Analysis of the circumstellar environment of the B[ e] star HD 45677 (FS Canis Majoris)G. Muratorio1, C. Rossi2 and M. Friedjung3
1 Laboratoire d'Astrophysique de Marseille, 2 Place le Verrier, 13248 Marseille Cedex 04, France
2 Dipartimento di Fisica, Università "La Sapienza", Piazzzale A. Moro 2 00185, Roma, Italy
3 Institut d'Astrophysique, 98 bis Boulevard Arago, 75014 Paris, France
(Received 29 April 2005 / Accepted 29 December 2005 )
Aims.We studied the circumstellar environment of the B[ e] star HD 45677 through the analysis of the emission lines from ionized metals.
Methods.We used the statistical approach of the self absorption curve method (SAC) to derive physical parameters of the line emitting region.
Results.The Fe II and Cr II double-peaked emission line structure is explained by the presence of a thin absorption component red shifted by ~3 . This absorption component can be interpreted geometricaly as being due to infalling material perpendicularly to the disk seen nearly pole-on, as indicated by the emission line structure. The Cr II and Fe II emission lines have a complex structure with two (narrow and broad) components, of 45 and 180 FWHM for the permitted lines and 25 and 100 FWHM for the forbidden ones, respectively. From our best data set of 1999, we obtained a Boltzmann-type population law whose excitation temperature is and for the narrow component lower and upper levels respectively. We obtained an excitation temperature of for the broad component upper levels. The forbidden lines are found to be formed in the outer regions with higher excitation temperatures of K and K for the narrow and broad components respectively in 1999. Our results are consistent with line formation in a rotating disk, around a young star. In the framework of a very simplified geometrical model, we argue that the narrow components are principaly emitted by an optically thin disk seen nearly pole-on, in a region whose minimum radius is estimated to be cm, while the broad ones are formed in a disk-linked wind.
Key words: line: formation -- methods: data analysis -- stars: emission-line, Be -- stars: individual: HD 45677 (FS Canis Majoris)
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