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      https://www.ias.ac.in/article/fulltext/joaa/041/0045

    • Keywords

       

      Blue stragglers; open clusters and associations: individual:M67; stars: rotation; white dwarfs; ultraviolet: stars.

    • Abstract

       

      The blue straggler stars (BSSs) are main-sequence (MS) stars, which have evaded stellar evolution by acquiring mass while on the MS. The detection of extremely low mass (ELM) white dwarf (WD) companions to two BSSs and one yellow straggler star (YSS) from our earlier study using UVIT/AstroSat, aswell as WD companions to main-sequence stars (known as blue lurkers) suggest a good fraction of post-mass transfer binaries in M67. Using deeper UVIT observations, here we report the detection of another blue lurker in M67, with an ELM WD companion. The post-mass transfer systems with the presence of ELMWDs, including BSSs, are formed from Case A/B mass transfer and are unlikely to show any difference in surface abundances. We find a correlation between the temperature of the WD and the $\nu \sin i$ of the BSSs. We also find that the progenitors of the massive WDs are likely to belong to the hot and luminous group of BSSs in M67. The only detected BSS$+$WD system by UVIT in the globular cluster NGC 5466 has a normal WD and suggests that open cluster like environment might be present in the outskirts of low density globular clusters.

    • Author Affiliations

       

      ANNAPURNI SUBRAMANIAM1 SINDHU PANDEY1 2 VIKRANT V. JADHAV1 3 SNEHALATA SAHU1

      1. Indian Institute of Astrophysics, Sarjapur Road, Koramangala, Bangalore 560 034, India.
      2. Aryabhatta Research Institute of Observational Sciences, Manora Peak, Nainital 263001, India.
      3. Joint Astronomy Programme and Department of Physics, Indian Institute of Science, Bangalore 560 012, India.
    • Dates

       
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