-mass pre-main sequence stars that have undergone outbursts in optical light of 4 mag or more. FUors are usually modelled by a flared accretion disc and an extended envelope. Outburst are thought to be caused by enhanced accretion from the disc to the star, triggered by an external event, probably the passing of a close companion.

Parsamian 21 is a unique object among FUors, as it is surrounded by an edge-on disc, which makes it an ideal case for studying disc/envelope structure. We present high-resolution, high-contrast imaging of Parsamian 21 obtained with VLT/NACO using the "differential polarimetric imaging" technique in the H band as well as direct images in the H, K$_S$ and L$^{\prime}$ bands. We could detect scattered light as close as 0.1 $^{\prime\prime}$ from the star, and measure the polarization structure of the innermost part of the system with unprecedented contrast and resolution. Using this dataset, we searched for close companions and tested the basic assumptions of FUor disc models.