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| Paper: |
Sejong Open Cluster Survey (SOS) VIII. Dynamical State of the Open Cluster NGC 2302 |
| Volume: |
536, The Twelfth Pacific Rim Conference on Stellar Astrophysics |
| Page: |
161 |
| Authors: |
Lee, Y.; Lim, B. |
| Abstract: |
We present a photometric and kinematic study of young open cluster NGC 2302. UBVI photometric data, obtained from imaging observations with the Mont4k CCD camera attached to the Kuiper 61′′ telescope, are used to determine the fundamental parameters of this cluster. A total of 159 stars are selected as members using the Gaia astrometric data. In order to investigate the reddening toward this cluster, we analyze the (U − B, B−V) diagram. As a result, this cluster is, on average, reddened by ⟨E(B − V)⟩ = 0.24. The reddening law is probed using various color excess ratios extending to near-infrared. The total-to-selective extinction (RV) is about 2.8, which is lower than that of the general interstellar medium in the solar neighborhood (RV = 3.1). The distance to this cluster, determined from a zero-age main sequence fitting method, is about 1.15 kpc. It is also in good agreement with the distance derived from the Gaia parallax. The cluster age is estimated to be about 80 ± 20 Myr according to the Padova stellar evolution model, which takes into account stellar rotation for subsolar metallicity. The total mass derived from a photometric method is about 353 ± 68 M⊙. Assuming a virial state, one-dimensional velocity dispersion (σ1D) of stars is expected to be about 0.2 km s−1. This value is smaller than σ1D = 0.5 km s−1 obtained from the Gaia proper motion. It indicates that the cluster is in a super-virial state. Finally, its relaxation timescale is estimated to be about trelax = 50 Myr, which is comparable to the age of the cluster. Our result suggests that NGC 2302 is dynamically relaxed. |
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