Near-infrared multiwavelength imaging polarimetry of the low-mass proto-stellar object HL Tauri
Max-Planck-Institut für Radioastronomie, Auf dem Hügel 69, 53121 Bonn, Germany e-mail: email@example.com
2 Subaru Telescope, National Astronomical Observatory of Japan, 650 North A'ohoku place, Hilo, HI 96720, USA
Accepted: 15 October 2008
We present the -band high-resolution polarimetric images of the low-mass proto-stellar object HL Tau using the adaptive optics-equipped CIAO instrument on the Subaru telescope. Our polarization images show a butterfly-shaped polarization disk with an extension. In the nebula, where polarization vectors are centro-symmetrically aligned, the polarization is as high as , , and . On the other hand, low polarizations of % in the J, H, and K bands and a low color excess ratio of compared to the standard cloud value of 1.75 are detected towards the central star. We estimated the upper limit of the grain sizes to be 0.4 μm in the nebula and 0.7 μm in the line of sight towards the central star. Our high-resolution polarimetric data, which spatially resolves the polarization disk, provides us with important information about grain growth in the region close to the central star.
Key words: polarization / ISM: dust, extinction
© ESO, 2008