EDP Sciences
Free access
Volume 393, Number 3, October III 2002
Page(s) 1073 - 1079
Section The solar system
DOI http://dx.doi.org/10.1051/0004-6361:20021029

A&A 393, 1073-1079 (2002)
DOI: 10.1051/0004-6361:20021029

Mid-infrared spectrum of the zodiacal light observed with ISOPHOT

Ch. Leinert1, P. Ábrahám1, 2, J. Acosta-Pulido3, D. Lemke1 and R. Siebenmorgen4

1  Max-Planck-Institut für Astronomie, Königstuhl 17, 69117 Heidelberg, Germany
2  Konkoly Observatory of the Hungarian Academy of Sciences, PO Box 67, 1525 Budapest, Hungary
3  Instituto de Astrofísica de Canarias, via Láctea s/n, 38200 La Laguna, Tenerife, Spain
4  European Southern Observatory, Karl-Schwarzschild-Strasse 2, 85748 Garching b. München, Germany

(Received 2 September 2001 / Accepted 11 July 2002 )

We present 29 mid-infrared spectra of the zodiacal light distributed over the sky. The observed 5.9-11.7  $\mu$m spectral shapes are well represented by blackbody radiation with colour temperatures in the range of $255\leq T\leq 300$ K. The spectra are smooth and featureless. The variation of the temperature can be explained by the geometrical distribution of dust in the inner solar system. This result indicates that although the interplanetary dust particles originate from discrete sources (comets, asteroids) the interplanetary cloud of today seems to be well mixed in terms of grain composition and size distribution.

Key words: interplanetary medium -- infrared: solar system

Offprint request: Ch. Leinert, leinert@mpia-hd.mpg.de

© ESO 2002