UVIT Open Cluster Study. II. Detection of extremely low mass white dwarfs and post-mass transfer binaries in M67

Abstract

A detailed study of the ultraviolet (UV) bright stars in the old open star cluster, M67 is presented based on the far-UV observations using the {\it Ultra Violet Imaging Telescope} ({\it UVIT}) on {\it ASTROSAT}. The UV and UV-optical colour-magnitude diagrams (CMDs) along with overlaid isochrones are presented for the member stars, which include blue straggler stars (BSSs), triple systems, white dwarfs (WDs) and spectroscopic binaries (SB). The CMDs suggest the presence of excess UV flux in many members, which could be extrinsic or intrinsic to them. We construct multi-wavelength spectral energy distribution (SED) using photometric data from the {\it UVIT, Gaia} DR2, 2MASS and WISE surveys along with optical photometry. We fitted model SEDs to 7 WDs and find 4 of them have mass $>$ 0.5 \(M_\odot\) and cooling age of less than 200 Myr, thus demanding BSS progenitors. SED fits to 23 stars detect extremely low mass (ELM) WD companions to WOCS2007, WOCS6006 and WOCS2002, and a low mass WD to WOCS3001, which suggest these to be post mass transfer (MT) systems. 12 sources with possible WD companion need further confirmation. 9 sources have X-ray and excess UV flux, possibly arising out of stellar activity. This study demonstrates that UV observations are key to detect and characterise the ELM WDs in non-degenerate systems, which are ideal test beds to explore the formation pathways of these peculiar WDs. The increasing detection of post-MT systems among BSSs and main-sequence stars suggests a strong MT pathway and stellar interactions in M67.

arXiv comment29 pages, 13 figures, accepted in Astrophysical Journal

References in corpus (49)

• Gaia Data Release 2. Summary of the contents and survey properties
• The Wide-field Infrared Survey Explorer (WISE): Mission Description and Initial On-orbit Performance
• Correcting for the Effects of Interstellar Extinction
• The Galaxy Evolution Explorer: A Space Ultraviolet Survey Mission
• The propagation of uncertainties in stellar population synthesis modeling I: The relevance of uncertain aspects of stellar evolution and the IMF to the derived physical properties of galaxies
• The VizieR database of Astronomical Catalogues
• A large stellar evolution database for population synthesis studies. I. Scaled solar models and isochrones
• The propagation of uncertainties in stellar population synthesis modeling III: model calibration, comparison, and evaluation
• Binary and Millisecond Pulsars
• VOSA: Virtual Observatory SED Analyzer. An application to the Collinder 69 open cluster
• Spectroscopic Analysis of DA White Dwarfs: Stark Broadening of Hydrogen Lines Including Non-Ideal Effects
• The White Dwarf Initial-Final Mass Relation for Progenitor Stars From 0.85 to 7.5 M${}_{\odot }$
• Contact Binaries with Additional Components.I. The Extant Data
• On the triple origin of blue stragglers
• New white dwarf stars in the Sloan Digital Sky Survey Data Release 10
• The ELM Survey. I. A Complete Sample of Extremely Low Mass White Dwarfs
• Stellar Collisions and the Interior Structure of Blue Stragglers
• A Large Stellar Evolution Database for Population Synthesis Studies. III. Inclusion of the full Asymptotic Giant Branch phase and Web tools for stellar population analyses
• Ground-based CCD astrometry with wide field imagers. II. A star catalogue for M67: [email protected] MPG/ESO astrometry, FLAMES@VLT radial velocities
• Stellar Radial Velocities in the Old Open Cluster M67 (NGC 2682) I. Memberships, Binaries, and Kinematics
• The ELM Survey. VII. Orbital Properties of Low Mass White Dwarf Binaries
• EL CVn-type binaries - Discovery of 17 helium white dwarf precursors in bright eclipsing binary star systems
• The ELM Survey. V. Merging Massive White Dwarf Binaries
• Ultra Violet Imaging Telescope (UVIT) on ASTROSAT
• Relationship between X-ray and ultraviolet emission of flares from dMe stars observed by XMM-Newton
• Deep 2MASS Photometry of M67 and Calibration of the Main Sequence J-Ks Color Difference as an Age Indicator
• The timescale of low-mass proto-helium white dwarf evolution
• An Analytic Technique for Constraining the Dynamical Origins of Multiple Star Systems Containing Merger Products
• The K2 M67 Study: Revisiting old friends with K2 reveals oscillating red giants in the open cluster M67
• In-orbit Performance of UVIT and First Results
• The Hot Stars of Old Open Clusters: M67, NGC 188 and NGC6791
• Spectroscopy of Blue Stragglers and Turnoff Stars in M67 (NGC 2682)
• Blue Lurkers: Hidden Blue Stragglers on the M67 Main Sequence Identified from their Kepler/K2 Rotation Periods
• Time-Series Photometry of M67: W UMa Systems, Blue Stragglers, and Related Systems
• The Blue Straggler RS CVn Star S1082 in M67: A Detailed Light Curve and the Possibility of a Triple
• S1040 in M67: A Post-Mass-Transfer Binary with a Helium-Core White Dwarf
• A Chandra observation of the old open cluster M67
• The blue straggler S1082: a triple system in the old open cluster M67
• UVIT Open Cluster Study. I. Detection of a White Dwarf Companion to a Blue Straggler in M67: Evidence of Formation through Mass Transfer
• Close binary stars in the solar-age Galactic open cluster M67
• The Swift UVOT Stars Survey: I. Methods and Test Clusters
• Starspots in contact and semi-detached binary systems
• Ultraviolet stellar population of the old open cluster M67 (NGC 2682)
• Star clusters as laboratories for stellar and dynamical evolution
• A Chandra X-ray study of the interacting binaries in the old open cluster NGC6791
• Physical parameter study of eight W Ursae Majoris-type contact binaries in NGC 188
• A chemical study of M67 candidate blue stragglers and evolved blue stragglers observed with APOGEE DR14
• Ensemble Properties of the White Dwarf Population of the Old, Solar Metallicity Open Star Cluster Messier 67
• V1224 Cas - an EL CVn-type Eclipsing Binary Consisting of a Helium White Dwarf Precursor and a Delta Scuti Pulsator

Cited by in corpus (28)

• The ELM Survey. VIII. 98 Double White Dwarf Binaries
• UOCS VII. Blue Straggler Populations of Open Cluster NGC 7789 with UVIT/AstroSat
• UOCS. IV. Discovery of diverse hot companions to blue stragglers in the old open cluster King 2
• WIYN Open Cluster Study. LXXXVII. HST Ultraviolet Detection of Hot White Dwarf Companions to Blue Lurkers in M67
• 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
• UVIT/ASTROSAT studies of Blue Straggler stars and post-mass transfer systems in star clusters: Detection of one more blue lurker in M67
• Characterization of hot populations of Melotte 66 open cluster using Swift/UVOT
• Determination of dynamical ages of open clusters through the A${}^{+}$ parameter -- I
• GlobULeS-IV. UVIT/AstroSat detection of extremely low mass white dwarf companions to blue straggler stars in NGC 362
• Peculiarities in the horizontal branch stars of globular cluster NGC 1851: Discovery of a Blue straggler companion to an EHB star
• The White Dwarfs of the Old, Solar Metallicity Open Star Cluster Messier 67: Properties and Progenitors
• Discovery of double BSS sequences in the old Galactic open cluster Berkeley 17
• Hunting Down White Dwarf--Main Sequence Binaries Using Multi-Wavelength Observations
• UOCS-IX. AstroSat/UVIT study of the open cluster NGC 2818: Blue Stragglers, Yellow Stragglers, Planetary Nebula, and their membership
• M67 Blue Stragglers with High-resolution Infrared Spectroscopy
• UVIT Open Cluster Study. X. Rich Collection of Post Mass Transfer Systems in NGC 6791
• UOCS. XIV. Uncovering extremely low mass white dwarfs and blue lurkers in NGC 752
• The Blue Lurker WOCS 14020: A Long-Period Post-Common-Envelope Binary in M67 Originating from a Merger in a Triple System
• Dynamically Forming Extremely Low-Mass White Dwarf Binaries in Wide Orbits
• GlobULeS-V. UVIT/AstroSat studies of stellar populations in NGC 362: Detection of Blue Lurkers in a Globular Cluster
• UVIT study of UV bright stars in the globular cluster NGC 4147
• Photometric variability of blue straggler stars in M67 with TESS and K2
• Detection of a new sample of Galactic White Dwarfs in the direction of the Small Magellanic Cloud
• UOCS. V. UV study of the old open cluster NGC 188 using AstroSat
• A uvbyCaHbeta CCD Analysis of the Open Cluster Standard, M67,and its Relation to NGC 752
• A rotation-based census of blue lurker candidates in open clusters
• On the detectability and parameterisation of binary stars through spectral energy distributions