OPTICAL IMAGING POLARIMETRY OF THE LkCa 15 PROTOPLANETARY DISK WITH SPHERE ZIMPOL

Abstract

We present the first optical (590--890 nm) imaging polarimetry observations\nof the pre-transitional protoplanetary disk around the young solar analog LkCa\n15, addressing a number of open questions raised by previous studies. We detect\nthe previously unseen far side of the disk gap, confirm the highly eccentric\nscattered-light gap shape that was postulated from near-infrared imaging, at\nodds with the symmetric gap inferred from millimeter interferometry.\nFurthermore, we resolve the inner disk for the first time and trace it out to\n30 AU. This new source of scattered light may contribute to the near-infrared\ninterferometric signal attributed to the protoplanet candidate LkCa 15 b, which\nlies embedded in the outer regions of the inner disk. Finally, we present a new\nmodel for the system architecture of LkCa 15 that ties these new findings\ntogether. These observations were taken during science verification of SPHERE\nZIMPOL and demonstrate this facility's performance for faint guide stars under\nadverse observing conditions.\n