Dr. Angela Cotera Proud to be star-struck, physicist Angela Cotera is keen to better understand the chain of events that precede the birth of a star and, at least in some cases, accompanying planets. To this end, she is a team member of NSTARS, a project being pursued on the Spitzer Space Telescope to investigate all stars within 70 light-years of the Sun to see what fraction have protoplanetary disks. This is a straightforward approach to answering a very fundamental question: how often does the formation of stars also produce solar systems?
In addition to her disk studies, Angela also studies such “extreme” stellar environments as large HII regions and the galactic center. The former are mammoth stellar nurseries (think of the Great Nebula in the constellation of Orion), where enormously hot, giant stars are heating the surrounding gas to high temperature. The latter is the inner core of the Milky Way, where the density of stars is millions of times higher than in the neighborhood of our Sun. By investigating these tough galactic neighborhoods, Angela hopes to gain a better understanding of how the formation of planets is governed by nurture as well as nature.
Projects
Coronagraphic Polarimetry with NICMOS
HST-GO-10852.05A
A Paschen-Alpha Study of Massive Stars and the ISM in the Galactic Center
HST-GO-11120.03
We have completed the first large-scale survey of the Galactic center in P-alpha emission using narrow band imaging with the NIC3 camera. As part of the Phase ll process, funding was originally requested to provide for advanced data processing to ensure the quality inherent in the acquired data was achieved. During the review process, the FRC cut funding for this enhanced data reduction effort, citing the request as unnecessary due to advances in the OPUS pipeline processing. Funding was provided, however, to conduct a test evaluation of the pipeline processing to confirm that the processing was adequate. We have found that the OPUS pipeline processing does not meet the program goals. Our enhanced data processing methodology provides for an overall improvement of ~20% in the image noise in both the F187N and F190N filters, providing for an minimum of a 23% improvement in the P-alpha emission image noise. In addition, our methodology enables additional improvements at smaller spatial scales from flat field, pixel masks, dither combining and dark current considerations.
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