Photometric and Kinematic study of the open clusters SAI 44 and SAI 45

TL;DR

This study provides a comprehensive photometric and kinematic analysis of the open clusters SAI 44 and SAI 45, revealing their membership, distances, ages, dynamical states, and kinematic properties using ground-based and Gaia data.

Contribution

It offers the first detailed combined photometric and kinematic characterization of SAI 44 and SAI 45, including membership, age, distance, and dynamical analysis.

Findings

SAI 44 has 204 members; SAI 45 has 74 members.

SAI 44 is at 3670 pc; SAI 45 at 1668 pc.

SAI 45 shows an extended main-sequence turn-off.

Abstract

We carry out detailed photometric and kinematic study of the poorly studied sparse open clusters SAI 44 and SAI 45 using ground based BVR$_{c}$I$_{c}$ data supplemented by archival data from \textit{Gaia} eDR3 and Pan-STARRS. The stellar membership are determined using a statistical method based on \textit{Gaia} eDR3 kinematic data and we found 204 members in SAI 44 while only 74 members are identified in SAI 45. The average distances to SAI 44 and SAI 45 are calculated as 3670$\pm$184 and 1668$\pm$47 pc. The logarithmic age of the clusters are determined as 8.82$\pm$0.10 and 9.07$\pm$0.10 years for SAI 44 and SAI 45, respectively. The color-magnitude diagram of SAI 45 hosts an extended main-sequence turn-off (eMSTO) which may be originated through differential rotation rates of member stars. The mass function slopes are obtained as -1.75$\pm$0.72 and -2.58$\pm$3.20 in the mass rages 2.426-0.990 M$_{\odot}$ and 2.167-1.202 M$_{\odot}$ for SAI 44 and SAI 45, respectively. SAI 44 exhibit the signature of mass segregation while we found a weak evidence of the mass segregation in SAI 45 possibly due to tidal striping. The dynamical relaxation times of these clusters indicate that both the clusters are in dynamically relaxed state. Using AD-diagram method, the apex coordinates are found to be (69$\fdg79\pm0\fdg11$, -30$\fdg82\pm0\fdg15$) for SAI 44 and (-56$\fdg22\pm0\fdg13$, -56$\fdg62\pm0\fdg13$) for SAI 45. The average space velocity components of the clusters SAI 44 and SAI 45 are calculated in units of km s$^{-1}$ as (-15.14$\pm$3.90, -19.43$\pm$4.41, -20.85$\pm$4.57) and (28.13$\pm$5.30, -9.78$\pm$3.13, -19.59$\pm$4.43), respectively.