UVIT/AstroSat Investigation of a Low-luminous Blue Straggler Star in NGC 362: Detection of an Extremely Low-mass White Dwarf as Companion
Arvind Kumar Dattatrey,
Aryabhatta Research Institute of Observational Sciences, Manora Peak Nainital, 263001, India and Deen Dayal Upadhyay Gorakhpur University, Gorakhpur, Uttar Pradesh 273009, India. Corresponding author: arvind@aries.res.in
Ramakant Singh Yadav,
Deen Dayal Upadhyay Gorakhpur University, Gorakhpur, Uttar Pradesh 273009, India. Corresponding author: rkant@aries.res.in
Annapurni Subramaniam,
Indian Institute of Astrophysics, Koramangala, Bangalore 560034, India
Ravi Shankar Singh,
Deen Dayal Upadhyay Gorakhpur University, Gorakhpur, Uttar Pradesh 273009, India
Abstract
In the present study, we identified an extremely low-mass white dwarf as a companion to a low luminous blue straggler star within the Galactic globular cluster NGC 362. To conduct the analysis, we utilized data obtained from various sources, including AstroSat’s Ultra Violet Imaging Telescope, UVOT, and the 2.2 m ESO telescope. By examining the spectral energy distribution of the blue straggler star candidate, we successfully identified an extremely low-mass white dwarf as its binary companion. We determined the effective temperature, radius, and luminosity for both, the extremely low-mass white dwarf and the blue straggler star candidate. Specifically, the extremely low-mass white dwarf exhibits an effective temperature of 15000 K, a radius of 0.17 R⊙, a luminosity of 1.40 L⊙, and a mass range of 0.19-0.20 M⊙. Furthermore, the position of the straggler star within the cluster suggests their formation via the Case A/B mass-transfer mechanism in a low-density environment.
Keywords : Stars: blue straggler, Hertzsprung-Russell and CM diagrams, Globular star clusters: individual: NGC362
To cite this article
Arvind Kumar Dattatrey, Ramakant Singh Yadav, Annapurni Subramaniam & Ravi Shankar Singh, «UVIT/AstroSat Investigation of a Low-luminous Blue Straggler Star in NGC 362: Detection of an Extremely Low-mass White Dwarf as Companion», Bulletin de la Société Royale des Sciences de Liège [En ligne], Volume 93 - Année 2024, No 2 - Proceeedings of the 3rd BINA Workshop on the Scientific Potential of the Indo-Belgian Cooperation, 300-307 URL : http://popups.ulg.be/0037-9565/index.php?id=11687.
