Mosaicked images and spectra of J=1→0 HCN and HCO+ emission from comet Hale-Bopp (1995 O1)

被引:30
作者
Wright, MCH
Depater, I
Forster, JR
Palmer, P
Snyder, LE
Veal, JM
Ahearn, MF
Woodney, LM
Jackson, WM
Kuan, YJ
Lovell, AJ
机构
[1] Univ Calif Berkeley, Dept Astron, Berkeley, CA 94720 USA
[2] Univ Chicago, Dept Astron & Astrophys, Chicago, IL 60637 USA
[3] Univ Illinois, Dept Astron, Urbana, IL 61801 USA
[4] Univ Maryland, Dept Astron, College Pk, MD 20742 USA
[5] Univ Calif Davis, Dept Chem, Davis, CA 95616 USA
[6] Natl Taiwan Normal Univ, Dept Earth Sci, Taipei, Taiwan
[7] Acad Sinica, Inst Astron & Astrophys, Taipei, Taiwan
[8] Five Coll Radio Astron Observ, Dept Astron, Amherst, MA USA
关键词
comets : individual (Hale-Bopp 1995 O1); techniques : interferometric;
D O I
10.1086/300650
中图分类号
P1 [天文学];
学科分类号
0704 ;
摘要
We used the BIMA array to map comet Hale-Bopp (1995 O1) in HCN and HCO+ emission at 89 GHz with 10 " angular resolution. The mosaicked images with seven pointing centers were combined with single-dish data to form completely sampled images of a region similar to 4' in diameter. The HCN image is roughly compatible with a Haser model in which most of the HCN comes from the nucleus. However, clear deviations from circular symmetry are present, and roughly 20% of the HCN does not appear to come from the nuclear source. Frequently, the HCN has an asymmetric, double-peaked profile. The double peak is expected from the Haser model, and the asymmetry observed on April 3 could come from an increased gas production toward the Sun and facing the observer. The abundance of HCN relative to H2O is similar to 0.3%. The HCO+, in contrast, is smooth, almost completely resolved in the interferometer observations, and offset toward the ion tail by about 1'. This behavior is compatible with expectations from a simple scaling of previous work.
引用
收藏
页码:3018 / 3028
页数:11
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