Hyeonoh Hur

SEJONG OPEN CLUSTER SURVEY (SOS). 0. TARGET SELECTION AND DATA ANALYSIS

Star clusters are superb astrophysical laboratories containing cospatial and coeval samples of stars with similar chemical composition. We initiate the Sejong Open cluster Survey (SOS) - a project dedicated to providing homogeneous photometry of a large number of open clusters in the SAAO Johnson-Cousin’ UBVI system. To achieve our main goal, we pay much attention to the observation of standard stars in order to reproduce the SAAO standard system. Many of our targets are relatively small sparse clusters that escaped previous observations. As clusters are considered building blocks of the Galactic disk, their physical properties such as the initial mass function, the pattern of mass segregation, etc. give valuable information on the formation and evolution of the Galactic disk. The spatial distribution of young open clusters will be used to revise the local spiral arm structure of the Galaxy. In addition, the homogeneous data can also be used to test stellar evolutionary theory, especially concerning rare massive stars. In this paper we present the target selection criteria, the observational strategy for accurate photometry, and the adopted calibrations for data analysis such as color-color relations, zero-age main sequence relations, Sp-Mv relations, Sp ? T eff relations, Sp ? color relations, and T eff ? BC relations. Finally we provide some data analysis such as the determination of the reddening law, the membership selection criteria, and distance determination.

Reddening, distance, and stellar content of the young open cluster Westerlund 2

We present deep

The Sejong Open Cluster Survey (SOS). IV. the Young Open Clusters NGC 1624 and NGC 1931

UBVI_C

[ERRATUM] "SEJONG OPEN CLUSTER SURVEY (SOS). 0. TARGET SELECTION AND DATA ANALYSIS"

photometric data of the young open cluster Westerlund 2. An abnormal reddening law of

DISTANCE AND THE INITIAL MASS FUNCTION OF YOUNG OPEN CLUSTERS IN THE η CARINA NEBULA: Tr 14 AND Tr 16

R_{V,cl}=4.14\pm0.08

The starburst cluster westerlund 1: The initial mass function and mass segregation

was found for the highly reddened early-type members (

[Fe II] 1.64 μm Features of Jets and Outflows from Young Stellar Objects in the Carina Nebula

E(B-V)\geq 1.45

The Initial Mass Function of Young Open Clusters in the Galaxy: A Preliminary Result

), whereas a fairly normal reddening law of

A Photometric Study of the Young Open Cluster IC 1805

R_{V,fg}=3.33\pm0.03

The CTIO 4m UBVI & Hα photometry and spatial variation of the reddening law in the η Carina nebula

was confirmed for the foreground early-type stars (