The Unusual Circumstellar Environment of the Evolved Star, U Equ
Session 35 -- ISM: Abundances and Dust
Display presentation, Wednesday, June 14, 1995, 9:20am - 6:30pm

## [35.15] The Unusual Circumstellar Environment of the Evolved Star, U Equ

C. Barnbaum (NRAO), M. Omont (IAP), M. Morris (UCLA)

In the course of a spectrosopic survey to identify cold IRAS stars, we discovered that the evolved star, U Equ, has a very peculiar optical spectrum that indicates an unusual circumstellar environment. The moderate resolution (3.5 \AA\ pixel$^{-1}$) spectrum has deep, yet unusually thin, molecular absoprtion features that must arise in cold gas at a large distance from the star. The optical spectrum also has striking molecular emission lines (AlO, VO, TiO) most likely due to a fluorescence mechanism. The LRS spectrum reveals silcate absorption whereas other stars with similar 12/25 $\mu$m colors have the silicate band in emission. H$_2$O and OH masers have been detected with a complex and varible velocity pattern. We suggest that the star is of a warm spectral type, G to early K, and that it has an edge-on dusty disk with an extended and possibly non-spherical circumstellar shell. We present optical spectra, and J- and K-band images and photometry.