Abstract
The classification of numerous Galactic B[e] stars is hampered by uncertain or unknown stellar parameters. In addition, Herbig B[e] stars and B[e] supergiants, both surrounded by dusty disks, show many spectroscopic similarities. We use the ^{12}C/^{13}C ratio, which drops drastically during stellar evolution, and show that the appearance of ^{13}CO band emission is an unambiguous proof for a supergiant nature.
