Continuum or bimodality in methanol absorption

Determine whether the observed trend in methanol absorption among organic-rich Kuiper Belt Objects is continuous with optical color or instead represents a bimodal distribution corresponding to distinct subclasses.

Background

The paper reports that the linear spectral model fails to reproduce the methanol absorption behavior of the organic-rich sample. The apparent trend is driven primarily by the reddest organics-type objects, while the remaining organic-rich objects may exhibit an opposite trend, suggesting either a continuous dependence on optical color or a bimodal structure.

Resolving this issue bears directly on whether the proposed Cliff-1 and Cliff-2 subclasses represent genuinely distinct populations or merely the endpoints of a continuous compositional sequence. The authors state that additional spectra are required to distinguish these possibilities.