【日時】11月2日(水)　10:30～12:00
【場所】国立天文台・三鷹　中央棟（北）1階 講義室
【発表者（敬称略）】Kwon Jungmi（総研大 D2・三鷹、指導教員 : 田村 元秀）
【タイトル】Linear and circular imaging polarimetry of the Chamaeleon infrared nebula
ABSTRACT ( Gledhill et al. 1996 )
We present linear and circular imaging polarimetry observations of the Chamaeleon infrared nebula, a bipolar reflection nebula in the Chamaeleon I dark cloud, at near-infrared (JHKn) wavelengths.
These are amongst the first imaging circular polarimetry results for a star-forming region. The detection of both high degrees of linear polarization and a significant degree of circular polarization in the extended nebulosity allows us to comment on the scattering geometry and the range of particle sizes present.
We develop a model incorporating a polarized source which can successfully account for the observed linear and circular polarimetry and for the asymmetries in nebular brightness (the ‘bright rim’ structures) seen in this and other objects (e.g., NGC 2261/R Mon). In order to do so, the model requires a non-axisymmetric illumination of the nebula, and we discuss possible origins for this asymmetry, including disruption of a circumstellar disc by binary protostars.