AAS 206th Meeting, 29 May - 2 June 2005
Session 8 Circumstellar Shells and Disks
Poster, Monday, 9:20am-6:30pm, Tuesday, 10:00am-7:00pm, May 30, 2005, Ballroom A

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[8.03] Circumstellar Disks in the IR: Identification of New Systems and Evidence of Complex Density Structures

J.P. Wisniewski (U. Toledo), A. F. Kowalski (U. Chicago), K.S. Bjorkman, J.E. Bjorkman (U. Toledo)

We use 0.8-2.4 micron spectroscopy to explore the circumstellar environments of a small sample of stars in the Galactic clusters NGC 2186 and NGC 2439 that were previously identified as excess H\alpha emitters from 2-color diagram photometric observations. We detect both H~I and various metal emission lines in ~60% of our sample, indicating that these objects do have circumstellar disks. Analysis of line profile morphologies suggests the presence of a one-armed spiral density wave in at least one circumstellar disk system. Furthermore, we find the V/R ratios of the H~I Brackett emission lines are opposite those of the Fe~II emission lines in this particular system, implying that our observations may be used to probe the structure of the spiral density wave as a function of disk radius.

We also present initial results of near contemporaneous optical and 0.8-2.4 micron spectroscopic observations of several known Galactic classical Be stars. Theoretical line profile calculations (Waters & Marlborough 1992) predict scenarios in which one should observe the V/R ratios of the optical H\alpha and IR H lines to be oppositely oriented; we believe we have found conclusive evidence of this in our observations of Zeta Tau. We discuss our efforts to use these line strengths and profiles to constrain the density structure and fundamental parameters of these circumstellar disks.

Observations were obtained using the SpeX instrument at the NASA IRTF on Mauna Kea, Hawaii. This work has been supported in part by grants from the NASA LTSA, NASA GSRP, Sigma Xi GIAR, and NSF REU programs. KSB is a Cottrell Scholar of the Research Corporation and gratefully acknowledges their support.

The author(s) of this abstract have provided an email address for comments about the abstract: jwisnie@physics.utoledo.edu

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© 2005. The American Astronomical Soceity.