We studied the circumstellar environment of the B[e] star HD 45677 through the analysis of the emission lines from ionized metals. 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 km s-1. We have demonstrated that emission lines have narrow and broad components. We used the statistical approach of the self absorption curve method (SAC) to derive physical parameters of the line emitting regions. We obtained a Boltzmann-type population law whose excitation temperature is 3 900-600+900 K and 3 150-300+350 K for the narrow component lower and upper levels respectively in 1999. A value of 3 400-300+350 K is obtained for the broad component upper levels. In the framework of a very simplified geometrical model, we argue that the permitted line narrow components are principally emitted by an optically thin disk seen nearly pole-on, in a region whose minimum radius is estimated to be 4 1012 cm, while the broad ones are formed in a disk-linked wind. The forbidden lines are found to be formed in the outer regions, where the rotational velocity is lower, with higher excitation temperatures of 10 500 ± 1 000 K and 8 000 ± 1 500 K for the narrow and broad component upper levels respectively at the same epoch.

Circumstellar Environment of the B[e] Star HD 45677 (FS CMa)

ROSSI, Corinne;
2006

Abstract

We studied the circumstellar environment of the B[e] star HD 45677 through the analysis of the emission lines from ionized metals. 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 km s-1. We have demonstrated that emission lines have narrow and broad components. We used the statistical approach of the self absorption curve method (SAC) to derive physical parameters of the line emitting regions. We obtained a Boltzmann-type population law whose excitation temperature is 3 900-600+900 K and 3 150-300+350 K for the narrow component lower and upper levels respectively in 1999. A value of 3 400-300+350 K is obtained for the broad component upper levels. In the framework of a very simplified geometrical model, we argue that the permitted line narrow components are principally emitted by an optically thin disk seen nearly pole-on, in a region whose minimum radius is estimated to be 4 1012 cm, while the broad ones are formed in a disk-linked wind. The forbidden lines are found to be formed in the outer regions, where the rotational velocity is lower, with higher excitation temperatures of 10 500 ± 1 000 K and 8 000 ± 1 500 K for the narrow and broad component upper levels respectively at the same epoch.
ASP Conference Series,
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Utilizza questo identificativo per citare o creare un link a questo documento: http://hdl.handle.net/11573/214452
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