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The interpretations of ultraviolet observations of comets

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Summary

Ultraviolet observations of comets from above the Earth's atmosphere have provided excellent new results and improved older ground based observations (OH) by an order of magnitude. Satellites are especially suitable because long integration times and observations during extended time intervals are possible.

The existing cometary Lα observations have confirmed the relatively high overall gas production rates on the order of 1030 molecule s−1. The results strongly support the concept of an icy conglomerate solid cometary nucleus. Additional observations of hydroxyl and oxygen favor water to be one of the most abundant molecules in comets. The observations are in agreement with the predominent role of water in the evaporation process of the nuclear ices but are not proof in themselves.

Water did not outnumber other consitutents by orders of magnitude in comets Bennett and Kohoutek. At least in these comets, carbon-containing molecules were possibly as numerous as water. Determination of the carbon scale length is necessary for a more quantitative statement.

A hydrogen velocity of 7–9 km s−1 was observed in comet Bennett as well as in comet Kohoutek for a variety of heliocentric distances and varying production rates. Determinations of the outflow velocity from Lα isophotes agree with line profile observations of Lα and Hα. Hydroxyl may constitute the main source for the hydrogen atoms with v H ∼- 8 km s−1. The decay process, however, leading to this particular velocity is not yet known. Possibly a large portion of the OH radicals do not decay into hydrogen atoms or at least not into slow ones. If the high velocity component of 20 km s−1 or more comprises a larger amount (up to 50%), most of the quoted hydrogen production rates must be revised upward.

The intrinsic cometary brightness is only a very crude indicator of a comet's actual gas production rate as shown by comparison of comets Bennett and TSK. Comets can be successfully used as (extra ecliptic) space probes to measure interplanetary quantities, e.g., the curvature of the extended hydrogen clouds can be used for the absolute determination of the solar emission independent of instrumental calibration. Generally time dependent hydrogen density models must be used for the interpretation. The strength of the ultraviolet Lα emission favors its measurement as a standard procedure for the observation of comets (possibly together with OH (3090 Å)). These observations provide the most accurate results on the total cometary gas production rate and its variation with heliocentric distance.

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References

  • Angione R. J., Gates, B., Henize, K. G., and Roosen, R. G.: 1975, Icarus 24, 111.

    Google Scholar 

  • Arpigny, C.: 1965, Acad. Roy. Belgique, 66.

  • Belyaev, V. A., Brezhnev, B. G., and Erastov, E. M.: 1967, Soviet Phys. JETP 25, 777.

    Google Scholar 

  • Bertaux, J.-L. and Blamont, J.: 1970, Compt. Rend. Acad. Sci. 270, 1581.

    Google Scholar 

  • Bertaux, J.-L., Blamont, J., and Festou, M.: 1973, Astron. Astrophys. 25, 415.

    Google Scholar 

  • Beyer, M.: 1972, Astron. Nachr. 293, 241.

    Google Scholar 

  • Biermann, L.: 1951, Z. Astrophys. 29, 274.

    Google Scholar 

  • Biermann, L. and Treffez, E.: 1964, Z. Astrophys. 59, 1.

    Google Scholar 

  • Biermann, L.: 1968, JILA Report No. 93.

  • Biermann, L. and Diercksen, G.: 1973, Proc. 5th International Symposium on Origin of Life, Barcelona or Max-Planck-Institut für Physik und Astrophysik, Munich, Report.

  • Biraud, F., Burgois, G., Grovisier, J., Fillit, R., Gerard, E., and Kazes, I.: 1974, Astron. Astrophys. 34, 163.

    Google Scholar 

  • Blamont, J. E. and Festou, M.: 1974, Icarus 23, 538.

    Google Scholar 

  • Bobrovnikoff, N. T.: 1931, Publ. Lick Obs. 17, 404.

    Google Scholar 

  • Bobrovnikoff, N. T.: 1942, Phys. Rev. 14, 172.

    Google Scholar 

  • Bohlin, J. D., Drake, J. F., Jenkins, E. B., and Keller, H. U.: 1975, Proceedings of IAU Colloquium No. 25, Greenbelt, Maryland, 1974, in press.

  • Brandt, J. C., Harrington, R. S., and Roosen, R. G.: 1973, Astrophys. J. 184, 27.

    Google Scholar 

  • Broadfoot, A. L., Belton, M. J. S., McElroy, M. B., and Kumar, S.: 1974, Comet Kohoutek Workship, Huntsville, Alabama.

  • Brosowski, B. and Wegmann, R.: 1972, Max-Planck-Institut für Physik und Astrophysik, Report No. MPI/PAE-Astro. 46.

  • Cameron, A. G. W.: 1972, CERN Meeting on the Origin of the Solar System, Nice, France.

    Google Scholar 

  • Carrington, T.: 1964, J. Chem. Phys. 41, 2012.

    Google Scholar 

  • Carruthers, G. R., Opal, C. B., Page, T. L., Meier, R. R., and Prinz, D. K.: 1974, Icarus 23, 526.

    Google Scholar 

  • Carruthers, G. R., Keller, H. U., Meier, R. R., Opal, C. B., and Page, T. L.: 1975, in preparation.

  • Code, A. D.: 1970, paper presented at Commission 15 meeting General Assembly, IAU.

  • Code, A. D., Houck, T. E., and Lillie, C. F.: 1970, IAU Circ. 2201.

  • Code, A. D., Houck, T. E., and Lillie, C. F.: 1972, The Scientific Results from Orbiting Astronomical Observatory (OAO-2), Ed. by A. D. Code, NASA SP-310, 109.

  • Czarny, J., Felenbok, P., and Lefebvre-Brion, H.: 1971, J. Phys. B.: Atom. Molec. Phys. 4, 124.

    Google Scholar 

  • Dalgarno, A.: 1975, private communication.

  • Delsemme, A. H. and Swings, P.: 1952, Ann. Astrophys. 15, 1.

    Google Scholar 

  • Delsemme, A. H.: 1966, Mem. Soc. Roy. Sci. Liège 12, 77.

    Google Scholar 

  • Delsemme, A. H. and Miller, D. C.: 1970, Planet. Space Sci. 18, 717.

    Google Scholar 

  • Delsemme, A. H.: 1973, Astrophys. Letters 14, 163.

    Google Scholar 

  • Delsemme, A. H. and Moreau, J. L.: 1973, Astrophys. Letters 14, 181.

    Google Scholar 

  • Delsemme, A. H., Rud, D. A.: 1973, Astron. Astrophys. 28, 1.

    Google Scholar 

  • Dolginov, A. Z., Gnedin, Yu. N., and Novikov, G. G.: 1972, Kosmicheskie Issledovaniya 10, 793.

    Google Scholar 

  • Drake, J. F., Jenkins, E. B., Bertaux, J. L., Festou, M., and Keller, H. U.: 1975, Astron. Astrophys., to be published

  • Feldman, P. D., Takacs, P. Z., Fastie, W. G., and Donn, B.: 1974, Science 185, 705.

    Google Scholar 

  • Feldman, P. D., Opal, C. B., Meier, R. R., and Nicolas, K. R.: 1975, Proceedings of IAU Colloquium No. 25, Greenbelt, Maryland, 1974, in press.

  • Felenbok, P.: 1963, Ann. Astrophys. 26, 393.

    Google Scholar 

  • Finson, M. L. and Probstein, R. F.: 1968, Astrophys. J. 154, 327 and 353.

    Google Scholar 

  • Gnedin, Yu. N., Dolginov, A. Z., and Novikov, G. G.: 1971, Soviet Astronomy 14, 700 (translation).

    Google Scholar 

  • Greenstein, J. L.: 1958, Astrophys. J. 128, 106.

    Google Scholar 

  • Hall, L. A., and Hinteregger, A. E.: 1970, J. Geophys. Res. 75, 6954.

    Google Scholar 

  • Haser, L.: 1957, Bull. Acad. Roy. Sci. Belgique 43, 740.

    Google Scholar 

  • Haser, L.: 1966, Congrès Colloques L'Université de Liège 37, 233.

    Google Scholar 

  • Hasted, J. B.: 1964, Physics of Atomic Collisions, Butterworth, London, England.

    Google Scholar 

  • Hinze, J.: 1975, private communication.

  • Huebner, W. F.: 1965, Z. Astrophys. 63, 22.

    Google Scholar 

  • Huebner, W. F., Snyder, L. E., and Buhl, D.: 1974, Icarus 23, 580.

    Google Scholar 

  • Huppler, D., Reynolds, R. J., Roesler, F. L., Scherb, F., and Trauger, J.: 1975, Astrophys. J., in press.

  • Ip, W.-H., and Mendis, D. A.: 1974, Astrophys. Space Sci. 26, 153.

    Google Scholar 

  • Jackson, W. M., and Donn, B.: 1968, Icarus 8, 270.

    Google Scholar 

  • Jackson, W. M., Clark, T., and Donn, B.: 1975, Proceedings of IAU Colloquim No. 25, Greenbelt, Maryland, 1974, in press.

  • Jenkins, E. B., and Wingert, D. W.: 1972, Astrophys. J. 174, 697.

    Google Scholar 

  • Jockers, K., and Lüst, Rh.: 1973, Astron. Astrophys. 26, 113.

    Google Scholar 

  • Keller, H. U.: 1971a Mitt. Astron. Ges. 30, 143.

    Google Scholar 

  • Keller, H. U.: 1971b, Ph.D. dissertation, University Munich.

  • Keller, H. U.: 1973a, Astron. Astrophys. 23, 269.

    Google Scholar 

  • Keller, H. U.: 1973b, Astron. Astrophys. 27, 51.

    Google Scholar 

  • Keller, H. U.: 1973c, AIAA Proceedings, Ed. by E. Greenstadt, in press.

  • Keller, H. U., and Thomas, G. E.: 1973, Astrophys. J. L87.

  • Keller, H. U., and Lillie, C. F.: 1974, Astron. Astrophys. 34, 187.

    Google Scholar 

  • Keller, H. U., Bohlin, J. D., and Tousey, R.: 1975a, paper presented at Comet Kohoutek Workshop, Huntsville, Alabama, 1974, proceedings in press.

  • Keller, H. U., Bohlin, J. D., and Tousey, R.: 1975b, Astron. Astrophys. 38, 413.

    Google Scholar 

  • Keller, H. U., and Thomas, G. E.: 1975, Astron. Astrophys. 39, 7.

    Google Scholar 

  • Keller, H. U., and Lillie, C. F.: 1975, in preparation.

  • Keller, H. U. and Meier, R. R.: 1975, in preparation.

  • Keller, H. U.: 1975, Proceedings of IAU Colloquium No. 25, Greenbelt, Maryland, 1974, in press.

  • Lillie, C. F.: 1975, Proceedings of IAU Colloquium No. 25, Greenbelt, Maryland, 1974, in press.

  • Malaise, D.: 1970, Astron. Astrophys. 5, 209.

    Google Scholar 

  • Marsden, B. G., Sekanina, Z., and Yeomans, D. K.: 1973, Astron. J. 78, 211.

    Google Scholar 

  • Meier, R. R., and Mange, P.: 1973, Planet. Space. Sci. 21, 309.

    Google Scholar 

  • Meier, R. R.: 1975, Astron. Astrophys., to be published.

  • Mendis, D. A., Holzer, T. E., and Axford, W. J.: 1972, Astrophys. Space Sci. 15, 313.

    Google Scholar 

  • Mies, F. H.: 1974, Astrophys. J. 191, L145.

    Google Scholar 

  • Opal, C. B., Carruthers, G. R. Prinz, D. K., and Meier, R. R.: 1974, Science 185, 702.

    Google Scholar 

  • Opik, E. J.: 1973, Astrophys. Space Sci. 21, 307.

    Google Scholar 

  • Oppenheimer, M.: 1975, Astrophys. J. 196, 251.

    Google Scholar 

  • Page, T. L.: 1975, paper presented at Comet Kohoutek Workshop, Huntsville, Alabama, 1974, in press.

  • Palmer, H. B., and Naegeli, D. W.: 1973, J. Chem. Phys. 59, 994.

    Google Scholar 

  • Potter, A. E. and Del Duca, B.: 1964, Icarus 3, 103.

    Google Scholar 

  • Riegler, G. R.: 1974, private communication.

  • Sekanina, Z. and Miller, F. D.: 1973, Science 179, 565.

    Google Scholar 

  • Sekanina, Z.: 1975, Proceedings of IAU Colloquium No. 25, Greenbelt, Maryland, 1974, in press.

  • Shul'man, L. M.: 1970, Astrometrija Astrophysica 11, 15.

    Google Scholar 

  • Shul'man, L. M.: 1972, Dinamika Kometnich atmosfer-neutralnii gaz, Kiev.

  • Smith, W. H.: 1970, J. Chem. Phys. 53, 792.

    Google Scholar 

  • Stief, L. J.: 1966, J. Chem. Phys. 44, 277.

    Google Scholar 

  • Swings, P.: 1948, Astrophys. J. 108, 526.

    Google Scholar 

  • Swings, P. and Haser, L.: 1956, Atlas of Representative Cometary Spectra, Institut d'Astrophys., Liège, Belgium.

    Google Scholar 

  • Swings, P., Bosman-Crespin, D., and Arpigny, C.: 1960, Proceedings of Liège Symposium, p. 583.

  • Thomas, G. E.: 1975, AIAA Proceedings, Ed. by E. Greenstadt, in press.

  • Tolk, N. H., White, C. W., and Graedel, T. E.: 1970, Bull. Astron. Astrophys. Soc. 2, 349.

    Google Scholar 

  • Ulich, B. L., and Conklin, B. K.: 1974, Nature 248, 121.

    Google Scholar 

  • Vanysek, V.: 1971, Bull. Astron. Inst. Czech 22, 114.

    Google Scholar 

  • Wallis, M. K.: 1973, Astron. Astrophys. 24, 29.

    Google Scholar 

  • Wallis, M. K.: 1974, Monthly Notices Roy. Astron. Soc. 166, 181.

    Google Scholar 

  • Wehinger, P., Wyckoff, W.: 1975, Proceedings of IAU Colloquium No. 25, Greenbelt, Maryland, 1974, in press.

  • Welge, K. H. and Stuhl, F.: 1966, J. Chem. Phys. 46, 2440.

    Google Scholar 

  • Whipple, F. L.: 1950, Astrophys. J. 111, 375.

    Google Scholar 

  • Whipple, F. L.: 1951, Astrophys. J. 113, 464.

    Google Scholar 

  • Whipple, F. L.: 1972, Proceedings of IAU Symposium 45, p. 401, D. Reidel Publishing Co., Dordrecht, Netherlands.

    Google Scholar 

  • Wurm, K.: 1934, Z. Astrophys. 8, 281.

    Google Scholar 

  • Wurm, K.: 1935, Z. Astrophys. 9, 62.

    Google Scholar 

  • Wurm, K.: 1963, in B. M. Middlehurst and G. P. Kuiper (eds.), The Solar System 4, 173, University of Chicago Press.

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  1. Laboratory for Atmospheric and Space Physics, University of Colorado, 80302, Boulder, Colo., U.S.A

    H. U. Keller

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Dedicated to Professor L. Biermann in recognition of his inspiring guidance.

On leave of absence from Max-Planck-Institut für Physik und Astrophysik, Munich.

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Keller, H.U. The interpretations of ultraviolet observations of comets. Space Sci Rev 18, 641–682 (1976). https://doi.org/10.1007/BF00169520

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