Maps of hco+ Emission in c/1995 o1 (Hale–Bopp) |
| |
Authors: | Womack M. Homich A. Festou M. C. Mangum J. Uhl W. T. Stern S. A. |
| |
Affiliation: | (1) Department of Physics and Astronomy, St. Cloud State University, St. Cloud, MN 56301-4498, USA;(2) Observatoire Midi Pyrénées, 14 avenue E. Belin, F-31400 Toulouse, France;(3) National Radio Astronomy Observatory, Tucson, AZ, USA;(4) Yale University, USA;(5) Southwest Research Institute, 1050 Walnut Street, No. 426, Boulder, CO 80302, USA |
| |
Abstract: | On-the-Fly maps of emission from the HCO+ J = 3-2 transition at 267.6 GHz were obtained of C/1995 O1 (Hale-Bopp) on 1997 Mar 15.6 UT using the NRAO 12-m telescope with high spatial resolution. Unlike the relatively symmetric and centralized maps of the neutral species CO, HCN and H2CO, the spatial extent of HCO+ emission is very diffuse with a complex structure characterized by at least two physically different regions. The bulk of the HCO+ emission peaks in intensity ∼175,000 km anti-sunward from the nuclear position. This peak emission does not fall directly along the anti-sunward direction, but is rotated by ∼10 degrees toward the east from the anti-sunward direction. A substantial void, or decrease, of HCO+ emission is observed within ∼ 55,000 km of the nucleus. The HCO+ emission in this void is roughly half the intensity of the emission observed 100,000 km away. This decrease of HCO+ emission near the nucleus may indicate that production or excitation of HCO+ is inhibited, or perhaps that HCO+ is easily destroyed in the inner coma, especially within ∼50,000 km of the nucleus. This void roughly coincides with the approximate location and size of the so-called “diamagnetic cavity” in the coma and may mark a significant transition region in the inner coma of Hale-Bopp This revised version was published online in July 2006 with corrections to the Cover Date. |
| |
Keywords: | Comet Hale– Bopp ions HCO+ |
本文献已被 SpringerLink 等数据库收录! |
|