Astronomical studies of solar system bodies 2060 Chiron and 1 Ceres

[摘要] In this thesis two separate projects are investigated, a stellar occultation by 2060 Chiron and rotationally resolved spectra of 1 Ceres. On 29 November 2011 UT, 2060 Chiron occulted a 14-mag star; data were successfully obtained at the 3-m IRTF on Mauna Kea and 2-m Faulkes North Telescope at Haleakala. The IRTF lightcurve shows a solid-body detection of Chiron;;s nucleus with a chord lasting 16.04 seconds, corresponding to a chord length of 158±14 km. Symmetric, dual extinction features in the Faulkes light curve indicate the presence of optically thick material roughly 300 km from the body midpoint. The duration of the features indicates a ~ 3 km feature separated by 10-14 km from a second - 7 km feature. The symmetry, optical thickness, and narrow size of these features allows for the intriguing possibility of a near-circular arc or shell of material. Rotationally resolved spectra of Ceres in the 0.43-0.85 micron range were observed using the DeVeny spectrograph on the Perkins 72-inch telescope at Lowell Observatory. Spectral differences as a function of phase were investigated. It is concluded that Ceres;; surface is uniform at the 1% level at visible wavelengths. Additionally, the 0.6 and 0.67 pm features reported by Vilas and McFadden [1992] and Fornasier et al. [1999] are not seen at any phase at the 1% level.

[发布机构] Massachusetts Institute of Technology