Detection of Water and/or Hydroxyl on Asteroid (16) Psyche

Abstract

In order to search for evidence of hydration on M-type asteroid (16) Psyche, we observed this object in the 3 micron spectral region using the long-wavelength cross-dispersed (LXD: 1.9-4.2 micron) mode of the SpeX spectrograph/imager at the NASA Infrared Telescope Facility (IRTF). Our observations show that Psyche exhibits a 3 micron absorption feature, attributed to water or hydroxyl. The 3 micron absorption feature is consistent with the hydration features found on the surfaces of water-rich asteroids, attributed to OH- and/or H2O-bearing phases (phyllosilicates). The detection of a 3 micron hydration absorption band on Psyche suggests that this asteroid may not be metallic core, or it could be a metallic core that has been impacted by carbonaceous material over the past 4.5 Gyr. Our results also indicate rotational spectral variations, which we suggest reflect heterogeneity in the metal/silicate ratio on the surface of Psyche.

13 pages, 9 figures in Astronomical Journal, 2016

References in corpus (2)

• The Composition of M-type asteroids II: Synthesis of spectroscopic and radar observations
• Phase Angle Effects on 3-micron Absorption Band on Ceres: Implications for Dawn Mission

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• The Main Belt Comets and Ice in the Solar System
• Asteroid 16 Psyche: Shape, Features, and Global Map
• The Heterogeneous Surface of Asteroid (16) Psyche
• Constraining the Regolith Composition of Asteroid (16) Psyche via Laboratory Near-infrared Spectroscopy
• Space Weathering of the 3-micron Phyllosilicate Feature induced by Pulsed Laser Irradiation
• Near-mid infrared spectroscopy of carbonaceous chondrites: Insights into spectral variation due to aqueous alteration and thermal metamorphism in asteroids