Estimating Age of The Open Cluster M34 Using Turn - Off Point of The Stars on The Main Sequenc

Abstract

In this work I observed the open cluster M34 using 16 inch reflecting telescope to estimate the age of the cluster using turn–off point of a star from the main sequence stars on the B – V color magnitude diagram. This can be done by plotting the stars in a so-called HertzsprungRussell (HR) diagram, revealing the nature of the stars. Since the hot and bright (high-mass) stars have much shorter lives than the colder and fainter (low-mass) stars, we can find the cluster age by finding the hottest stars still remaining in the cluster (the turn off point). In order to obtain images of stars at different wavelengths for photometric study. one might use images taken through the B- and V-band filters to determine B-V color of the stars. To avoid a worse seeing or the high brightness of the saturating stars in the cluster one can limit the field of view of the telescope so that only part of the cluster can be imaged at once, so, I used four parts of the image at lower left, lower right, upper left, and upper right. On the other hand there are many faint stars in our cluster. So, several images will be need in each B, and V- filters, at different exposure time. I used 30 s and 300 s. The long exposure for measuring the fainter stars, and the short exposure for measuring the bright stars, and it is important for our aim of this work that the bright stars are included in the selection, to determine the turn–off point of the cluster. By using aperture photometry on 232 stars, the age of the cluster has been estimated to be between 100-260 Myr. To estimate the seeing, ten stars have been examined to give the value of 3.03 arcsec in B-filter and 2.7 arcsec in V-filter.