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Session 41 - T Tauri Stars & Protostellar Regions.
Display session, Wednesday, June 11
South Main Hall,

[41.10] Photometric Distances to Dark Clouds and Small Bok Globules: CB24

D. Peterson, D. Clemens (Boston U.)

Bok globules are small molecular clouds which are likely sites for star formation. However, finding distances to small Bok globules is difficult. A new method of distance determination has been developed which is based on broad band photometric data acquisition and analysis. Using color-color diagrams to estimate the spectral types and extinctions of M-dwarf stars which occur in front of and behind the molecular clouds, the distances to the clouds can be bracketed to a higher degree of precision than previously possible.

In this poster, this new method is applied to CB24, a small Bok globule from the catalog of Clemens and Barvainis (ApJS 1988). Observations were conducted at the 1-m Mt. Laguna telescope operated by San Diego State University and reduced using IRAF. A (V-I) vs. (B-V) plot of the stars in the 13.7^\prime x 13.7^\prime field has been analyzed, and a select group of thirty-two candidate M-dwarf stars identified. Their colors were de-reddened back to a zero-extinction line whose position was established based on published data for nearby M-dwarfs. A standard extinction law was used to perform the de-reddening and a future effort will explore how changes in the reddening law affect the inferred cloud distance.

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