Imagers view comet Hale-Bopp's sodium tail



Ultraviolet, visible, and spectrographic imagers (UVISI) aboard the MSX satellite observed the sodium tail of comet Hale-Bopp last year and successfully modeled it using a point source at the nucleus, or inner coma. UVISI also observed the comet's dust and ion tails (Figure 1).

The derived abundance of sodium is much lower than cosmic abundances, suggesting detection of only a fraction of the sodium in the comet [Kupperman et al., 1998; Cremonese et al., 1997]. The additional sodium may remain in the nucleus, in molecular species, or in the dust grains.