SCYON Abstract

Received on: 14 07 2023

A deep optical survey of young stars in the Carina Nebula. I. - UBVRI photometric data and fundamental parameters

Authors:H. Hur 1, B. Lim 2,3, M.-Y. Chu 3
Affiliations:(1) The Young Astronauts Korea, Gangnam-gu, Seoul, Republic of Korea; (2) Department of Earth Science Education, Kongju National University, Gongju-si, Chungcheongnam-do, Republic of Korea; (3) Korea Astronomy and Space Science Institute, Yuseong-gu, Daejeon, Republic of Korea
Accepted by: Journal of the Korean Astronomical Society

We present the deep homogeneous $UBVRI$ photometric data of 135,071 stars down to $V\sim23$ mag and $I \sim 22$ mag toward the Carina Nebula. These stars are cross-matched with those from the previous surveys in the X-ray, near-infrared, and mid-infrared wavelengths as well as the Gaia Early Data Release 3 (EDR3). This master catalog allows us to select reliable members and determine the fundamental parameters distance, size, stellar density of stellar clusters in this star-forming region. We revisit the reddening toward the nebula using the optical and the near-infrared colors of early-type stars. The foreground reddening [E(B-V)$_{fg}$] is determined to be 0.35$\pm$0.02, and it seems to follow the standard reddening law. On the other hand, the total-to-selective extinction ratio of the intracluster medium (R$_{V,cl}$) decreases from the central region (Trumpler 14 and 16, R$_{V,cl}$ $\sim$ 4.5) to the northern region (Trumpler 15, R$_{V,cl}$ $\sim$ 3.4). It implies that the central region is more dusty than the northern region. We find that the distance modulus of the Carina Nebula to be 11.9$\pm$0.3 mag (d = 2.4$\pm$0.35 kpc) using a zero-age main-sequence fitting method, which is in good agreement with that derived from the Gaia EDR3 parallaxes. We also present the catalog of 3,331 pre-main-sequence (PMS) members and 14,974 PMS candidates down to V $\sim$ 22 mag based on spectrophotometric properties of young stars at infrared, optical, and X-ray wavelengths. From the spatial distribution of PMS members and PMS candidates, we confirm that the member selection is very reliable down to faint stars. Our data will have a legacy value for follow-up studies with different scientific purposes.

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