Munetake Momose

Direct Imaging of Fine Structures in Giant Planet Forming Regions of the Protoplanetary Disk around AB Aurigae

We report high-resolution 1.6 μm polarized intensity (PI) images of the circumstellar disk around the Herbig Ae star AB Aur at a radial distance of 22 AU (015) up to 554 AU (385), which have been obtained by the high-contrast instrument HiCIAO with the dual-beam polarimetry. We revealed complicated and asymmetrical structures in the inner part (140 AU) of the disk while confirming the previously reported outer (r 200 AU) spiral structure. We have imaged a double ring structure at ~40 and ~100 AU and a ring-like gap between the two. We found a significant discrepancy of inclination angles between two rings, which may indicate that the disk of AB Aur is warped. Furthermore, we found seven dips (the typical size is ~45 AU or less) within two rings, as well as three prominent PI peaks at ~40 AU. The observed structures, including a bumpy double ring, a ring-like gap, and a warped disk in the innermost regions, provide essential information for understanding the formation mechanism of recently detected wide-orbit (r > 20 AU) planets.

Subaru imaging of asymmetric features in a transitional disk in upper Scorpius

We report high-resolution (0.07 arcsec) near-infrared polarized intensity images of the circumstellar disk around the star 2MASS J16042165-2130284 obtained with HiCIAO mounted on the Subaru 8.2 m telescope. We present our

SINTERING-INDUCED DUST RING FORMATION IN PROTOPLANETARY DISKS: APPLICATION TO THE HL TAU DISK

H

Local Enhancement of the Surface Density in the Protoplanetary Ring Surrounding HD 142527

-band data, which clearly exhibits a resolved, face-on disk with a large inner hole for the first time at infrared wavelengths. We detect the centrosymmetric polarization pattern in the circumstellar material as has been observed in other disks. Elliptical fitting gives the semimajor axis, semiminor axis, and position angle (P.A.) of the disk as 63 AU, 62 AU, and -14

A NEAR-INFRARED STUDY OF THE NGC 7538 STAR-FORMING REGION

^{\circ}

FIRST DETECTION OF SUBMILLIMETER POLARIZATION FROM T TAURI STARS

, respectively. The disk is asymmetric, with one dip located at P.A.s of

A submillimetre imaging polarimeter at the James Clerk Maxwell Telescope

\sim85^{\circ}

MILLIMETER-WAVE POLARIZATION OF PROTOPLANETARY DISKS DUE TO DUST SCATTERING

. Our observed disk size agrees well with a previous study of dust and CO emission at submillimeter wavelength with Submillimeter Array. Hence, the near-infrared light is interpreted as scattered light reflected from the inner edge of the disk. Our observations also detect an elongated arc (50 AU) extending over the disk inner hole. It emanates at the inner edge of the western side of the disk, extending inward first, then curving to the northeast. We discuss the possibility that the inner hole, the dip, and the arc that we have observed may be related to the existence of unseen bodies within the disk.

SUBMILLIMETER IMAGING POLARIMETRY OF THE NGC 7538 REGION

The latest observation of HL Tau by ALMA revealed spectacular concentric dust rings in its circumstellar disk. We attempt to explain the multiple ring structure as a consequence of aggregate sintering. Sintering is known to reduce the sticking efficiency of dust aggregates and occurs at temperatures slightly below the sublimation point of their constituent material. We here present a dust growth model incorporating sintering and use it to simulate global dust evolution due to sintering, coagulation, fragmentation, and radial inward drift in a modeled HL Tau disk. We show that aggregates consisting of multiple species of volatile ices experience sintering, collisionally disrupt, and pile up at multiple locations slightly outside the snow lines of the volatiles. At wavelengths of 0.87--1.3 mm, these sintering zones appear as bright, optically thick rings with a spectral slope of

MASS ESTIMATES OF A GIANT PLANET IN A PROTOPLANETARY DISK FROM THE GAP STRUCTURES

\approx 2