Publication Date:
2014-07-14
Description:
We present a UBVI and Hα photometric study of the young open cluster NGC 1893 in the H ii region W8 (IC 410 or Sh 2-236). A total of 65 early-type members are selected from photometric diagrams. A mean reddening of the stars is 〈 E ( B – V )〉 = 0.563 ± 0.083 mag. The published photometric data in the near- and mid-infrared passbands are used to test the reddening law towards the cluster, and we confirm that the reddening law is normal ( R V = 3.1). Zero-age main-sequence fitting gives a distance modulus of V 0 – M V = 12.7 ± 0.2 mag, equivalent to 3.5 ± 0.3 kpc. From Hα photometry, 125 Hα emission stars and candidates are identified as pre-main-sequence (PMS). The lists of young stellar objects and X-ray sources published by previous studies allow us to select a large number of PMS members down to 1 M . Isochrone fitting in the Hertzsprung–Russell diagram gives a turn-off age of 1.5 Myr and the median age of 1.9 Myr from the PMS members with a spread of ~5 Myr. We derive the initial mass function (IMF) for stars with mass larger than 1 M . The slope of the IMF ( = –1.3 ± 0.1) is well consistent with the Salpeter/Kroupa IMF. A total mass of the cluster appears to be in excess of 1300 M . Finally, we estimate the mass accretion rate of 82 PMS members in the mass range of 0.6–5 M .
Print ISSN:
0035-8711
Electronic ISSN:
1365-2966
Topics:
Physics
