Abstract
Star counts, from measurements made by the GALAXY measuring machine, in unit B magnitude intervals were made in nine regions, each of 1.75 square degrees distributed about (l, b)= (140°, 0°). The mean density function and the mean variation of interstellar absorption with distance for the various areas were determined using a combination of theoretical and observed cumulative Wolf diagrams. For the same regions multi-colour (UBV) photographic photometry was used to identify early type stars. The distribution of these stars shows three main peaks which correspond well in distance with the Perseus, α- and β-spiral arms found by Verschuur from radio measurements of neutral hydrogen. The pattern made by the stellar arms in the (l, r) plane shows a discontinuity nearl=140°. From a consideration of both the star counts and the distribution of the reddened early type stars it is suggested that the cause of the discontinuity is a cloud with 0 m. 7 total obscuration situated much nearer to the Sun than the Perseus arm and terminating on one side atl=140°.
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References
Allen, C. W.: 1963,Astrophysical Quantities, 2nd Edn., University of London.
Becker, W.: 1973,The Role of Schmidt Telescopes in Astronomy, Hamburg.
Bok, B. J.: 1937,The Distribution of the Stars in Space, University of Chicago Press, Chicago, Ill., U.S.A.
Crézé, M.: 1972,Astron. Astrophys. 21 85.
Dodd, R. J.: 1972,Astron. J. 77, 306.
Dodd, R. J.: 1973, Ph.D. Thesis. Dept. of Astronomy, University of Edinburgh.
Dodd, R. J.: 1974a,Publ. Roy. Obs. Edinburgh 9, 63.
Dodd, R. J.: 1974b,Astrophys. Space Sci. 26, 513.
Fernie, J. D.: 1968,Astron. J. 73, 995.
FitzGerald, M. P.: 1968,Astron. J. 73, 983.
Goldberg, B.: 1975, Private communication.
Humphreys, R.: 1970,Astron. J. 75, 602.
Johnson, H. L.: 1966,Ann. Rev. Astron. Astrophys. 4, 193.
Kerr, F. J. and Westerhout, G.: 1965, in Blaauw, A. and Schmidt, M. (eds.),Galactic Structure, University of Chicago, Press, p. 167.
Kraft, R. P. and Schmidt, M.: 1963,Astrophys. J. 137, 249.
McCuskey, S. W. and Houk, N.: 1971,Astron. J. 76, 1117.
Mathewson, D. S. and Ford, V. L.: 1970,Mem. Roy. Astron. Soc. 74, 139.
Mihalas, D. and Routley, P. M.: 1968,Galactic Astronomy, W. A. Freeman and Co., San Francisco.
Moffat, A. F. J. and Vogt, N.: 1973,Astron. Astrophys. 23, 317.
Neckel, Th.: 1967,Veröffentl. Landessternw. Heidelberg-Königstuhl,19.
Pratt, N. M.: 1971,Publ. Roy. Obs. Edinburgh 8, 109.
Reddish, V. C.: 1967,Nature 213, 1107.
van Rhijn, P. J.: 1936,Groningen Publ. 47.
Rohlfs, K.: 1967,Z. Astrophys. 66, 225.
Sim, M. E.: 1968,Publ. Roy. Obs. Edinburgh 6, 123.
Smith, L. F.: 1968,Monthly Notices Roy. Astron. Soc. 141, 317.
Verschuur, G. L.: 1973a,Astron. Astrophys. 24, 193.
Verschuur, G. L.: 1973b,Astron. Astrophys. 27, 73.
Walker, G. S.: 1971,Publ. Roy. Obs. Edinburgh 8, 109.
Wolf, M.: 1923,Astron. Nachr. 219, 109.
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Dodd, R.J. On the galactic plane discontinuity nearl=140°. Astrophys Space Sci 44, 85–99 (1976). https://doi.org/10.1007/BF00650474
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DOI: https://doi.org/10.1007/BF00650474