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Your search keyword '"Wu, Y.-L."' showing total 41 results
Start Over Author "Wu, Y.-L." Publisher iop publishing
41 results on '"Wu, Y.-L."'

37. DIFFRACTION-LIMITED VISIBLE LIGHT IMAGES OF ORION TRAPEZIUM CLUSTER WITH THE MAGELLAN ADAPTIVE SECONDARY ADAPTIVE OPTICS SYSTEM (MagAO).

Author

CLOSE, L. M., MALES, J. R., MORZINSKI, K., KOPON, D., FOLLETTE, K., RODIGAS, T. J., HINZ, P., WU, Y-L., PUGLISI, A., ESPOSITO, S., RICCARDI, A., PINNA, E., XOMPERO, M., BRIGUGLIO, R., UOMOTO, A., and HARE, T.

Subjects
STAR clusters, OPTICS, DIGITAL cameras, CCD cameras, IMAGE
Abstract

We utilized the new high-order (250-378 mode) Magellan Adaptive Optics system (MagAO) to obtain very high spatial resolution observations in "visible light" with MagAO's VisAO CCD camera. In the good-median seeing conditions of Magellan (0. ''5-0. ''7), we find MagAO delivers individual short exposure images as good as 19 mas optical resolution. Due to telescope vibrations, long exposure (60 s) r ' (0.63μm) images are slightly coarser at FWHM = 23-29 mas (Strehl -28%) with bright (R < 9 mag) guide stars. These are the highest resolution filled-aperture images published to date. Images of the young (-1Myr) Orion Trapezium θ1 Ori A, B, and C cluster members were obtained with VisAO. In particular, the 32 mas binary θ1 Ori C1C2 was easily resolved in noninterferometric images for the first time. The relative positions of the bright trapezium binary stars were measured with -0.6-5 mas accuracy. We are now sensitive to relative proper motions of just -0.2 mas yr-1 (-0.4 km s-1 at 414 pc)-this is a -2-10× improvement in orbital velocity accuracy compared to previous efforts. For the first time, we see clear motion of the barycenter of θ1 Ori B2B3 about θ1 Ori B1. All five members of the θ1 Ori B system appear likely to be a gravitationally bound "mini cluster," but we find that not all the orbits can be both circular and co-planar. The lowest mass member of the θ1 Ori B system (B4; mass -0.2M☉) has a very clearly detected motion (at 4.1 ± 1.3 km s-1; correlation = 99.9%) w.r.t. B1. Previous work has suggested that B4 and B3 are on long-term unstable orbits and will be ejected from this "mini cluster." However, our new "baseline" model of the θ1 Ori B system suggests a more hierarchical system than previously thought, and so the ejection of B4 may not occur for many orbits, and B3 may be stable against ejection in the long-term. This "ejection" process of the lowest mass member of a "mini cluster" could play a major role in the formation of low-mass stars and brown dwarfs. [ABSTRACT FROM AUTHOR]

Published
2013
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38. HIGH RESOLUTION Hα IMAGES OF THE BINARY LOW-MASS PROPLYD LV 1 WITH THE MAGELLAN AO SYSTEM.

Author

WU, Y.-L., CLOSE, L. M., MALES, J. R., FOLLETTE, K., MORZINSKI, K., KOPON, D., RODIGAS, T. J., HINZ, P., PUGLISI, A., ESPOSITO, S., PINNA, E., RICCARDI, A., XOMPERO, M., and BRIGUGLIO, R.

Subjects
*WAVELENGTHS, *OPTICS, *COMETS, *PROTOSTARS, *BROWN dwarf stars, *MAGNETOPAUSE
Abstract

We utilize the new Magellan adaptive optics system (MagAO) to image the binary proplyd LV 1 in the Orion Trapezium at Hα. This is among the first AO results in visible wavelengths. The Hα image clearly shows the ionization fronts, the interproplyd shell, and the cometary tails. Our astrometric measurements find no significant relative motion between components over ~18 yr, implying that LV 1 is a low-mass system.We also analyze Large Binocular Telescope AO observations, and find a point source which may be the embedded protostar's photosphere in the continuum. Converting the H magnitudes to mass, we show that the LV 1 binary may consist of one very-lowmass star with a likely brown dwarf secondary, or even plausibly a double brown dwarf. Finally, the magnetopause of the minor proplyd is estimated to have a radius of 110 AU, consistent with the location of the bow shock seen in Hα. [ABSTRACT FROM AUTHOR]

Published
2013
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