Thermal Infrared and Optical Photometry of Asteroidal Comet C/2002 CE$_{10}$

摘要

C/2002 CE$_{10}$ is an object in a retrograde elliptical orbit with Tisserandparameter $-0.853$ indicating a likely origin in the Oort Cloud. It appears tobe a rather inactive comet since no coma and only a very weak tail was detectedduring the past perihelion passage. We present multi-color optical photometry,lightcurve and thermal mid-IR observations of the asteroidal comet.\textcolor{blue}{ With the photometric analysis in $BVRI$, the surface color isfound to be redder than asteroids, corresponding to cometary nuclei andTNOs/Centaurs. The time-resolved differential photometry supports a rotationperiod of 8.19$\pm$0.05 h. The effective diameter and the geometric albedo are17.9$\pm$0.9 km and 0.03$\pm$0.01, respectively, indicating a very darkreflectance of the surface. The dark and redder surface color of C/2002CE$_{10}$ may be attribute to devolatilized material by surface aging sufferedfrom the irradiation by cosmic rays or from impact by dust particles in theOort Cloud. Alternatively, C/2002 CE$_{10}$ was formed of very dark refractorymaterial originally like a rocky planetesimal. In both cases, this object lacksices (on the surface at least). The dynamical and known physicalcharacteristics of C/2002 CE$_{10}$ are best compatible with those of theDamocloids population in the Solar System, that appear to be exhaust cometarynucleus in Halley-type orbits. The study of physical properties of rocky Oortcloud objects may give us a key for the formation of the Oort cloud and thesolar system.