In late 1987, as Chiron approached perihelion, it brightened more than was expected for an atmosphereless body ( Bowell et al., 1988). It was assumed that this was due to cometary activity but no direct evidence of a coma was seen. Variations of brightness ranging from 1.9 to 28.8 % were interpreted as a variable rotational amplitude by Bus et al. (1988). This led Meech and Belton (1990) to propose that Chiron has a bound dust atmosphere where micron-sized dust particles would be entrained in escaping gases and lifted off the surface. Most of the dust would not attain escape velocities and would be confined within a region with a radius of about 5000 km, where it would interact with the impinging solar wind.
Meech et al. (1994) obtained 44 broadband green PC images (the F555W filter) on February 22-23 and March 8, 1993, when Chiron was near its minimum geocentric distance. Deconvolved images showed azimuthal structure within 1.3 arcseconds of the nucleus. The brightness and azimuthal locations of irregularities vary with time and are not azimuthally symmetric and may be related to shell structure in the coma. Based on the predictions of Meech and Belton, some of the characteristics derived from these observations were not expected. The HST improved resolution capabilities will be utilized to further characterize the nature of this small body.