Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: UOCS. IV. Discovery of diverse hot companions to blue stragglers in the
  old open cluster King 2   King 2, one of the oldest clusters in the Milky Way, with an age of $\sim$ 6
Gyr and distance of $\sim 5700$ 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 companions can form in
binaries of open clusters as young as 6 Gyr.

31
The categories of this paper are: ao-sci
11
The categories of this paper are: hep-lat
25
The categories of this paper are: patt-sol
21
The categories of this paper are: adap-org
7
The categories of this paper are: hep-th
12
The categories of this paper are: nucl-th
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The categories of this paper are: stat
30
The categories of this paper are: q-alg
2
The categories of this paper are: math
3
The categories of this paper are: physics
17
The categories of this paper are: q-fin
23
The categories of this paper are: solv-int
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The categories of this paper are: funct-an
10
The categories of this paper are: q-bio
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The categories of this paper are: bayes-an
32
The categories of this paper are: atom-ph