Optical and Infrared Photometric Study of Pre-Main Sequence Stars in Young Open Cluster NGC 7419 Young Open Cluster NGC 7419

Optical and Infrared Photometric Study of Pre-Main Sequence Stars in Young Open Cluster NGC 7419 Young Open Cluster NGC 7419

The embryonic stage of development of stars has been a field of astrophysics which still pose many unresolved queries. The problem is largely due to the solitary nature of embryonic stars. Even the largest optical telescopes were not able to reveal many details about such stars as they are formed deep inside molecular cloud thorough which optical wavelength cannot pass through. Forbidding distances to such stars is an added problem. However, recently, this field is slowly turning into observational science. Even though optical radiations fail to reach the destination, longer wavelength infrared (IR) radiations can penetrate through such dusty region. These infrared radiations have been known for decades. But it is only during very recent times that infrared telescopes that have very high sensitivity and resolution came in to scenario. So now the astronomers are able to observe these stellar embryos. Studies about this stage of star formation can help us to solve many questions like how the birth of a star takes place, how these stars accrete matter into it from surroundings, when will this accretion stops, why do some stars have planetary systems around them etc. Current study is an attempt to look for the presence of these embryonic stars in an open cluster using infrared data and to get more details on nature of those stellar embryos. We investigate the properties of young stars and their circumstellar disks in young open cluster NGC 7419. The pre-determined V magnitude and B magnitude of these stars are combined with infrared data from 2MASS J,H, K and 4 band WISE data. The color-color diagrams are made using these 9 bands to identify young stellar objects. The individual SED fitting is done for these identified stars and parameters like their age, mass, temperature, disk radius and disk mass are estimated. These are used to comment on the evolutionary stage of the pre-main sequence stars and their circumstellar disk. Dissertation has been divided into five chapters. Chapter 1 gives a general introduction to the work done. Literatures referred are explained in Chapter 2. Data used in the current study and methodology adopted is described in chapter 3. Current work done on the young stellar objects in cluster NGC 7419 and results obtained from the study are explained in Chapter 4 and Chapter 5 respectively.

Mukundan Vrinda

Department of Physics