Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: Spectroscopic Survey of X-type Asteroids   We present reflected light spectral observations from 0.4 to 2.5 micron of 24
asteroids chosen from the population of asteroids initially classified as
Tholen X-type objects (Tholen, 1984). The X complex in the Tholen taxonomy
comprises the E, M and P classes which have very different inferred
mineralogies but which are spectrally similar to each other, with featureless
spectra in visible wavelengths. The data were obtained during several observing
runs in the 2004-2007 years at the NTT, TNG and IRTF telescopes. We find a
large variety of near-infrared spectral behaviors within the X class, and we
identify weak absorption bands in spectra of 11 asteroids. Our spectra,
together with albedos published by Tedesco et al. (2002), can be used to
suggest new Tholen classifications for these objects. In order to constrain the
possible composition of these asteroids, we perform a least-squares search
through the RELAB spectral database. Many of the best fits are consistent with
meteorite analogue materials suggested in the published literature. In fact, we
find that 7 of the new M-types can be fit with metallic iron (or pallasite)
materials, and that the low albedo C/P-type asteroids are best fitted with CM
meteorites, some of which have been subjected to heating episodes or laser
irradiation. Finally, we consider and analyse the sample of the X-type
asteroids we have when we combine the present observations with previously
published observations for a total of 72 bodies.

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The categories of this paper are: acc-phys
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The categories of this paper are: nucl-th
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The categories of this paper are: nlin
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The categories of this paper are: q-fin
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The categories of this paper are: atom-ph
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The categories of this paper are: hep-th
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The categories of this paper are: comp-gas
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The categories of this paper are: patt-sol
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The categories of this paper are: gr-qc
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The categories of this paper are: chem-ph
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The categories of this paper are: cs
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The categories of this paper are: hep-lat
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The categories of this paper are: alg-geom
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The categories of this paper are: cond-mat
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The categories of this paper are: q-bio
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The categories of this paper are: q-alg