4015-WILSON-HARRINGTON, 2201-OLJATO, AND 3200-PHAETHON - SEARCH FOR CN EMISSION

There is evidence that 2201 Oljato and 3200 Phaethon may be inactive c ometary remnants. Comet P/Wilson-Harrington (1949 III) was discovered to be the same object as asteroid 4015 1979 VA. With this knowledge, w e made measurements of these near-Earth objects (NEOs) to search for t he CN (Delta nu=0) band emission at 3880 Angstrom-the most easily obse rved volatile species signature in comets. No CN emission feature was detected within 3-sigma for any of these NEOs. A Haser model was used to determine the production rate of CN (Q(CN)) correspending to 3-sigm a upper limits on the CN band flux. CN production rates were <4 x 10(1 2) mol . sec(-1) for 4015 Wilson-Harrington, <1 x 10(23) mol . sec(-1) for 2201 Oljato, and <1 x 10(23) mol . sec(-1) for 3200 Phaethon. The se production rates are lower (by as much as an order of magnitude) th an those observed in low production rate comets. We have lowered the u pper limits on eo for 2201 Oljato from its previous value by an order of magnitude. The active surface area required to produce the derived upper limit on Q(CN), <0.02% for 4015 Wilson-Harrington and <0.01% for 3200 Phaethon, is lower than those derived for most active comets. Ho wever, 2201 Oljato's active area, (0.4%, is within the lower end of th e active comet range. (C) 1996 Academic Press, Inc.