Program: GN-2016A-Q-92

The object MWC 819 belongs to the group of unclassified B[e] stars, because its evolutionary state is still unclear. It was suggested to be either a B[e] supergiant or a proto-planetary nebula, due to the uncertain distance. To resolve this ambiguity between a high- and intermediate-mass object, the molecular content in the circumstellar environment could provide the key to classification. While the environments of evolved high-mass stars display oxygen-based molecules, those of intermediate-mass stars are dominated by carbon-based molecules. Recent medium-resolution observations of MWC 819 in the L-band revealed a faint emission structure that could be tentatively identified as emission from CS. However, confirmation of this identification is still pending. We propose to obtain a high-resolution L-band spectrum in the region of the theoretically predicted CS band emission. Definite detection of this molecule will allow us to unambiguously classify MWC 819 as proto-planetary nebula.