106 research outputs found
Sub-Arcsecond Near-Infrared Images of Massive Star Formation Region NGC 6334 V
We present high spatial resolution (0\farcs3) polarimetric images in the
and bands and direct images in the and bands of the NGC 6334
V infrared nebulae. The images show complex structures including the
multi-shells and various knots in the nebulae. The appearances and colors of
the eastern and western nebulae differ considerably. Our polarization images
also show differences between the illuminating sources of the nebulae: the
eastern nebula is illuminated by a deeply embedded mid-infrared source, KDJ 4,
and the western nebula by our newly detected near-infrared source, WN-A1. The
degree of polarization of the nebulae is very large, up to 70% at and 60%
at , which is consistent with a single scattering of near-infrared radiation
from each source at the walls of the mass outflows
SUBARU Near-Infrared Multi-Color Images of Class II Young Stellar Object, RNO91
We conducted sub-arcsecond near-infrared imaging observations of RNO91 with
CIAO mounted on the SUBARU 8.2 m telescope. We present our JHK band data along
with optical images, which when considered together reveal a complex
circumstellar structure. We examined the colors of associated nebula and
compared the geometry of the outflow/disk system suggested by our data with
that already proposed on the basis of previous studies. Our K-band image shows
bright circumstellar nebulosity detected within 2"(300AU) around the central
source while it is less conspicuous at shorter wavelengths such as J and
optical. P.A. and size of this red color nebulosity in our H-K color image
agree with those of the previously detected polarization disk. These data
agreement indicate that this bright circumstellar nebulosity region which
follows the reddening law might be attributed to a disk-like structure. At J
and optical wavelengths, several blue knot-like structures are detected around
and beyond the bright circumstellar nebulosity. We suggest that these knotty
reflection nebulae may represent disintegrating fragments of an infalling
envelope. The three-color composite image has an appearance of arc-shaped
nebulosity extending to the north and to the east through the central source.
On the other end of this arc-shaped structure, the nebula appears to become
more extended (2."3 long) to the southwest. We interpret these structures as
roots of bipolar cavities opening to the northeast and southwest. The complex
distribution of reflection nebulosity seen around RNO91 appears to confirm the
interpretation of this source as an object dispersing its molecular envelope
while transitioning from protostar to T Tauri star.Comment: 18 pages, 6 figures, Accepted by Publications of the Astronomical
Society of Japa
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 yrs and the total mass of the binary is ~1.73 solar mass. 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 southwest part but a barely detectable
northeast portion. The brightness ratio is ~57. Its inner radius and
inclination are about 520 AU and 42, 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 a part of the disk, created by the accretion from the outer region
of the disk or encounters with other stellar systems.Comment: 16 pages, 6 figures; accepted for publication in A
The shadow knows: using shadows to investigate the structure of the pretransitional disk of HD 100453
We present GPI polarized intensity imagery of HD 100453 in Y-, J-, and K1
bands which reveals an inner gap ( au), an outer disk ( au) with
two prominent spiral arms, and two azimuthally-localized dark features also
present in SPHERE total intensity images (Wagner 2015). SED fitting further
suggests the radial gap extends to au. The narrow, wedge-like shape of the
dark features appears similar to predictions of shadows cast by a inner disk
which is misaligned with respect to the outer disk. Using the Monte Carlo
radiative transfer code HOCHUNCK3D (Whitney 2013), we construct a model of the
disk which allows us to determine its physical properties in more detail. From
the angular separation of the features we measure the difference in inclination
between the disks 45, and their major axes, PA = 140 east
of north for the outer disk and 100for the inner disk. We find an
outer disk inclination of from face-on in broad agreement
with the Wagner 2015 measurement of 34. SPHERE data in J- and H-bands
indicate a reddish disk which points to HD 100453 evolving into a young debris
disk
Differences in the gas and dust distribution in the transitional disk of a sun-like young star, PDS 70
We present ALMA 0.87 mm continuum, HCO+ J=4--3 emission line, and CO J=3--2
emission line data of the disk of material around the young, Sun-like star PDS
70. These data reveal the existence of a possible two component transitional
disk system with a radial dust gap of 0."2 +/- 0."05, an azimuthal gap in the
HCO+ J=4--3 moment zero map, as well as two bridge-like features in the gas
data. Interestingly these features in the gas disk have no analogue in the dust
disk making them of particular interest. We modeled the dust disk using the
Monte Carlo radiative transfer code HOCHUNK3D (Whitney et al. 2013) using a two
disk components. We find that there is a radial gap that extends from 15-60 au
in all grain sizes which differs from previous work
Subaru near infrared coronagraphic images of T Tauri
High angular resolution near-infrared (JHK) adaptive optics images of T Tau were obtained with the infrared camera Coronagraphic Imager with Adaptive Optics (CIAO) mounted on the 8.2m Subaru Telescope in 2002 and 2004. The images resolve a complex circumstellar structure around a multiple system. We resolved T Tau Sa and Sb as well as T Tau N and S. The estimated orbit of T Tau Sb indicates that it is probably bound to T Tau Sa. The K band flux of T Tau S decreased by ˜ 1.7 Jy in 2002 November compared with that in 2001 mainly because T Tau Sa became fainter. The arc-like ridge detected in our near-infrared images is consistent with what is seen at visible wavelengths, supporting the interpretation in previous studies that the arc is part of the cavity wall seen relatively pole-on. Halo emission is detected out to ˜2\u27\u27from T Tau N. This may be light scattered off the common envelope surrounding the T Tauri multiple system
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