UOCS-VIII. UV Study of the open cluster NGC 2506 using ASTROSAT

Abstract

We study an intermediate-age open cluster NGC 2506 using the \textit{ASTROSAT}/UVIT data and other archival data. We identified 2175 cluster members using a machine learning-based algorithm, ML--MOC, on Gaia EDR3 data. Among the cluster members detected in UVIT filters, F148W, F154W, and F169M, we detect 9 blue straggler stars (BSS), 3 yellow straggler stars (YSS) and 3 red clump (RC) stars. We construct multi-wavelength spectral energy distributions (SEDs) of these objects to characterize them and to estimate their parameters. We discovered hot companions to 3 BSS, 2 YSS and 3 RC candidates and estimated their properties. The hot companions with estimated temperatures, T${}_{\mathrm{eff}}$ $\sim$ 13250--31000 K, are WDs of extremely low-mass ($\sim$ 0.20 M${}_{\odot }$), low-mass ($\sim$ 0.20--0.40 M${}_{\odot }$), normal mass ($\sim$ 0.40--0.60 M${}_{\odot }$), and high-mass ($\sim$ 0.8 M${}_{\odot }$). We suggest that systems with extremely low mass and low mass WDs as companions are formed via Case-A/Case-B mass transfer mechanism. A BSS is the likely progenitor of the high mass WD, as a star with more than the turn-off mass of the cluster is needed to form a high mass WD. Thus, systems with high mass WD are likely to be formed through merger in triple systems. We conclude that mass transfer as well as merger pathways of BSS formation are present in this cluster.

References in corpus (20)

• VOSA: Virtual Observatory SED Analyzer. An application to the Collinder 69 open cluster
• Dynamical age differences among coeval star clusters as revealed by blue stragglers
• The ELM Survey. I. A Complete Sample of Extremely Low Mass White Dwarfs
• A new library of theoretical stellar spectra with scaled-solar and alpha-enhanced mixtures
• A Binary Origin for Blue Stragglers in Globular Clusters
• Discovery of Carbon/Oxygen depleted Blue Straggler Stars in 47 Tucanae: the chemical signature of a mass-transfer formation process
• ML-MOC: Machine Learning (kNN and GMM) based Membership Determination for Open Clusters
• White dwarf-main sequence binaries from Gaia EDR3: the unresolved 100pc volume-limited sample
• Blue Straggler Stars in Open Clusters using Gaia: Dependence on Cluster Parameters and Possible Formation Pathways
• Binary coalescence from case A evolution -- mergers and blue stragglers
• Blue Straggler Populations of Seven Open Clusters with Gaia DR2
• The K2 M67 Study: An Evolved Blue Straggler in M67 from K2 Mission Asteroseismology
• The Swift UVOT Stars Survey: I. Methods and Test Clusters
• UOCS VII. Blue Straggler Populations of Open Cluster NGC 7789 with UVIT/AstroSat
• A population of binaries in the Asymptotic Giant Branch of 47 Tucanae?
• Oscillating Blue Stragglers, gamma Doradus stars and eclipsing binaries in the open cluster NGC2506
• UOCS.VI. UVIT/AstroSat detection of low-mass white dwarf companions to 4 more blue stragglers in M67
• UOCS. III. UVIT catalogue of open clusters with machine learning based membership using \textit{Gaia} EDR3 astrometry
• WIYN Open Cluster Study. LXXII. A uvbyCa Hbeta CCD Analysis of the Metal-Deficient Open Cluster, NGC 2506
• Extremely precise age and metallicity of the open cluster NGC 2506 using detached eclipsing binaries

Cited by in corpus (3)

• Discovery of double BSS sequences in the old Galactic open cluster Berkeley 17
• UOCS. XIV. Uncovering extremely low mass white dwarfs and blue lurkers in NGC 752
• Field blue straggler stars: Discovery of white dwarf companions to blue metal-poor stars using UVIT/AstroSat