Please use this identifier to cite or link to this item: http://hdl.handle.net/2248/7470
 Title: Detection of a white dwarf companion to a blue straggler star in the outskirts of globular cluster NGC 5466 with the ultraviolet imaging telescope (UVIT) Authors: Snehalata SahuSubramaniam, ASimunovic, MirkoPostma, JCote, PatrickKameswara Rao, NGeller, Aaron MLeigh, NathanShara, MichaelPuzia, Thomas HStetson, Peter B Keywords: Blue stragglers;Globular clusters: individual (NGC 5466);Binaries: general;Ultraviolet: stars;White dwarfs Issue Date: 1-May-2019 Publisher: IOP Publishing Citation: The Astrophysical Journal, Vol. 876, No. 1, 34 Abstract: We report the discovery of a hot white dwarf (WD) companion to a blue straggler star (BSS) in the globular cluster (GC) NGC 5466, based on observations from the Ultra-Violet Imaging Telescope (UVIT) on board AstroSat. The Spectral Energy Distribution (SED) of the Far-UV detected BSS NH 84 was constructed by combining the flux measurements from four filters of UVIT, with GALEX, GAIA, and other ground-based observations. The SED of NH 84 reveals the presence of a hot companion to the BSS. The temperature and radius of the BSS (T ${}_{\mathrm{eff}}={8000}_{-250}^{+1000}$ K, R/R ${}_{\odot }=1.44\pm 0.05$) derived from Gemini spectra and SED fitting using Kurucz atmospheric models are consistent with each other. The temperature and radius of the hotter companion of NH 84 (T ${}_{\mathrm{eff}}={\rm{32,000}}\pm 2000$ K, R/R ${}_{\odot }=0.021\pm 0.007$) derived by fitting Koester WD models to the SED suggest that it is likely to be a hot WD. The radial velocity derived from the spectra along with the proper motion from GAIA DR2 confirms NH 84 to be a kinematic member of the cluster. This is the second detection of a BSS-WD candidate in a GC, and the first in the outskirts of a low-density GC. The location of this BSS in NGC 5466 along with its dynamical age supports the mass-transfer pathway for BSS formation in low-density environments. Description: Restricted Access URI: http://hdl.handle.net/2248/7470 ISSN: 0004-637X ???metadata.dc.rights???: © The American Astronomical Society ???metadata.dc.relation.uri???: https://doi.org/10.3847/1538-4357/ab11d0 Appears in Collections: IIAP Publications