Optical Spectroscopy of the Unusual Emission-Line Object MWC 560
Abstract
MWC 560, classified Beq in the original Mt. Wilson survey but noted as type M4ep by Sanduleak and Stephenson (Ap.J. 185, 899), underwent an outburst in 1990. Between Feb.-Apr. 1990 the star showed dramatic UV spectral variability, indicating the ejection of a thick shell (Michalitsianos et al., Ap.J. 371, 761). We have monitored the optical spectrum of MWC 560 during 1990-92 at Ritter Observatory using a fiber-coupled spectrograph and CCD, in coordination with IUE. Very significant spectral changes took place between the 90/91 and 91/92 observing seasons. Compared with 90/91, the data from a year later show: a broader and more blueshifted (-2200 km/s) absorption component of the strong Hα emission line; weaker Fe II, O I, and He I emission lines; much weaker D-line absorption. In the 8000-9000 Angstroms region, the Ca II infrared triplet lines are strong, narrow emission features, superimposed on the continuum of an M5 star; TiO bandheads appear stronger in 91/92 than a year earlier. The visible/red spectrum of MWC 560 appears to have been dominated by optically thick shell features in late-1990/early-1991. By November 1991, the shell signatures have weakened, and a variable high-velocity wind profile is evident at Hα . This research was partially supported by grants from NASA.
- Publication:
-
American Astronomical Society Meeting Abstracts #180
- Pub Date:
- May 1992
- Bibcode:
- 1992AAS...180.4413B