The sudden appearance of CO emission in LHA 115-S 65

Abstract

Molecular emission has been detected in several Magellanic Cloud B[e] supergiants. In this Letter, we report on the detection of CO band head emission in the B[e] supergiant LHA 115-S 65, and present a K-band near-infrared spectrum obtained with the Spectrograph for INtegral Field Observation in the Near-Infrared (SINFONI; R=4500) on the ESO VLT UT4 telescope. The observed molecular band head emission in S 65 is quite surprising in light of a previous non-detection by McGregor et al. 1989, as well as a high resolution (R=50000) Gemini/Phoenix spectrum of this star taken nine months earlier showing no emission. Based on analysis of the optical spectrum by Kraus et al. 2010, we suspect that the sudden appearance of molecular emission could be due to density build up in an outflowing viscous disk, as seen for Be stars. This new discovery, combined with variability in two other similar evolved massive stars, indicates an evolutionary link between B[e] supergiants and LBVs.

Letter accepted for publication in MNRAS. 5 pages, 2 figures, 1 table

References in corpus (7)

• Spitzer SAGE Infrared Photometry of Massive Stars in the Large Magellanic Cloud
• Spitzer SAGE-SMC Infrared Photometry of Massive Stars in the Small Magellanic Cloud
• The pre- versus post-main sequence evolutionary phase of B[e] stars: Constraints from 13CO band emission
• A new observational tracer for high-density disc-like structures around B[e] supergiants
• Neutral material around the B[e] supergiant star LHA 115-S 65: An outflowing disk or a detached Keplerian rotating disk?
• The ${}^{13}$Carbon footprint of B[e] supergiants
• On the hydrogen neutral outflowing disks of B[e] supergiants

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• Molecular emission from GG Car's circumbinary disk
• The circumstellar environment and evolutionary state of the supergiant B[e] star Wd1-9
• Discovery of the first B[e] supergiants in M 31
• Inhomogeneous molecular ring around the B[e] supergiant LHA 120-S 73
• Dusty Blue Supergiants: News from High-Angular Resolution Observations
• Discovery of SiO band emission from Galactic B[e] supergiants
• Evidence of an evolved nature of MWC 349A
• A new outburst of the yellow hypergiant star Rho Cas
• Dense Molecular Environments of B[e] Supergiants and Yellow Hypergiants
• Resolving the circumstellar environment of the Galactic B[e] supergiant star MWC 137. II. Nebular kinematics and stellar variability
• Intriguing detection of ${}^{12}$CO molecular emission in a classical Be star