Title

Water Ice And Organics On The Surface Of The Asteroid 24 Themis

Abstract

It has been suggested1-3 that Earthg's current supply of water was delivered by asteroids, some time after the collision that produced the Moon (which would have vaporized any of the pre-existing water). So far, no measurements of water ice on asteroids have been made, but its presence has been inferred from the comet-like activity of several small asteroids, including two members of the Themis dynamical family6. Here we report infrared spectra of the asteroid 24 Themis which show that ice and organic compounds are not only present on its surface but also prevalent. Infrared spectral differences between it and other asteroids make 24 Themis unique so far, and our identification of ice and organics agrees with independent results that rule out other compounds as possible sources of the observed spectral structure. The widespread presence of surface ice on 24 Themis is somewhat unexpected because of the relatively short lifetime of exposed ice at this distance (∼3.2 au) from the Sun. Nevertheless, there are several plausible sources, such as a subsurface reservoir that brings water to the surface through' impact gardeningg' and/or sublimation. © 2010 Macmillan Publishers Limited. All rights reserved.

Publication Date

4-29-2010

Publication Title

Nature

Volume

464

Issue

7293

Number of Pages

1320-1321

Document Type

Article

Personal Identifier

scopus

DOI Link

https://doi.org/10.1038/nature09029

Socpus ID

77951790141 (Scopus)

Source API URL

https://api.elsevier.com/content/abstract/scopus_id/77951790141

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