Документ взят из кэша поисковой машины. Адрес оригинального документа : http://www.naic.edu/~ptaylor/
Дата изменения: Mon Dec 21 18:42:45 2015
Дата индексирования: Sat Apr 9 22:35:27 2016
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Поисковые слова: elliptical galaxy
Patrick A. Taylor, Group Lead for Planetary Radar, Staff Scientist at the National Astronomy and Ionosphere Center's William E. Gordon Telescope at Arecibo Observatory

Contact Information

Arecibo Observatory
HC 3 Box 53995
Arecibo, PR 00612

Email: ptaylor 'aT naic.edu
Phone: 787-878-2612 x358
Fax: 787-878-1861

Curriculum Vitae - Full, Short, List of Publications

Publications

Selected Abstracts


Past and Current Research

I was lead author on one of the companion papers published in Science that determined the observed change in spin rate of near-Earth asteroid 54509 YORP (formerly 2000 PH5) is the best evidence for a direct detection of the YORP effect (obviously, the asteroid was renamed following the detection). I used one-dimensional radar echo spectra and high resolution, two-dimensional, delay-Doppler images of the asteroid from the Arecibo telescope S-band (12.6 cm) radar combined with X-band (3.5 cm) radar spectra and images from the Goldstone telescope and optical lightcurves provided by astronomers around the world to determine the spin pole location and reconstruct a three-dimensional shape model of the asteroid. While lightcurve observers could show there was an observable change in the sidereal spin rate of the asteroid (using the spin pole location I provided), the shape model was necessary to show that the predicted change in spin rate due to the YORP effect on that specific shape was in agreement with observation. A brief summary is given on my advisor Jean-Luc Margot's webpage.


I also discovered a satellite orbiting near-Earth asteroid 2004 DC (above) using the Arecibo radar. The satellite was subsequently observed in radar images (below) from the Goldstone telescope on the following days including what appears to be a mutual event where the secondary moves behind the primary into its radar "shadow" and then reappears. More information can be found in the CBET Telegram of the discovery and on the planning page for the observations. It is interesting to note that 2004 DC has an eccentric mutual orbit and the secondary is asynchronous!



I am currently working on a shape model for 2004 DC, which shows some similarity to that of 1999 KW4.

I am also interested in celestial mechanics. Right now, I am looking into the dynamical interaction of the components of small Solar System binaries, especially their tidal interactions where I try to use their current orbital configuration and age estimate to describe their internal structure and mechanical properties. One outstanding question is "why do some binaries have eccentric mutual orbits?" as one might expect them to damp out from tides into circular, synchronous orbits. In fact, a handful of near-Earth binaries are asynchronous and eccentric (like 2004 DC) while the rest are circularized and synchronous (like 1999 KW4, essentially). Are they simply young? Have they been recently excited by a close planetary encounter? Is something more exotic going on?

With the validation of the YORP effect and its acceptance as a major binary formation mechanism, how YORP affects the dynamics of the system must also be considered. If binaries tend to be KW4-like where the equator of the primary is essentially weightless, one must also consider the tidal ability of the secondary to drag loose material across the surface of the primary or even lift material off the surface of the primary. This sort of dragging or lifting could dissipate energy and redistribute angular momentum at rates rivaling (exceeding?) that of tides!