arXiv subjects

A. H. Sheikh

Publications and source records attributed to A. H. Sheikh.

2 recordsLinked to original sources

arXiv2026

Discovery of an Unbound Flyby Companion of UBC 63: In the Immediate Aftermath of a Close Encounter

We re-investigate the open cluster UBC 63 using the Gaia DR3 data and show that, rather than being a single cluster as previously classified, it is a compelling candidate for a double cluster undergoing an unbound flyby interaction. A GMM decomposition performed in the 5D astrometric space reveals the two statistically distinct components, namely UBC 63A (98 members, Age = 21 $\pm$ 4 Myr) and UBC 63B (148 members, Age = 562 $\pm$ 43 Myr). A significant age difference of $\Delta \mathrm{Age} = 541 \pm 43$ Myr between the clusters, rules out coeval formation. Their 3D separation of $60 \pm 29$ pc at the birth-epoch of the younger cluster, indicates that the clusters might have originated from the same molecular cloud complex. At present, the system exhibits a 3D separation of $26 \pm 8$ pc, with a relative velocity of $3.60 \pm 1.80$ km s$^{-1}$. Orbital integrations and \textit{N}-body simulations of the pair suggest that the systems had a close encounter, reaching a separation of $7 \pm 2$ pc only $\sim$~6 Myr ago and predict a rapid divergence to a separation of $491 \pm 213$ pc within the next $\sim$100 Myr. The low escape velocity ($V_{\rm esc} = 0.51 \pm 0.12$ km s$^{-1}$) of the system compared to the relative 3D velocity indicates that they are gravitationally unbound. Their low tidal factors, elongated structures and populations extending beyond the Jacobi radii may reflect a strong transient tidal interaction between the clusters.

astro-ph.GA↗

arXiv2024

A Statistical and Multiwavelength Photometric Analysis of a Young Embedded Open Star Cluster: IC 1590

We present a statistical and multiwavelength photometric studies of young open cluster IC 1590. We identified 91 cluster members using $Gaia$ DR3 astrometry data using ensemble-based unsupervised machine learning techniques. From $Gaia$ EDR3 data, we estimate the best-fitted parameters for IC 1590 using the Automated Stellar Cluster Analysis package (ASteCA) yielding the distance $d$ $\sim$ 2.87 $\pm$ 0.02 Kpc, age $\sim$ 3.54 $\pm$ 0.05 Myr, metallicity $z$ $\sim$ 0.0212 $\pm$ 0.003, binarity value of $\sim$ 0.558, and extinction $A_v$ $\sim$ 1.252 $\pm$ 0.4 mag for an $R_v$ value of $\sim$ 3.322 $\pm$ 0.23. We estimate the initial mass function slope of the cluster to be $α$ = 1.081 $\pm$ 0.112 for single stars and $α$ = 1.490 $\pm$ 0.051 for a binary fraction of $\sim$ 0.558 in the mass range 1 M$_{\odot}$ $\leq$ m(M$_{\odot}$) $\leq$ 100 M$_{\odot}$. The $G$-band luminosity function slope is estimated to be $\sim$ 0.33 $\pm$ 0.09. We use $(J-H)$ versus $(H-K_s)$ color-color diagram to identify young stellar objects (YSOs). We found that all the identified YSOs have ages $\leq$ 2 Myr and masses $\sim$ 0.35 - 5.5 M$_{\odot}$. We also fit the radial surface density profile. Using the galpy we performed orbit analysis of the cluster. The extinction map for the cluster region has been generated using the PNICER technique and it is almost similar to the dust structure obtained from the 500 $μ$$m$ dust continuum emissions map of $Herschel$ SPIRE. We finally at the end discussed the star formation scenario in the cluster region.

astro-ph.GA↗