UBVRI Photometry of Mecury's Integral Phase Curve
2007 (English)Conference paper (Other (popular scientific, debate etc.))
We present results from a photometric survey of Mecury's survey of Mecury's integral phase curve in the Johnson UBVRI system, obtained with the 0.9-m Westerlund Telescope in Uppsala, Sweden. CCD observations of the integrated disk have been obtained for the phase angle range 22-152 degrees. This is the first integral phase curve survey covering the extended visible spectrum of Mecury. We have derived absolute magnitudes and color indices from which Bond albedo, geometric albedo and phase integral have been determined for all bands.
We have fitted the data in each band with the Mallama et a. (2002) V-band phase curve which is based on a wider range of more densely sampled phase angles. A magnitude-scaled Mallama phase curve provided adequate fits for each band within the photometric error budget. This implies no evidence of phase reddening in any color, which is in contrast to the Moon. The phase reddening for the Moon was determined by Lane and Irvine (1973) to 0.001 mag/degree between the wavelengths 445 nm and 550 nm.
These data will be modeled to derive light scattering properties of the regolith. Of particular interest is the prediction of a disk-averaged normal albedo at 1064 nm with implications for the returned signal strength of the BepiColombo laser altimeter BELA (Gunderson et al, 2006).
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IdentifiersURN: urn:nbn:se:uu:diva-13803OAI: oai:DiVA.org:uu-13803DiVA: diva2:41573