Near-Infrared Spectroscopy of Near-Earth Asteroids: 3122 Florence, (357439) 2004 BL86, 1036 Ganymed, and 4055 Magellan

Abstract

The near-infrared spectra of four near-Earth asteroids, 3122 Florence, (357439) 2004 BL86, 1036 Ganymed, and 4055 Magellan, were analyzed for traces of surface water. NEAs are widely thought to be the source of water and organics delivered to early Earth. Additionally, some NEAs are considered potentially hazardous objects (PHOs), and they could make threateningly close approaches to our planet. The Infrared Telescope Facility (IRTF), located at Mauna Kea, Hawaii, was used to measure long wavelength cross-dispersed (LXD) spectra of these four asteroids with SpeX mode. The measured spectra wavelength ranged from 1.67-4.2 μm, which includes the 3-μm feature attributed to water/hydroxyl. The 3μm spectral feature was found on Florence, but not on 2004 BL86; meanwhile, the Ganymed and Magellan results were inconclusive. Discovering water on a celestial body such as Florence, an S-type asteroid, is highly unusual and warrants further study.