Abstract
A diffuse cloud is defined as an interstellar cloud with typical H2 (or H) density of 10–100 cm−3 and typical visual extinction of a few magnitude. Physical and chemical conditions are significantly affected by interstellar ultraviolet radiation. Chemical compositions of diffuse clouds are summarized on the basis of observational results. Chemical processes in diffuse clouds are discussed for major chemical elements including C, O, and N, on the basis of timescales of chemical reactions. Since the timescale of photodissociation is very fast, chemical compositions of diffuse clouds are almost in chemical equilibrium. Observational results are compared with steady-state chemical models reported previously. Outstanding problems such as the CH+ problem, the H3 + problem, and diffuse interstellar bands are introduced.
Access this chapter
Tax calculation will be finalised at checkout
Purchases are for personal use only
References
E.K. Campbell, M. Holz, D. Gerlich, J.P. Maier, Nature 523, 322 (2015)
P. Crane, D.L. Lambert, Y. Sheffer, Astrophys. J. Suppl. 99, 107 (1995)
S.R. Federman, Astron. Astrophys. 257, 125 (1982)
B.H. Foing, P. Ehrenfreund, Nature 369, 296 (1994)
M. Gerin, M. De Luca, J. Black, et al., Astron. Astrophys. 518, L110 (2010)
B. Goddard, E. Falgarone, M. Gerin, P. Hily-Brant, M. De Luca, Astron. Astrophys. 520, A20 (2010)
M.L. Heger, Lick Obs. Bull. 10, 141 (1922)
N. Indriolo, B.J. McCall, Astrophys. J. 745, 91 (2012)
N. Indriolo, T.R. Geballe, T. Oka, B.J. McCall, Astrophys. J. 671, 1736 (2007)
E.B. Jenkins, Astrophys. J. 700, 1299 (2009)
P. Jenniskens, F.-X. Desert, Astron. Astrophys. Suppl. 106, 39 (1994)
D.L. Lambert, Y. Sheffer, S.R. Federman, Astrophys. J. 438, 740 (1995)
F. Le Petit, E. Roueff, E. Herbst, Astron. Astrophys. 417, 993 (2004)
D.C. Lis, J.C. Pearson, D.A. Neufeld, et al., Astron. Astrophys. 521, L9 (2010)
B.J. McCall, T.R. Geballe, K.H. Hinkle, T. Oka, Science 279, 1910 (1998)
B.J. McCall, K.H. Hinkle, T.R. Geballe, G.H. Moriarty-Schieven, N.J. Evans II, K. Kawaguchi, S. Takano, V.V. Smith, T. Oka, Astrophys. J. 567, 391 (2002)
B.J. McCall, M.M. Drosback, J.A. Thorburn, D.G. York, S.D. Friedman, L.M. Hobbs, B.L. Rachford, T.P. Snow, P. Sonnentrucker, D.E. Welty, Astrophys. J. 708, 1628 (2010)
D. McElroy, C. Walsh, A. J. Markwick, M. A. Cordiner, K. Smith, T. J. Millar, Astron. Astrophys. 550, A36 (2013). http://udfa.ajmarkwick.net/
P.W. Merrill, Publ. Astron. Soc. Pac. 46, 206 (1934)
D.A. Neufeld, J.R. Goicoechea, P. Sonnentrucker, et al., Astron. Astrophys. 521, L10 (2010)
L.-A. Nyman, Astron. Astrophys. 120, 307 (1983)
T. Oka, Phys. Rev. Lett. 45, 531 (1980)
T. Oka, D.E. Welty, S. Johnson, D.G. York, J. Dahlstrom, L.M. Hobbs, Astrophys. J. 773, 42 (2013)
N. Sakai, H. Maezawa, T. Sakai, K.M. Menten, S. Yamamoto, Astron. Astrophys. 546, A103 (2012)
P.J. Sarre, J. Mol. Spectrosc. 238, 1 (2006)
Y. Sheffer, M. Rogers, S.R. Federman, N.P. Abel, R. Gredel, D.L. Lambert, G. Shaw, Astrophys. J. 687, 1075 (2008)
T.P. Snow, B.J. McCall, Annu. Rev. Astron. Astrophys. 44, 367 (2006)
T.P. Snow, J.D. Destree, in ‘PAHs and the Universe’, 2011, ed. by C. Joblin, A.G.G.M. Tielens EAS Publ. Ser. 46, p. 341
P. Sonnentrucker, D.A. Neufeld, T.G. Phillips, et al., Astron. Astrophys. 521, L12 (2010)
J.A. Thorburn, L.M. Hobbs, B.J. McCall, T. Oka, D.E. Welty, S.D. Friedman, T.P. Snow, P. Sonnentrucker, D.G. York, Astrophys. J. 584, 339 (2003)
A.G.G.M. Tielens, in Proceedings IAU Symposium No. 297, eds by Cami, J., Cox, N.L.J., (2014) p. 399
A.G.G.M. Tielens, T.P. Snow, The diffuse interstellar bands (Kluwer, Dordrecht, 1995)
E.F. van Dishoeck, J.H. Black, Astrophys. J. Suppl. 62, 109 (1986)
V. Wakelam et al., Astrophys. J. Suppl. 199, 21 (2012)
G.A. Walker, D.A. Bohlender, J.P. Maier, E.K. Campbell, Astrophys. J. 812, L8 (2015)
Author information
Authors and Affiliations
Rights and permissions
Copyright information
© 2017 Springer Japan
About this chapter
Cite this chapter
Yamamoto, S. (2017). Chemistry of Diffuse Clouds. In: Introduction to Astrochemistry. Astronomy and Astrophysics Library. Springer, Tokyo. https://doi.org/10.1007/978-4-431-54171-4_4
Download citation
DOI: https://doi.org/10.1007/978-4-431-54171-4_4
Published:
Publisher Name: Springer, Tokyo
Print ISBN: 978-4-431-54170-7
Online ISBN: 978-4-431-54171-4
eBook Packages: Physics and AstronomyPhysics and Astronomy (R0)