A Caltech Library Service

Far-infrared dust opacity and visible extinction

Cambrésy, L. and Boulanger, F. and Lagache, G. and Stepnik, B. (2002) Far-infrared dust opacity and visible extinction. EAS Publications Series, 4 . p. 291. ISSN 1633-4760. doi:10.1051/eas:2002090.

Full text is not posted in this repository. Consult Related URLs below.

Use this Persistent URL to link to this item:


We present an extinction map of the Polaris molecular cirrus cloud derived from star counts and compare it with the Schlegel et al. [13] extinction map derived from the far-infrared dust opacity. We find that, within the Polaris cloud, the Schlegel et al. [13] AV values are, on average, a factor 2 higher than the star count values. We propose that this discrepancy results from a difference in τ_(FIR)/A_V between the diffuse atomic medium and the Polaris cloud. We use the difference in spectral energy distribution, warm for the diffuse atomic medium, cold for the Polaris cloud, to separate their respective contribution to the line of sight integrated infrared emission and find that the τ_(FIR)/A_V of cold dust in Polaris is on average 4 times higher than the Schlegel et al. [13] value for dust in atomic cirrus. This change in dust property could be interpreted by a growth of fluffy particles within low opacity molecular cirrus clouds such as Polaris. Our work suggests that variations in dust emissivity must be taken into account to estimate AV from dust emission wherever cold infrared emission is present (i.e. molecular clouds).

Item Type:Article
Related URLs:
URLURL TypeDescription
Additional Information:© 2002 EAS, EDP Sciences. Published online 25 September 2002.
Group:Infrared Processing and Analysis Center (IPAC)
Record Number:CaltechAUTHORS:20180208-161233880
Persistent URL:
Official Citation:Far-infrared dust opacity and visible extinction L. Cambrésy, F. Boulanger, G. Lagache and B. Stepnik EAS Publications Series, 4 (2002) 291 DOI:
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:84749
Deposited By: Tony Diaz
Deposited On:09 Feb 2018 00:25
Last Modified:15 Nov 2021 20:22

Repository Staff Only: item control page