Photometric study of open star clusters in II quadrant: Teutsch 1 and Riddle 4

作者：Bisht D^*; Yadav R K S; Durgapal A K

来源：New Astronomy, 2016, 42: 66-77.

DOI：10.1016/j.newast.2015.06.005

• Star cluster - individual: Teutsch 1 and Riddle 4-star: interstellar extinctions
• Mass function
• Dynamical state
• Galaxy: structure

We present the broad band UBVI CCD photometry in the region of two open star clusters Teutsch 1 and Riddle 4 located in the second Galactic quadrant. The optical CCD data for these clusters are obtained for the first time. Radii of the clusters are estimated as 3'.5 for both the clusters. Using two color (U - B) versus (B - V) diagram we determined the reddening as E(B - V) = 0.40 +/- 0.05 mag for Teutsch 1 and 1.10 +/- 0.05 mag for Riddle 4. Using 2MASSJHK and optical data, we estimated E (J - K) = 0.24 +/- 0.05 mag and E (V - K) = 1.40 +/- 0.05 mag for Teutsch 1 and E(J - K) = 0.47 +/- 0.06 mag and E(V - K) = 2.80 +/- 0.06 mag for Riddle 4. Colorexcess ratio indicates normal interstellar extinction law in the direction of both the clusters. We estimated distance as 4.3 +/- 0.5 Kpc for Teutsch 1 and 2.8 +/- 0.2 Kpc for Riddle 4 by comparing the color-magnitude diagram of the clusters with theoretical isochrones. The age of the clusters has been estimated as 200 +/- 20 Myr for Teutsch 1 and 40 +/- 10 Myr for Riddle 4 using the stellar isochrones of metallicity Z = 0.02. The Mass function slope has been derived 1.89 +/- 0.43 and 1.41 +/- 0.70 for Teutsch 1 and Riddle 4 respectively. Our analysis indicates that both the clusters are dynamically relaxed. A slight bend of Galactic disc towards the southern latitude is found in the longitude range I = 130-180 degrees.

• 出版日期2016-1