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

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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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    Wright, M. C. H., De Pater, I., Forster, J. R., Palmer, P., Snyder, L. E., Veal, J. M., A'Hearn, M. F., Woodney, L. M., Jackson, W. M., Kuan, Y. J., & Lovell, A. J. (1998). Mosaicked images and spectra of J = 1 → 0 HCN and HCO+ emission from comet Hale-Bopp (1995 O1). Astronomical Journal, 116(6), 3018-3028.