Abstract:
Are DY Persei Stars Cooler Cousins of R Coronae Borealis Stars?
Anirban Bhowmick
1
, Gajendra Pandey
1
, Vishal Joshi
2
, and N. M. Ashok
2
1
Indian Institute of Astrophysics, Koramangala, Bengaluru 560 034, India;
anirban@iiap.res.in
,
pandey@iiap.res.in
2
Physical Research Laboratory, Ahmedabad 380009, India;
vjoshi@prl.res.in
,
ashok@prl.res.in
Received 2017 December 5; revised 2018 January 24; accepted 2018 January 24; published 2018 February 21
Abstract
In this paper we present, for the
fi
rst time, the study of low resolution
H
- and
K
-band spectra of 7 DY Per type and
suspect stars, as well as DY Persei itself. We also observed
H
- and
K
-band spectra of 3 R Coronae Borealis
(
RCB
)
stars, 1 hydrogen-de
fi
cient carbon
(
HdC
)
star, and 14 cool carbon stars, including normal giants as comparisons.
High
12
C
/
13
Candlow
16
O
/
18
O ratios are characteristic featur
es of majority RCBs and HdCs. We have
estimated
16
O
/
18
O ratios of the program stars from
the relative strengths of the
12
C
16
Oand
12
C
18
Omolecular
bands observed in
K
-band. Our preliminary analysis suggests that
a quartet of the DY Per suspects, along with
DY Persei itself, seem to show isotopic rat
io strength consistent with that of RCB
/
HdC stars, whereas two of
them do not show signi
fi
cant
13
Cand
18
O in their atmospheres. Our analysi
s provides further indications that
DY Per type stars could be related to the RCB
/
HdC class of stars.
