David Wilner

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On 4 July 2005, many observatories around the world and in space observed the collision of Deep Impact with comet 9P/Tempel 1 or its aftermath. This was an unprecedented coordinated observational campaign. These data show that (i) there was new material after impact that was compositionally different from that seen before impact; (ii) the ratio of dust mass(More)
We report observations of 47 candidate protostars in two optically thick lines (H 2 CO 2 12 − 1 11 and CS 2 − 1) and one optically thin line (N 2 H + 1 − 0) using the IRAM 30-m, SEST 15-m, and Haystack 37-m radio telescopes. The sources were selected from the redness of their spectra (T bol < 200 K) and their near distance (d < 400 pc). Most of the sources(More)
After studying how line width depends on spatial scale in low-mass star-forming regions, we propose that " " dense cores ÏÏ & Benson represent an inner scale of a self-similar process that charac-(Myers 1983) terizes larger scale molecular clouds. In the process of coming to this conclusion, we deÐne four distinct types of line widthÈsize relation which(More)
We present observations of the young stars TW Hya and HD 100546 made with the Australia Telescope Compact Array at 89 GHz with ∼ 2 ′′ resolution and ∼ 3 mJy continuum sensitivity. Compact thermal dust continuum emission is detected from disks surrounding both stars. HD 100546 also shows hints of extended emission, presumably a residual protostellar(More)
We present the results of a high angular resolution (0. ′′ 3 ≈ 40 AU) Submillimeter Array survey of the 345 GHz (870 µm) thermal continuum emission from 9 of the brightest , and therefore most massive, circumstellar disks in the ∼1 Myr-old Ophiuchus star-forming region. Using two-dimensional radiative transfer calculations, we simultaneously fit the(More)
We review the properties of dust in protoplanetary disks around optically visible pre-main sequence stars obtained with a variety of observational techniques, from measurements of scattered light at visual and infrared wavelengths to mid-infrared spectroscopy and millimeter interferometry. A general result is that grains in disks are on average much larger(More)
We have used the Submillimeter Array (SMA) to make the first interferometric observations (beam size ∼ 1 ′′ , or ∼ 400 pc) of the 12 CO J=6-5 line and 435 µm (690 GHz) continuum emission toward the central region (half power field of view 17 ′′) of the nearby ultra-luminous infrared galaxy (ULIRG) Arp 220. These observations resolve the eastern and western(More)
The formation of gaseous giant planets is thought to occur in the first few million years after stellar birth. Models predict that the process produces a deep gap in the dust component (shallower in the gas). Infrared observations of the disk around the young star HD 142527 (at a distance of about 140 parsecs from Earth) found an inner disk about 10(More)