AAS 197, January 2001
Session 46. Variable Stars
Display, Tuesday, January 9, 2001, 9:30am-7:00pm, Exhibit Hall

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[46.15] The DIRECT Project: An Unique Sample of Bright Long-period and Irregular Variables.

K. Z. Stanek, L. M. Macri, D. D. Sasselov (Harvard-Smithsonian Center for Astrophysics), J. Kaluzny (Copernicus Astronomical Center)

The DIRECT project obtained about 170 nights on the FLWO 1.2-meter telescope and 35 nights on the MDM 1.3-meter telescope between 1996 and 1999 to search for detached eclipsing binaries and Cepheids in the M31 and the M33 galaxies. This was the first step in an ongoing program to improve the direct distance estimate to these two important galaxies in the cosmological distance ladder.

The extensive photometry we have obtained as part of the DIRECT project over the past four years allows us to serendipitously find large number of bright (mV > 22 ~ MV > -2.5), long-period and irregular variables in these two galaxies. We present the properties of over 100 such variables found in the field M33C. This field was imaged during 64 nights on three consecutive observing seasons (1996-1998). We obtained a total of 270\times900s V-band, 80\times600s I-band, and 35\times1200s B-band exposures for this field.

Our program represents the first large-scale systematic CCD search and characterization of the brightest (MV > -6) variables, since similar objects in the Magellanic Clouds are too bright to have been observed by microlensing searches. We discuss possible applications of this data set for studies of massive stars and for work on the extragalactic distance scale.

This work was supported by NASA through Hubble Fellowship grant HF-01124.01-A from the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS5-26555.

If you would like more information about this abstract, please follow the link to http://cfa-www.harvard.edu/~kstanek/DIRECT/. This link was provided by the author. When you follow it, you will leave the Web site for this meeting; to return, you should use the Back comand on your browser.

The author(s) of this abstract have provided an email address for comments about the abstract: kstanek@cfa.harvard.edu

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