UOCS. IV. Discovery of diverse hot companions to blue stragglers in the old open cluster King 2
Vikrant V. Jadhav, Sindhu Pandey, Annapurni Subramaniam, Ram Sagar

TL;DR
This study used UVIT on extit{ASTROSAT} and Gaia data to identify diverse hot companions to blue straggler stars in the old open cluster King 2, revealing a significant fraction formed via mass transfer and diverse companion properties.
Contribution
It reports the discovery of hot companions to blue stragglers in King 2, showing their diversity and suggesting formation via mass transfer in a 6 Gyr old open cluster.
Findings
Six bright BSSs have hotter companions similar to EHB/sdB stars.
At least 15% of BSSs formed via mass transfer.
Hot companions can form in open clusters as young as 6 Gyr.
Abstract
King 2, one of the oldest clusters in the Milky Way, with an age of 6 Gyr and distance of pc, has been observed with UVIT payload on the \textit{ASTROSAT}. With membership information derived from {\it Gaia} EDR3, the cluster is found to have 39 blue straggler stars (BSSs). We created multi-wavelength spectra-energy distributions (SED) of all the BSSs. Out of 10 UV detected BSSs, 6 bright ones fitted with double component SEDs and were found to have hotter companions with properties similar to extreme horizontal branch (EHB)/subdwarf B (sdB) stars, with a range in luminosity and temperature, suggesting a diversity among the hot companions. We suggest that at least 15\% of BSSs in this cluster are formed via mass-transfer pathway. When we compared their properties to EHBs and hotter companions to BSS in open and globular clusters, we suggest that EHB/sdBs like…
Peer Reviews
No public reviews on file for this paper yet. If you reviewed it on a platform where reviews are public (OpenReview, ICLR, NeurIPS, ICML), you can paste yours below so the community can read it here.
Videos
No videos yet. Explain this paper in a talk, walkthrough, or lecture? Add one.
