| Full text | |
| Author(s): Show less - |
Seriacopi, D. B.
;
Carciofi, A. C.
;
de Amorim, T. H.
;
Magalhaes, A. M.
;
Vieira, R. G.
;
de Souza, A. Domiciano
;
Rubio, A.
;
Rubinho, M. S.
;
Bednarski, D.
;
Mota, B. C.
;
Faes, D. M.
;
Silva, A. C. F.
Total Authors: 12
|
| Document type: | Journal article |
| Source: | Monthly Notices of the Royal Astronomical Society; v. 528, n. 1, p. 19-pg., 2024-01-13. |
| Abstract | |
B[e] supergiants (sgB[e]) are rare objects whose evolutionary stage remains uncertain. Observationally, they display strong Balmer emission lines, infrared excess, and intrinsic polarization, indicating a non-spherical circumstellar envelope. We present a study of the sgB[e] RMC 82, using new spectropolarimetric data complemented by photometry from the ultraviolet (UV) to the mid-infrared. Our two-component model comprises a slow, dense equatorial wind wherein dust grains form and a fast polar wind. We applied the hdust radiative transfer code and Bayesian statistics to infer the parameters from a grid of 3240 pre-computed models. The model accurately reproduces the spectral energy distribution and polarized spectrum, but struggles to match the H alpha emission. Our results suggest a large mass-loss rate of 6.6 x 10(-6)M (R) yr(-1) sr(-1). The dense wind is confined within an opening angle of 11 degrees. The hottest dust grains are located at 277R(*) with a temperature of 870 K. The dust grains are porous, with a density of 0.051 g cm(-3). The central star was found to be significantly hotter than previous estimates (T-eff = 27 000 K). By comparing models with different components, we find that gas reprocesses a significant amount of UV radiation, shielding the dust. Ho we ver, the dust also scatters UV photons back to the inner disc, increasing its temperature and H alpha emission. We conclude that self-consistent models, that account for the gas-dust interplay in the envelope, are essential for studying sgB[e] and similar objects. (AU) | |
| FAPESP's process: | 21/01891-2 - 3-D hydrodynamic simulations coupled with radiative transfer |
| Grantee: | Tajan Henrique de Amorim |
| Support Opportunities: | Scholarships in Brazil - Doctorate (Direct) |
| FAPESP's process: | 18/04055-8 - High precision spectroscopy: from the first stars to planets |
| Grantee: | Jorge Luis Melendez Moreno |
| Support Opportunities: | Research Projects - Thematic Grants |
| FAPESP's process: | 01/12589-1 - Stars, the interstellar medium and their interrelationships |
| Grantee: | Antônio Mário Magalhães |
| Support Opportunities: | Research Projects - Thematic Grants |
| FAPESP's process: | 09/54006-4 - A computer cluster for the Astronomy Department of the University of São Paulo Institute of Astronomy, Geophysics and Atmospheric Sciences and for the Cruzeiro do Sul University Astrophysics Center |
| Grantee: | Elisabete Maria de Gouveia Dal Pino |
| Support Opportunities: | Multi-user Equipment Program |
| FAPESP's process: | 19/13354-1 - Decretion disks and outflows around fast-spinning stars |
| Grantee: | Alex Cavaliéri Carciofi |
| Support Opportunities: | Regular Research Grants |
| FAPESP's process: | 10/19694-4 - SOUTH POL: revealing the polarized Southern Sky |
| Grantee: | Antônio Mário Magalhães |
| Support Opportunities: | Regular Research Grants |