Rotationally-Resolved Surface Mineralogy of an Extinct Comet

Campins, Humberto; Emery, Joshua; Fernandez, Yanga; Licandro, Javier; Lisse, Carey
Bibliographical reference

Spitzer Proposal ID #30241

Advertised on:
5
2006
Number of authors
5
IAC number of authors
0
Citations
0
Refereed citations
0
Description
Object 944 Hidalgo is one of the asteroids most likely to be an extinct or dormant comet. Hidalgo's Tisserand invariant (T=2.07) suggests very strongly that this object originated either in the Kuiper belt or in the Oort cloud (Weissman et al. 2002). Our latest ground based results show significant rotational variability in the near-infrared spectrum of Hidalgo, but the ground based spectra are not sufficient to identify the nature of these surface variations. Spitzer observations of Hidalgo would be diagnostic of the surface mineralogy, as has been demonstrated for a number of asteroids (e.g., Emery et al. 2006). We propose to obtain 7.3 to 38 micron IRS spectra of 944 Hidalgo at 8 different rotational phases to characterize its surface composition and other properties such as thermal inertia.