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

作者：Hur Hyeonoh^*; Sung Hwankyung; Bessell Michael S

来源：Astronomical Journal, 2012, 143(2): 41.

DOI：10.1088/0004-6256/143/2/41

• open clusters and associations: individual (Trumpler 14, Trumpler 16)
• stars: luminosity function, mass function
• stars: pre-main sequence

We present new UBVIc CCD photometry of the young open clusters Trumpler 14 (Tr 14) and Trumpler 16 (Tr 16) in the eta Carina Nebula. We also identify the optical counterpart of Chandra X-ray sources and Two Micron All Sky Survey point sources. The members of the clusters were selected from the proper-motion study, spectral types, reddening characteristics, and X-ray or near-IR excess emission. An abnormal reddening law R-V,(cl) = 4.4 +/- 0.2 was obtained for the stars in the eta Carina Nebula using the 141 early-type stars with high proper-motion membership probability (P-mu %26gt;= 70%). We determined the distance to each cluster and conclude that Tr 14 and Tr 16 have practically the same distance modulus of V-0 - M-V = 12.3 +/- 0.2 mag (d = 2.9 +/- 0.3 kpc). The slope of the initial mass function was determined to be Gamma = 1.3 +/- 0.1 for Tr 14, Gamma = -1.3 +/- 0.1 for Tr 16, and Gamma = -1.4 +/- 0.1 for all members in the observed region for the stars with log m %26gt;= 0.2. We also estimated the age of the clusters to be about 1-3 Myr from the evolutionary stage of evolved stars and low-mass pre-main-sequence stars.

• 出版日期2012-2