K-band Radio Observations of Comet Hale-Bopp: Detections of Ammonia and (Possibly) Water     

Bird  M. K.  Janardhan  P.  Wilson  T. L.  Huchtmeier  W. K.  Gensheimer  P.  Lemme  C. 《Earth, Moon, and Planets》1997,78(1-3):21-28

K-band radio observations of comet Hale-Bopp (C/1995 O1) were conducted in March/April 1997 at the 100-m Telescope of the Max-Planck-Institut für Radioastronomie. Emission was firmly detected from the five lowest metastable (J = K)inversion transitions of ammonia. Assuming a thermal distribution for the metastable states of NH₃, we derive a rotational temperature of 104 ± 30 K and an ammonia production rate at perihelion of6.6 ± 1.3 × 10²⁸ s^-1.The updated ammonia-to-water abundance ratio is found to be of the order of 1.0%. We also report a marginal detection of the 6₁₆–5₂₃transition line of water at λ = 1.35 cm. This revised version was published online in July 2006 with corrections to the Cover Date.  相似文献