Browsing by Author "Brown, RH"

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    Hydrogen concentrations on C-class asteroids derived from remote sensing
    (2003) Rivkin, AS; Davies, JK; Johnson, JR; Ellison, SL; Trilling, DE; Brown, RH; Lebofsky, LA
    We present spectroscopic observations of 16 asteroids from 1.9-3.6 mum collected from the United Kingdom Infrared Telescope (UKIRT) from 1996-2000. Of these 16 asteroids, I I show some evidence of a 3 mum hydrated mineral absorption feature greater than 2sigma at 2.9 mum. Using relations first recognized for carbonaceous chondrite powders by Miyamoto and Zolensky (1994) and Sato et al. (1997), we have determined the hydrogen to silicon ratio for these asteroids and calculated their equivalent water contents, assuming all the hydrogen was in water. The asteroids split into 2 groups, roughly defined as equivalent water contents greater than similar to7% (8 asteroids, all with 3 mum band depths greater than similar to20%) and less than similar to3% for the remaining 8 asteroids. This latter group includes some asteroids for which a weak but statistically significant 3 mum band of non-zero depth exists. The G-class asteroids in the survey have higher water contents, consistent with CM chondrites. This strengthens the connection between CM chondrites and G asteroids that was proposed by Burbine (1998). We find that the 0.7 mum and 3 mum band depths are correlated for the population of target objects.