Ground‐Based Near‐Infrared Imaging of the HD 141569 Circumstellar Disk

Abstract

We present the first ground-based near-infrared image of the circumstellar disk around the post-Herbig Ae/Be star HD 141569A initially detected with the Hubble Space Telescope (HST). Observations were carried out in the near-IR (2.2 μm) at the Palomar 200 inch telescope using the adaptive optics system PALAO. The main large-scale asymmetric features of the disk are detected on our ground-based data. In addition, we measured that the surface brightness of the disk is slightly different than that derived by HST observations (at 1.1 and 1. 6 μm). We interpret this possible color effect in terms of dust properties and derive a minimal grain size of 0.6 ± 0.2 μm for compact grains and a power-law index for the grain size distribution smaller than -3. Basic dynamical considerations are consistent with the presence of a remnant amount of gas in the disk.