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The Study of Comets at Radio Wavelengths

Published online by Cambridge University Press:  12 April 2016

J. Crovisier  and
F. P. Schloerb
J. Crovisier
Affiliation:
Observatoire de Paris-Meudon 92195 MeudonFRANCE
F. P. Schloerb
Affiliation:
Department of Physics and Astronomy, University of Massachusetts Amherst, MA 01003U.S.A.

Abstract

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Radio observations of comets complement studies at other wavelengths as well as providing certain kinds of unique information. Studies of continuum emission may probe the thermal emission of the nucleus and large-size dust particles. Spectroscopic observations of gas in the coma allow searches for parent molecular species that have no signatures in the optical spectral range. The 18-cm wavelength spectral lines of the OH radical now are relatively easy to detect, and observations of them permit long-term and short-term monitoring of the cometary gaseous output. Moreover, with the unique spectral resolution of radio techniques, aspects of the kinematics of the coma may be also studied, such as the gas expansion velocity and the anisotropy of gas production from the nucleus. In this review, we present recent results of cometary radio observations, and discuss what may be learned from such studies in the future.

Type
Section I: Observing Techniques and Interpretation
Information
International Astronomical Union Colloquium , Volume 116 , Issue 1: Comets in the Post-Halley Era , 1989 , pp. 149 - 173
Copyright
Copyright © Kluwer 1991

References

A’Hearn, M.F., Hoban, S., Birch, P.V., Bowers, C., Martin, R., and Klinglesmith, D.A. (1986) Cyanogen jets in comet Halley. Nature 324, 649–651 Google Scholar
Altenhoff, W.J., Batrla, W., Huchtmeier, W.K., Schmidt, J., Stumpff, P., and Walmsley, C.M. (1983) Radio observations of connet 1983d. Astron. Astrophys. 125, L19–L22 Google Scholar
Altenhoff, W.J., Huchtmeier, W.K., Schmidt, J., Schraml, J.B., Stumpff, P., and Thum, C. (1986) Radio continuum observations of comet Halley. Astron. Astrophys. 164, 227–230 Google Scholar
Altenhoff, W.J., Huchtmeier, W.K., Kreysa, E., Schmidt, J., Schraml, J.B., and Thum, C. (1989) Radio continuum observations of comet Halley at 250 GHz. Astron. Astrophys. 222, 323–328.Google Scholar
Alurkar, S.K., Bhonsle, R.V., and Sharma, A.K. (1986) Radio observations of PKS2314+03 during occultation by comet Halley. Nature 322, 439–441 CrossRefGoogle Scholar
Ananthakrishnan, S., Bhandari, S.M., and Pramesh, R.A. (1975) Occultation of radio source PKS 2025-15 by comet Kohoutek (1973f). Astrophys. Space Sci. 37, 275–282 Google Scholar
Ananthakrishnan, S., Manoharan, P.K., and Venugopal, V.R. (1987) Occultation observations of compact radio sources through comet Halley’s plasma tail. Nature 329, 698–700 Google Scholar
Bajaja, E., Amal, E.M., Cersosimo, J.C., Colomb, F.R., Martin, M.C., Mazzaro, J., Morras, R., Olalde, J. C., Poppel, W.G.L., Silva, A.M., Mirabel, I.F., and Boriakoff, V. (1987a) Comet Halley: OH absorption of galactic background radio sources. Astrophys. J. 313, 906–909 Google Scholar
Bajaja, E., Morras, R., Poppel, W.G.L., Cersosimo, J.C., Martin, M.C., Mazzaro, J., Olalde, J.C., Silva, A., Arnal, M.E., Colomb, F.R., Mirabel, I.F., and Boriakoff, V. (1987b) Observation of the OH 1667 MHz line toward comet Halley from the southern hemisphere. Astrophys. J. 322, 549–558 Google Scholar
Baum, S., and Hoban, S. (1986) A search for the millimeter wave transitions of CO+ in comet P/Halley. Icarus 67, 515–519 Google Scholar
Berulis, I.I., Zinchenko, I.G., Losovskii, B. Ya., Sorochenko, R.L., and Tolmachev, A.M. (1987) A search for millimeter-wave H2O and HC3N emission from comet Halley (in Russian). Pisma Astron. Zh. 13, 526–529 (English translation: Sov. Astron. Lett. 13, 217-218)Google Scholar
Biraud, F., Bourgois, G., Crovisier, J., Fillit, R., Gérard, E., and Kazés, I. (1974) OH observation of comet Kohoutek (1973f) at 18 cm wavelength. Astron. Astrophys. 34, 163–166 Google Scholar
Bird, M.K., Huchtmeier, W.K., von Kap-herr, A., Schmidt, J., and Walmsley, C.M. (1987) Searches for parent molecules at MPIfR. in “Cometary Radio Astronomy,” Proceedings of an NRAO Workshop, Irvine, W.M., Schloerb, F.P., and Tacconi-Garman, L.E. (Eds.), Green Bank WV, USA. p. 85–89 Google Scholar
Bockelée-Morvan, D. (1987) A model for the excitation of water in comets. Astron. Astrophys. 181, 169–181 Google Scholar
Bockelée-Morvan, D., Bourgois, G., Crovisier, J., and Gérard, E. (1989) Comet Okazzaki-Levy-Rudenko (1989r) IAU Circular No. 4882 Google Scholar
Bockelée-Morvan, D., and Crovisier, J. (1985) Possible parents for the cometary CN radical: Photochemistry and excitation conditions. Astron. Astrophys. 151, 90–100 Google Scholar
Bockelée-Morvan, D., and Crovisier, J. (1987) The role of water in the thermal balance of the coma. In “Symposium on the Diversity and Similarity of Comets”, ESA SP-278, 235–240 Google Scholar
Bockelée-Morvan, D., Crovisier, J., Baudry, A., Despois, D., Perault, M., Irvine, W.M., Schloerb, F.P., and Swade, D. (1984) Hydrogen cyanide in comets: Excitation conditions and radio observations of comet IRAS-Araki-Alcock 1983d. Astron. Astrophys. 141, 411–418 Google Scholar
Bockelée-Morvan, D., Crovisier, J., Despois, D., Forveille, T., Gérard, E., Schraml, J., and Thum, C.. (1987) Molecular observations of comets P/Giacobini-Zinner 1984e and P/Halley 1982i at millimetre wavelengths. Astron. Astrophys. 180, 253–262 Google Scholar
Bockelée-Morvan, D., Crovisier, J., and Gerard, E. (1989) Retrieving the coma gas expansion velocity from cometary radio OH line profiles. In “Asteroids, Comets, Meteors III,” Lagerkvist, C-I, Rickman, H., Lindblad, B.A., and Lindgren, M. (Eds.), Uppsala, Sweden, pp. 267–270 Google Scholar
Bockelée-Morvan, D., and Gerard, E. (1984) Radio observations of the hydroxyl radical in comets with high spectral resolution. Kinematics and asymmetries of the OH coma in C/Meier (1978 XXI), C/Bradfleld (1979 X), and C/Austin (1982g). Astron. Astrophys. 131, 111–122 Google Scholar
Bystrova, N.V., Golubchin, G.S., Gosachinskii, I.V., Morozov, A.S., Nizhel’skaya, E.K., and Yudaeva, N.A. (1987) Observations of hydroxyl in comet Halley (in Russian). Pisma Astron Zh. 13, 1100–1103 (English translation: Sov. Astron. Lett. 13, 464-465)Google Scholar
Campbell, D.B. (1990) Radio studies: Radar. In “Comets in the Post-Halley Era,” in press.Google Scholar
Campbell, D.B., Harmon, J.K., and Shapiro, I.I., (1989) Radar observations of comet Halley. Astrophys. J. 338, 1094–1105 Google Scholar
Chin, G., and Weaver, H.A. (1984) Vibrational and rotational excitation of CO in comets: Nonequilibrium calculations. Astrophys. J. 285, 858–869 Google Scholar
Colom, P. (1989) Observations radio du radical OH dans la comete de Halley: Variations temporelles et anisotropie de la production gazeuse. Thesis, Universite Paris VII Google Scholar
Colom, P., Despois, D., Paubert, G., Bockelée-Morvan, D., Crovisier, J., and Gérard, E. (1989) Periodic comet Brorsen-Metcalf (1989o). IAU Circular No. 4851 Google Scholar
Colom, P., and Gérard, E. (1988) A search for periodicities in the OH radio emission of comet P/Halley (1986 III). Astron. Astrophys. 204, 327–336 Google Scholar
Colom, P., Gerard, E., and Crovisier, J. (1990) A study of the non-gravitational forces on comet Halley nucleus from the observations of the OH radio lines. In “Asteroids, Comets, Meteors III,” Lagerkvist, C-I, Rickman, H., Lindblad, B.A., and Lindgren, M. (Eds.), Uppsala, Sweden, pp. 293–296 Google Scholar
Combes, M. et al. (1988) The 2.5 to 12 microns spectrum of comet Halley from the IKS-VEGA experiment. Icarus 76, 404–436 CrossRefGoogle Scholar
Combi, M.R., and Delsemme, A.H. (1980) Neutral cometary atmospheres. I. An average random walk model for photodissociation in comets. Astrophys. J. 237, 633–640 CrossRefGoogle Scholar
Combi, M.R., and Smyth, W.H. (1988) Monte Carlo particle-trajectory models for neutral cometary gases. I. Models and equations. Astrophys. J. 327, 1026–1043 CrossRefGoogle Scholar
Crifo, J.F. (1989) Collisional coma models: An unorthodox overview. Adv. Space Res. 9, (3)197-(3)211 CrossRefGoogle Scholar
Cordes, J., Falchi, A., Tofani, G., Lewis, B.M., and Terzian, Y. (1986) Radio OH observations of Halley’s comet. In “20th ESLAB Symposium on the Exploration of Halley’s Comet”, ESA SP-250, Vol.3, 113–115 Google Scholar
Crovisier, J. (1984) The water molecule in comets: Fluorescence mechanisms and thermodynamics of the inner coma. Astron. Astrophys. 130, 361–372 (erratum 135, 197)Google Scholar
Crovisier, J. (1985) Searching for cometary parent molecules at radio wavelengths. Astron. J. 90, 670–674 Google Scholar
Crovisier, J. (1986) Sub-millimetre cometary spectroscopy. In “ESA Workshop on a Space-Borne Sub-Millimetre Astronomy Mission”, ESA SP-260, 57–65 Google Scholar
Crovisier, J. (1987) Rotational and vibrational synthetic spectra of linear parent molecules in comets. Astron. Astrophys. Suppl. Series 68, 223–258 Google Scholar
Crovisier, J. (1989) The photodissociation of water in cometary atmospheres. Astron. Astrophys. 213, 459–464 Google Scholar
Crovisier, J., Despois, D., Bockelée-Morvan, D., Gérard, E., Johansson, L.E.B., Ekelund, L., Winnberg, A., Ge, W., Irvine, W.M., Kinzel, W.M., Schloerb, F.P., and Swade, D.A. (1990) A search for the 3-mm lines of HCN in comet Wilson 1987 VII. In “Asteroids, Comets, Meteors III,” Lagerkvist, C-I, Rickman, H., Lindblad, B.A., and Lindgren, M. (Eds.), Uppsala, Sweden, pp.301–304 Google Scholar
Crovisier, J., and Encrenaz, T. (1983) Infrared fluorescence of molecules in comets: The general synthetic spectrum. Astron. Astrophys. 126, 170–182 Google Scholar
Crovisier, J., and Le Bourlot, J. (1983) Infrared and microwave fluorescence of carbon monoxyde in comets. Astron. Astrophys. 123, 61–66 Google Scholar
Delsemme, A.H. (1982) Chemical composition of cometary nuclei. In “Comets”, Wilkening, L L (Ed.), The University of Arizona Press, Tucson, Arizona, pp. 85–130 Google Scholar
Delsemme, A.H., and Miller, D. C. (1971) Physico-chemical phenomena in comets - III the continuum of comet Burnham (1960 II). Planet. Space Sci. 19, 1229–1257 Google Scholar
de Pater, I., Palmer, P., and Snyder, L. E. (1986) The brightness distribution of OH around comet Halley. Astrophys. J. 304, L33–L36 Google Scholar
de Pater, I., Palmer, P., and Snyder, L.E. (1990) A review of radio interferometrie imaging of comets. In “Comets in the Post-Halley Era,” in pressGoogle Scholar
dePater, I., Wade, C.M., Houpis, H.L.F., and Palmer, P. (1985) The nondetection of continuum radiation from comet IRAS-Araki-Alcock (1983d) at 2- to 6-cm wavelengths and its implication on the icy-grain halo theory. Icarus 62, 349–359 Google Scholar
Despois, D., Crovisier, J., Bockelée-Morvan, D., Schraml, J., Forveille, T., and Gérard, E. (1986) Observations of hydrogen cyanide in comet Halley. Astron. Astrophys. 160, L11–L12 Google Scholar
Despois, D., Gérard, E., Crovisier, J., and Kazés, I. (1981) The OH radical in comets: Observation and analysis of the hyperfine microwave transitions at 1667 MHz and 1665 MHz. Astron. Astrophys. 99, 320–340 Google Scholar
Duncan, R.A., Norris, R.P., Forster, J.R., Stewart, R.T., and McDonnell, D. (1986) Observations of 18 cm OH emission and absorption from Halley’s comet. Proc. Astron. Soc. Australia 6, 301–303 Google Scholar
Dobrovolski, O.V. (1958) Radio Emission of comets (in Russian). Bull. Instit. Astroflz. Akad. Nauk. Tadzh. SSR. No. 26 Google Scholar
Elitzur, M. (1981) On pumping of the OH ground state in comets. Astrophys. J. 246, 354–359 CrossRefGoogle Scholar
Falchi, A., Gagliardi, L., Palagi, F., Tofani, G., and Comoretto, G. (1987) 10.7 GHz continuum observations of comet P/Halley. Astron. Astrophys. 187, 462–464 Google Scholar
Festou, M.C. (1981) The density distribution of neutral compounds in cometary atmospheres. I. Models and equations. Astron. Astrophys. 95, 69–79 Google Scholar
Gait, J. (1987) Monitoring the 1.667 GHz OH line in comet Halley. Astron. J. 93, 747–752 Google Scholar
Gaylard, M.J. (1987) Comet Halley hydroxyl observations at 18-cm during the transit of the galactic plane and Centauras A. In “Cometary Radio Astronomy,” Proceedings of an NRAO Workshop, Irvine, W. M., Schloerb, F.P., and L. E., Tacconi-Garman (Eds.) Green Bank, WV, USA pp. 109–119 Google Scholar
Gérard, E. (1985) An estimate of the magnetic fleld strength in the OH coma of comet Austin (1982 VI). Astron. Astrophys. 146, 1–10 Google Scholar
Gérard, E. (1990) On the discrepancy between OH production rates deduced from radio and UV observations of comets. IA comparative study of radio and UV observations of P/Halley 1986 III in late November and early December 1985. Astron. Astrophys, in press.Google Scholar
Gérard, E., Bockelée-Morvan, D., Bourgois, G., Colom, P., and Crovisier, J. (1987) 18-cm wavelength radio monitoring of the OH radical in comet P/Halley 1982i. Astron. Astrophys. 187, 455–461 Google Scholar
Gérard, E., Bockelée-Morvan, D., Bourgois, G., Colom, P., and Crovisier, J. (1988) Observations of the OH radio lines in comet P/Giacobini-Zinner 1985 XIII. Astron. Astrophys. Suppl. Series 74, 485–495 Google Scholar
Gerard, E., Bockelée-Morvan, D., Bourgois, G., Colom, P., and Crovisier, J. (1989) Observations of the OH radio lines in comet P/Halley 1986 III. Astron. Astrophys. Suppl. Series 77, 379–410 Google Scholar
Gibson, D.M., and Hobbs, R.W. (1981) On the microwave emission from comets. Astrophys. J. 248, 863–866. (Errata, Astrophys. J. 269, 805-806)Google Scholar
Goldstein, R.M., Jürgens, R.F., and Sekanina, Z. (1984) A radar study of comet IRAS-Araki-Alcock 1983d. Astron. J. 89, 1745–1754 Google Scholar
Gulkis, S., Batelaan, P.D., Frerking, M.A., Klein, M.J., Kuiper, T.B.H., Pickett, H.M., Schaefer, M.M., Wannier, P., Bockelée-Morvan, D., Crovisier, J., Encrenaz, P.J., Zimmermann, P., and Destombes, J.L. (1989) Search for water in comet P/Halley at 380 GHz. Astron. Astrophys. 213, 465–468 Google Scholar
Harmon, J.K., Campbell, D.B., Hine, A. A., Shapiro, I.I., and Marsden, B.G. (1989) Radar observations of comet IRAS-Araki-Alcock 1983d. Astrophys. J. 338, 1071–1093 Google Scholar
Haser, L. (1957) Distribution d’intensité dans la tete d’une comete. Bull. Acad. Roy. Soc. Belgique (Classe des Sciences) 43, 740–750 Google Scholar
Hoban, S., and Baum, S. (1987) A VLA search for 2-cm continuum radiation from comet Halley. Icarus 70, 264–268 Google Scholar
Hobbs, R.W., Brandt, J.C., and Maran, S.P. (1977) Microwave continuum radiation from Comet West (1975n). Astrophys. J. 218, 573–578 CrossRefGoogle Scholar
Hobbs, R.W., Maran, S.P., Brandt, J.C., Webster, W.J., and Krishna Swamy, K.S. (1975) Microwave continuum radiation from comet Kohoutek 1973f: Emission from the icy-grain halo? Astrophys. J. 201, 749–755 Google Scholar
Hodges, R.R. (1990) Monte Carlo simulation of nonadiabatic expansion in cometary atmospheres: Halley. Icarus, in pressGoogle Scholar
Huebner, W.F., Snyder, L.E., and Buhl, D. (1974) HCN radio emission from comet Kohoutek (1973f). Icarus 23, 580–584 Google Scholar
Irvine, W.M. et al. (1984) Radioastronomical observations of comets IRAS-Araki-Alcock (1983d) and Sugano-Saiguza-Fujikawa (1983e). Icarus 60, 215–220 Google Scholar
Irvine, W.M., Schloerb, F.P., and Tacconi-Garman, L.E. (Eds). (1987) “Cometary Radio Astronomy,” Proceedings of an NRAO Workshop, Green Bank, WV, USA Google Scholar
Jackson, W.M., Clark, T., and Donn, B. (1976) Radio detection of HO in comet Bradfleld (1974b). In “The Study of Comets,” NASA SP-393, 272–280 Google Scholar
Jewitt, D., and Luu, J. (1989) Periodic Comet Brorsen-Metcalf (1989o). IAU Circular No.4852 Google Scholar
Krankowsky, D. (1990) The composition of comets. In “Comets in the Post-Halley Era,” in pressGoogle Scholar
Lämmerzahl, P. et al. (1987) Expansion velocity and temperatures of gas and ions measured in the coma of comet P/Halley. Astron. Astrophys. 187, 169–173 Google Scholar
Larson, H.P., Mumma, M.J., and Weaver, H.A. (1987) Expansion velocity and temperatures of gas and ions in the coma of comet P/Halley. Astron. Astrophys. 187, 166–173 Google Scholar
Luo, X., Zhou, T., Yao, D., Du, S., Qian, Z., Ji, D., and Zhang, W. (1988) Radio observations of the OH line in comet Halley. Act. Astrophys. Sin. 8, 223–229. (English translation: Chin. Astron. Astrophys. 12, 324-327)Google Scholar
Luo, X., Zhou, T., Yao, D., Du, S., Qian, Z., Ji, D., and Zhang, W. (1988) Radio observations of the OH line in comet Halley. Vistas in Astronomy 31, 161–163 Google Scholar
Mies, F.H. (1974) Ultraviolet fluorescent pumping of OH 18-centimeter radiation in comets. Astrophys. J. 191, L145–L148 Google Scholar
Rickman, H. (1986) Masses and densities of comets Halley and Kopff. In “Comet Nucleus Sample Return”, ESA SP-249, 195–205 Google Scholar
Rickman, H. (1989) The nucleus of comet Halley: Surface structure, mean density, gas and dust density. Adv. Space Res. 2, (3)59-(3)71 Google Scholar
Roesler, F.L., Scherb, F., Magee, K., Harlander, J., Reynolds, R.J., Yelle, R.V., Broadfoot, A.L., and Oliversen, R.J. (1986) High spectral resolution line profdes and images of comet Halley. Adv. Space Res. 5 (No 12), 279–282 Google Scholar
Sagdeev, R.Z., Elyasberg, P.E., and Moroz, V.I. (1988) Is the nucleus of comet Halley a low density body ? Nature 331, 240–242 Google Scholar
Scalise, E. Jr., Montero do Vale, J.L., Vila Boas, J.W.S., Abraham, Z., Botti, L.C.L., Tateyama, C.E., Cancoro, A.C.O., Kaufman, P., and Del Ciampo, L.F. (1987) Radio observations of comet Halley at 22 and 43 GHz. In “Cometary Radio Astronomy,” Proceedings of an NRAO Workshop, Irvine, W.M., Schloerb, F.P., and Tacconi-Garman, L. E. (Eds.), Green Bank, WV, USA, pp. 27–30 Google Scholar
Schliecher, D.G. (1983) The fluorescence of cometary OH and CN. Ph D thesis, University of Maryland Google Scholar
Schleicher, D.G., and A’Hearn, M.F. (1988) The fluorescence of cometary OH. Astrophys. J. 331, 1058–1077 Google Scholar
Schloerb, F.P. (1988) Collisional quenching of cometary emission in the 18 centimeter OH transitions. Astrophys. J. 332, 524–530 CrossRefGoogle Scholar
Schloerb, F.P., Claussen, M.J., and Tacconi-Garman, L.E. (1987) OH radio observations of comet P/Halley. Astron. Astrophys. 187, 469–474 Google Scholar
Schloerb, F.P., and Gérard, E. (1985) Models of cometary emission in the 18-cm OH transitions: The predicted behavior of comet Halley. Astron. J. 90, 1117–1135 Google Scholar
Schloerb, F.P., Kinzel, W.M., Swade, D. A., and Irvine, W.M. (1986) HCN production rates from comet Halley. Astrophys. J. 310, L55–L60 Google Scholar
Schloerb, F.P., Kinzel, W.M., Swade, D.A., and Irvine, W.M. (1987) Observations of HCN in comet P/Halley. Astron. Astrophys. 187, 475–480 Google Scholar
Silva, A.M., and Mirabel, I.F. (1988) Gaseous outbursts in comet P/Halley. A model for the dissociation of the OH radical. Astron. Astrophys. 201, 350–354 Google Scholar
Snyder, L.E. (1982) A review of radio observations of comets. Icarus 51, 1–24 Google Scholar
Snyder, L.E. (1986) The 18 cm OH lines in comets: Preparation for Halley. Astron. J. 91, 163–170 Google Scholar
Snyder, L.E., Palmer, P., and de Pater, I. (1989) Radio detection of formaldehyde emission from comet Halley. Astron. J. 97, 246–253 Google Scholar
Snyder, L.E., Palmer, P., and Wade, C.M. (1983) An upper limit to the microwave continuum radiation from comet Austin (1982g). Astrophys. J. 269, L21–L23 Google Scholar
Snyder, L.E., Palmer, P., and de Pater, I. (1990) Observations of formaldehyde in comet Machholz (1988J) Icarus, in pressGoogle Scholar
Swade, D.A., Schloerb, F.P., Irvine, W.M., and Kinzel, W.M. (1987) Search for molecules in comet Halley at millimeter wavelengths. In “Cometary Radio Astronomy,” Proceedings of an NRAO Workshop, Irvine, W.M., Schloerb, F.P., and Tacconi-Garman, L. E. (Eds.), Green Bank, WV, USA, pp. 79–83 Google Scholar
Tacconi-Garman, L.E. (1989) Ph D thesis, University of Massachusetts Google Scholar
Tacconi-Garman, L.E., Schloerb, F.P., and Claussen, M.J. (1990) A kinematic model for cometary comae. In “Asteroids, Comets, Meteors III,” Lagerkvist, C-I, Rickman, H., Lindblad, B.A., and Lindgren, M. (Eds.), Uppsala, Sweden, pp. 455–458 Google Scholar
Turner, B.E. (1974) Detection of OH at 18-centimeter wavelength in comet Kohoutek (1973f). Astrophys. J. 189, L137–L139 Google Scholar
van Dishoeck, E.F., and Dalgarno, A. (1984) The dissociation of OH and OD in comets by solar radiation. Icarus 59, 305–313 Google Scholar
Walmsley, C.M. (1985) The interpretation of the radio continuum emission from comet 1983d (IRAS-Araki-Alcock). Astron. Astrophys. 142, 437–440 Google Scholar
Weaver, H.A., Mumma, M.J., and Larson, H.P. (1990) Infrared spectroscopy of cometary parent molecules. In “Comets in the Post-Halley,” in pressGoogle Scholar
Winnberg, A., Ekelund, L., and Ekelund, A. (1987) Detection of HCN in comet P/Halley. Astron. Astrophys. 172, 335–341 Google Scholar
Wootten, A., Boulanger, F., Bogey, M., Combes, F., Encrenaz, P.J., Gerin, M., and Ziurys, L. (1986) A search for interstellar H30+ . Astron. Astrophys. 166, L15–L18 Google Scholar