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

M. C.H. Wright*, I. De Pater, J. R. Forster, Patrick Palmer, Lewis E. Snyder, J. M. Veal, Michael F. A'Hearn, L. M. Woodney, William M. Jackson, Y. J. Kuan, A. J. Lovell

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

30 Citations (Scopus)


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 ∼ 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 ∼ 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.

Original languageEnglish
Pages (from-to)3018-3028
Number of pages11
JournalAstronomical Journal
Issue number6
Publication statusPublished - 1998 Dec


  • Comets: individual (Hale-Bopp 1995 O1)
  • Techniques: interferometric

ASJC Scopus subject areas

  • Astronomy and Astrophysics
  • Space and Planetary Science


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