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Towson University


Khaldoun's speech

Physics, Astronomy, & Geosciences






My research currently focuses on high-resolution images of asteroids, primarily with the Hubble Space Telescope. Our "snapshot" survey of asteroids recently confirmed a companion to 87 Sylvia (cf. IAUC 7590), and the discovery of a companion to 107 Camilla (cf. IAUC 7599). Below are the discovery sequence, and the sequence of exposures from a follow-up visit almost four weeks later. Note that the although the companion doesn't appear clearly in the follow-up, it could easily be in the "vignetted region" of HST's WFPC-2 instrument, or in conjunction with the primary body.
Left column: A sequence of six HST WFPC-2 images of 107 Camilla made on March 1, 2001. Top to bottom, in temporal order (3 min. between exposures) the filters are F439W, F673N, F953N, F1042M, F791W, and F791W (saturated exposure). Background stars are observed in other parts of the chip, which move 43 pixels in two minutes.  Right column: The same images, linearly stretched between -10 DN and +20 DN, to show the companion. The companion is clearly seen to the right of the primary, in all but the near IR filters, which had inadequate exposure time to pick up the companion. The last exposure, which goes much deeper than the others (and so badly overexposes 107 Camilla) is stretched between -10 DN and +100 DN-- note the much higher signal-to-noise ratio for the companion. The companion maintains the same separation from the primary in all exposures, to better than half a pixel-- its not a background object or a known WFPC-2 artifact.