Resolving the kinematics of the disks around Galactic B[e] supergiants

B[e] Supergiants are luminous evolved massive stars. The mass-loss during this phase creates a complex circumstellar environment with atomic, molecular, and dusty regions usually found in rings or disk-like structures. For a better comprehension of the mechanisms behind the formation of these rings, detailed knowledge about their structure and dynamics is essential. To address that, we obtained high-resolution optical and near-infrared spectra for 8 selected Galactic B[e] Supergiants, for which CO emission has been detected. Assuming Keplerian rotation for the disk, we combine the kinematics obtained from the CO bands in the near-IR with those obtained by fitting the forbidden emission [OI] $\lambda$5577, [OI] $\lambda\lambda$6300,6363, and [CaII] $\lambda\lambda$7291,7323 lines in the optical to probe the disk structure. We find that the emission originates from multiple ring structures around all B[e] Supergiants, with each one of them displaying a unique combination of rings regardless of whether the object is part of a binary system. The confirmed binaries display spectroscopic variations of their line intensities and profiles as well as photometric variability, whereas the ring structures around the single stars are stable.
Comment: 27 pages, 13 figures, 4 tables. Published in MNRAS. Minor corrections in this version: (a) adding references in the text to Fig. 6, tables A6 and A8, and footnote 5, (b) adding/modifying the acknowledgments section