Tomoyuki Kudo

Near-Infrared Images of Protoplanetary Disk Surrounding HD 142527*

We discovered a unique morphology in a disk around the Herbig Ae star HD 142527 by near-infrared (H and K bands) adaptive optics imaging observations. The almost face-on disk consists of two bright arcs facing one another along the east-west direction (banana-split structure) and one spiral arm extending to the north from the western arc. The eastern arc is located at ~100-400 AU in radius from the star, and the western one is detected at ~150-490 AU. The stellar position is displaced from the center of the disk by about 20 AU to the north, and also from the center of the inner hole. The two arcs show an asymmetry in their size and brightness; the larger western arc is brighter than the east one by about 2 mag. The morphology of the disk, consisting of a banana-split structure and a spiral arm, most likely suggests the presence of an unseen eccentric binary and a recent stellar encounter.

Near-Infrared Coronagraphic Observations of the T Tauri Binary System UY Aur*

We present a near-infrared image of UY Aur, a 0.9 separated binary system, using the Coronagraphic Imager with Adaptive Optics on the Subaru Telescope. Thanks to adaptive optics, the spatial resolution of our image was ~0.1 in the full width at half-maximum of the point-spread function, the highest achieved. By comparison with previous measurements, we estimated that the orbital period is ~1640 ± 90 yr and the total mass of the binary is ~1.73 ± 0.29 M⊙. The observed H-band magnitude of the secondary varies by as much as 1.3 mag within a decade, while that of the primary is rather stable. This inconstancy may arise from photospheric variability caused by an uneven accretion rate or from the rotation of the secondary. We detected a half-ring-shaped circumbinary disk around the binary with a bright southwestern part but a barely detectable northeastern portion. The brightness ratio is 57 ± 5. Its inner radius and inclination are about 520 AU and 42° ± 3°, respectively. The disk is not uniform but has remarkable features, including a clumpy structure along the disk, circumstellar material inside the inner cavity, and an extended armlike structure. The circumstellar material inside the cavity probably corresponds to a clump or material accreting from the disk onto the binary. The armlike structure is part of the disk, created by accretion from the outer region of the disk or encounters with other stellar systems.

Subarcsecond Near-Infrared Images of Massive Star Formation Region NGC 6334 V

We present high spatial resolution (0

Discovery of a Scattering Disk around the Low-Mass T Tauri Star FN Tauri

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SUBARU near-infrared multi-color images of Class II Young Stellar Object, RNO91

3) polarimetric images in the

Thermal-infrared adaptive optics imaging- and spectro-polarimetry with the infrared camera and spectrograph (IRCS) for the Subaru Telescope

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A coronagraphic search for brown dwarfs and planets around nearby stars

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Near-Infrared Spectroscopy of Faint Companions around Young Stellar Objects Associated with the Taurus Molecular Cloud

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Subaru near infrared coronagraphic images of T Tauri

bands and direct images in the

Near-Infrared Coronagraphic Observations of a Classical T Tauri Star, DO Taurus

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