2007AJ....133..526T

We present high signal precision optical reflectance spectra of the large Kuiper Belt objects 2005 FY9 and 2003 EL61. The spectrum of 2005 FY9 exhibits strong CH₄ ice bands. A comparison between the spectrum and a Hapke model indicates that the CH₄ bands are shifted 3.25±2.25 Å relative to pure CH₄ ice, suggesting the presence of another ice component on the surface of 2005 FY9, possibly N₂ ice, CO ice, or Ar. The spectrum of 2003 EL61 is remarkably featureless. There is a hint of an O₂ ice band at 5773 Å; however, this feature needs to be confirmed by future spectroscopic observations of 2003 EL61 with a higher continuum signal precision sufficient to detect a second, weaker O₂ ice band at 6275 Å.