Abstract Details
| Name: prasanta nayak Affiliation: IIA, Bengaluru Conference ID: ASI2019_304 Title : UVIT-HST-GAIA study of star cluster KRON 3 in the Small Magellanic Cloud: A cluster with a large spread in metallicity Authors and Co-Authors : Prasanta. K. Nayak, A. Subramaniam, S. Subramanian, S. Sahu, C. Mondal, Maria-Rosa L. Cioni, C. Bell Abstract Type : Oral Abstract Category : Extragalactic Astronomy Abstract : A good number of massive intermediate age (∼ a few Gyr) metal poor star clusters in the Magellanic Clouds (MCs) show extended main-sequence turn-off, that cannot be explained by photometric errors or stellar binarity. Kron 3 is one of such cluster, located in the west to the main body of the Small Magellanic Cloud (SMC). In this study, we have demonstrated the power of UVIT-HST-GAIA combination to study star clusters in the Magellanic Clouds. We take advantage of the resolution of the HST in the central region of the cluster and the coverage of GAIA for outer region, to combine with the UVIT data. We have estimated the radius of the cluster Kron 3 as 2.0 arcsec from the UVIT and GAIA data. For the first time, we report the identification of NUV bright red clump (RC) stars and the extension of RC stars over two magnitudes both in colour and magnitude axis in NUV vs NUV−optical CMD. We find that the extension of RC is an intrinsic property of the cluster. With the help of theoretical isochrones, we suggest that Kron 3 exhibits multiple stellar populations with a possible age range of 6-8 Gyr and a metallicity range of [Fe/H] = -2.0 to -1.0. We included VISTA data to cover the IR region and studied the spectral energy distribution of RC stars, which confirms the metallicity spread for RC stars. The temperature of RC stars fall in the range of 5000 to 5500 K. We recommend a spectroscopic study of RC stars can put more light into the metallicity spread present in the cluster. Variable mass loss of stars in RGB can also contribute partially to the identified extension in RC. |