Display Full Text | Download Full Text
8.33 MB PDF file

Degree

Master of Science (MS), Bowling Green State University, Physics, 2011.

Abstract

We have searched for Long Period Variable (LPV) stars in the metal-rich cluster NGC 6388 using time series photometry in the V and I bandpasses. A CMD was created, which displays the tilted red HB at V = 17.5 mag. and the unusual prominent blue HB at V = 17 to 18 mag. Time-series photometry and periods have been presented for 63 variable stars, of which 30 are newly discovered variables. Of the known variables nine are LPVs. We are the first to present light curves for these stars and to classify their variability types. We find 3 LPVs as Mira, 6 as Semi-regulars (SR) and 1 as Irregular (Irr.), 18 are RR Lyrae, of which we present complementary time series and period for 14 of these stars, and 7 are Population II Cepheids, of which we present complementary time series and period for 4 of them. The newly discovered variables are all suspected LPV stars and we classified them, using time series photometry and periods, as Mira for 1 star, SR for 15 stars, Irr for 7 stars, Suspected Variables for 7 stars, out of which there are 3 very bright stars that could have overexposed the CCD, with no definite borderline between the SR and Irr stars. Once classified we used probable distance for the cluster center and location on the CMD to establish possible membership, which left us with 63 possible cluster members, but the crowdedness of the cluster and the fact that the cluster is located near the bulge of the Milky Way prevents us from establishing a better certainty for its membership.

Subject Headings

Astronomy; Astrophysics; Physics

Keywords

NGC 6388; globular cluster; metal-rich; variable stars; long period variable stars; mira; ISIS; DAOPHOT; ALLSTAR; ALLFRAME; DAOMASTER; irregular; semi-regular; pulsation

Committee / Advisors

Dr. Andrew C. Layden (Advisor)
Dr. John Laird (Committee Member)
Dr. Dale W. Smith (Committee Member)

Pages

171p.

Document number: bgsu1308577583
Permalink: http://rave.ohiolink.edu/etdc/view?acc_num=bgsu1308577583

This ETD has been downloaded 59 times (through March 2013)