2008/09/10 by Himali Joshi, Brijesh Kumar, K. P. Singh +4
Physics and Astronomy · #Astrophysical Phenomena and Observations #Astrophysics and Star Formation Studies #Stellar, planetary, and galactic studies #astro-ph
paper · pdf · doi:10.1111/j.1365-2966.2008.13936.x
23 pages, 23 figures, 13 tables; Accepted for publication in MNRAS
arxiv created 2008/09/10 · openalex publication_date 2008/11/06 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/29
Using new UBVRI Hα CCD photometric observations and the archival infrared and X-ray data, we have carried out a multiwavelength study of a Perseus arm young open star cluster NGC 7419. An age of 22.5 ± 3.0 Myr and a distance of 3230+330−430 pc are derived for the cluster. Our photometric data indicate a higher value of colour excess ratio E(U−B)/E(B−V) than the normal one. There is an evidence for mass segregation in this dynamically relaxed cluster and in the range 1.4–8.6 M⊙, the mass function slope is in agreement with the Salpeter value. Excess emissions in near-infrared and Hα support the existence of a young (≤2 Myr) stellar population of Herbig Ae/Be stars (≥3.0 M⊙) indicating a second episode of star formation in the cluster region. Using XMM–Newton observations, we found several X-ray sources in the cluster region but none of the Herbig Ae/Be stars is detected in X-rays. We compare the distribution of upper limits for Herbig Ae/Be stars with the X-ray distribution functions of the T Tauri and the Herbig Ae/Be stars from previous studies, and found that the X-ray emission level of these Herbig Ae/Be stars is not more than LX∼ 5.2 × 1030erg s−1, which is not significantly higher than for the T Tauri stars. Therefore, X-ray emission from Herbig Ae/Be stars could be the result of either unresolved companion stars or a process similar to T Tauri stars. We report an extended X-ray emission from the cluster region NGC 7419, with a total X-ray luminosity estimate of ∼1.8 × 1031erg s−1arcmin−2. If the extended emission is due to unresolved emission from the point sources then we estimate ∼288 T Tauri stars in the cluster region each having X-ray luminosity ∼1.0 × 1030erg s−1. Investigation of dust attenuation and12CO emission map of a square degree region around the cluster indicates the presence of a foreground dust cloud which is most likely associated with the local arm star-forming region (Sh2−154). This cloud harbours uniformly distributed pre-main-sequence stars (0.1–2.0 M⊙), with no obvious trend of their distribution with either (H−K) excess or AV. This suggests that the star formation in this cloud depend mostly upon the primordial fragmentation.