AAS 205th Meeting, 9-13 January 2005
Session 9 NURO Asteroids and Stars
Poster, Monday, January 10, 2005, 9:20am-6:30pm, Exhibit Hall

## [9.02] Secular'' and Periodic Components in the Optical Variability of MWC349

J. Stortz (Contra Costa Coll. and Maria Mitchell Obs.), V. Strelnitski (Maria Mitchell Obs.)

MWC349, a peculiar emission-line star, is the only known source of hydrogen maser and laser emission, which presumably arises in an edge-on circumstellar disk. In order to study the declared but so far poorly known optical variability of this object, we have monitored it in B, V, R and I for seven years (1997-2004) using the 31-in reflector with the NURO CCD at Lowell Observatory. Our photometry suggests at least two components of variation, possibly caused by different mechanisms: (1) a secular'' decline of 0.05 mag per year in B and V, 0.04 mag/yr in I and 0.03 mag/yr in R; and (2) quasi-periodic oscillations, with a period of 3 +/- 0.3 years, and variable (max minus min) amplitudes of 0.1-0.2 mag. The changes of the brightness are accompanied by significant changes of the color indices. In particular, the light curve in the R band (comprising the H\alpha line, which is extremely strong in MWC349A), demonstrates peculiarities that suggest substantial differences in the mechanisms of the line and continuum formation. We highly appreciate the help in observations on the part of NURO and Ed Anderson, in particular. This project was supported by the NSF/REU grant AST-0354056 and the Nantucket Maria Mitchell Association.