| Issue |
A&A
Volume 676, August 2023
|
|
|---|---|---|
| Article Number | A47 | |
| Number of page(s) | 8 | |
| Section | Galactic structure, stellar clusters and populations | |
| DOI | https://doi.org/10.1051/0004-6361/202345907 | |
| Published online | 07 August 2023 | |
UOCS
X. Rich collection of post-mass-transfer systems in NGC 6791⋆
1
Helmholtz-Institut für Strahlen- und Kernphysik, Universität Bonn, Nussallee 14-16, 53115 Bonn, Germany
e-mail: vikrantjadhav16@gmail.com
2
Inter-University Centre for Astronomy and Astrophysics (IUCAA), Post Bag 4, Ganeshkhind, Pune 411007, India
3
Indian Institute of Astrophysics, Koramangala II Block, Bangalore 560034, India
e-mail: purni@iiap.res.in; ramsagar@iiap.res.in
Received:
13
January
2023
Accepted:
27
June
2023
Aims. NGC 6791 is one of the richest old open clusters in the Milky Way. Its position above the Galactic plane and its number density make it an interesting middle ground between Galactic open and globular clusters. We aim to detect the UV-bright population of NGC 6791 using AstroSat/UVIT images in near-UV and far-UV filters and characterise the known post-mass-transfer systems such as blue straggler stars (BSSs).
Methods. We identified 20 members with large UV flux (out of 91 cluster members among 1180 detections) – which is suggestive of binarity, interactions, or stellar activity – using a multi-wavelength spectral energy distribution analysis.
Results. We characterised 62 isolated cluster members, including five hot subdwarfs (sdA/sdB). Additionally, we detected ten sdA/sdB/extremely low-mass (ELM) white dwarf-type candidates hidden alongside other cluster members. Additionally, we report the discovery of four candidate blue lurkers, which are main sequence stars with mass accretion history.
Conclusions. We report that this cluster has a variety of stellar (pre-)remnants, such as sdBs, sdAs, and ELM white dwarfs, which are by-products of binary evolution. These are likely to be post-mass-transfer binaries found throughout the evolutionary phases from the main sequence to the post-horizontal branch. Therefore, this dynamically old open cluster is unique, making it an ideal test bed for dynamical studies.
Key words: binaries: general / open clusters and associations: individual: NGC 6791 / ultraviolet: stars / catalogs
Full Table 2 is only available at the CDS via anonymous ftp to cdsarc.cds.unistra.fr (130.79.128.5) or via https://cdsarc.cds.unistra.fr/viz-bin/cat/J/A+A/676/A47
© The Authors 2023
Open Access article, published by EDP Sciences, under the terms of the Creative Commons Attribution License (https://creativecommons.org/licenses/by/4.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.
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