An investigation of poorly studied open cluster NGC 4337 using multi-color photometric and Gaia DR2 astrometric data

Abstract

We present a comprehensive analysis (photometric and kinematical) of poorly studied open cluster NGC 4337 using 2MASS, WISE, APASS, and Gaia~DR2 database. By determining the membership probabilities of stars, we identified 624 most probable members with membership probability higher than $50\%$ by using proper motion and parallax data taken from Gaia~DR2. The mean proper motion of the cluster is obtained as $\hat{I}{¼}_x=-8.83\pm 0.01$ and $\hat{I}{¼}_y=1.49\pm 0.006$ mas yr${}^{-1}$. We find the normal interstellar extinction towards the cluster region. The radial distribution of members provides a cluster radius of 7.75 arcmin (5.63 pc). The estimated age of $1600\pm 180$ Myr indicates that NGC 4337 is an old open cluster with a bunch of red giant stars. The overall mass function slope for main-sequence stars is found as $1.46\pm 0.18$ within the mass range 0.75$-$2.0 $M_{\odot }$, which is in fair agreement with Salpeter's value (x=1.35) within uncertainty. The present study demonstrates that NGC 4337 is a dynamically relaxed open cluster. Using the Galactic potential model, Galactic orbits are obtained for NGC 4337. We found that this object follows a circular path around the Galactic center. Under the kinematical analysis, we compute the apex coordinates $(A,D)$ by using two methods: (i) the classical convergent point method and (ii) the AD-diagram method. The obtained coordinates are: $(A_{conv},D_{conv})$ = (96${}^{\text{o}}$.27 $\pm$ 0${}^{\text{o}}$.10, 13${}^{\text{o}}$.14 $\pm$ 0${}^{\text{o}}$.27) $\&$ $(A_{\circ },D_{\circ })$ = (100${}^{\text{o}}$.282 $\pm$ 0${}^{\text{o}}$.10, 9${}^{\text{o}}$.577 $\pm$ 0${}^{\text{o}}$.323) respectively. We also computed the Velocity Ellipsoid Parameters (VEPs), matrix elements ($\hat{I}{¼}_{ij}$), direction cosines ($l_j$, $m_j$, $n_j$) and the Galactic longitude of the vertex ($l_2$).

24 pages, 16 figures and 4 table. The article has been accepted for publication in AJ