2006ApJ...637..774C


C.D.S. - SIMBAD4 rel 1.7 - 2019.12.07CET22:35:16

2006ApJ...637..774C - Astrophys. J., 637, 774-785 (2006/February-1)

Pixie dust: the silicate features in the diffuse interstellar medium.

CHIAR J.E. and TIELENS A.G.G.M.

Abstract (from CDS):

We have analyzed the 9.7 and ``18'' µm interstellar silicate absorption features along the line of sight toward four heavily extincted galactic WC-type Wolf-Rayet (WR) stars. We construct two interstellar extinction curves from 1.25 to 25 µm using near-IR extinction measurements from the literature, along with the silicate profiles of WR 98a (representing the local ISM) and GCS 3 (representing the Galactic center). We have investigated the mineralogy of the interstellar silicates by comparing extinction profiles for amorphous silicates with olivine and pyroxene stoichiometry to the 9.7 and ``18'' µm absorption features in the WR 98a spectrum. In this analysis, we have considered solid and porous spheres and a continuous distribution of ellipsoids. While it is not possible to simultaneously provide a perfect match to both profiles, we find that the best match requires a mixture of these two types of compounds. We also consider iron oxides, aluminosilicates, and silicate carbide (SiC) as grain components. Iron oxides cannot be accommodated in the observed spectrum, while the amount of Si in SiC is limited to <4%. Finally, we discuss the cosmic elemental abundance constraints on the silicate mineralogy, grain shape, and porosity.

Abstract Copyright:

Journal keyword(s): ISM: Dust, Extinction - Infrared: ISM - ISM: Abundances - ISM: Lines and Bands - ISM: Molecules

Simbad objects: 13

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Number of rows : 13

N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2020
#notes
1 OH 127.8 -0.0 OH* 01 33 51.21 +62 26 53.2           M9III 170 0
2 NAME Trapezium Cluster As* 05 35 16.5 -05 23 14           ~ 1436 1
3 WR 98a WR* 17 41 13.0431655551 -30 32 30.425152324   18.40   15.20 13.82 WC8/9 87 1
4 NAME Gal Center reg 17 45 40.04 -29 00 28.1           ~ 11077 0
5 NAME Quintuplet Cluster OpC 17 46 13.9 -28 49 48           ~ 426 0
6 LHO 75 WR* 17 46 14.11 -28 49 36.7           WC9?d 20 0
7 LHO 102 WR* 17 46 14.30 -28 49 31.5           WC9?d 20 0
8 WR 102dc WR* 17 46 14.69 -28 49 40.7           WC9d+OB 50 0
9 GCS 3 IR 17 46 15 -28 49.6           ~ 49 0
10 MR 80 WR* 18 02 04.1238716757 -23 37 42.144766363   14.85       WC9 204 2
11 WR 112 WR* 18 16 33.49 -18 58 42.3   20.7 17.7     WC8+O6/7III/V 116 0
12 RAFGL 2179 WR* 18 31 42.2117071870 -09 59 16.687501795   25.0 22.0     WC9 83 0
13 * mu. Cep s*r 21 43 30.4610574 +58 46 48.160181 8.85 6.43 4.08 1.98 0.22 M2-Ia 616 1

    Equat.    Gal    SGal    Ecl

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2019.12.07-22:35:16

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