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arXiv · 1802.06846

Are DY\,Persei stars cooler cousins of R Coronae Borealis stars?

Anirban Bhowmick·Gajendra Pandey·Vishal Joshi·N. M. Ashok
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Abstract

In this paper we present for the first time, the study of low resolution $H$- and $K$- band spectra of 7 DY\,Per type and suspects stars as well as DY\,Persei itself. We also observed $H$- and $K$- band spectra of 3 R Coronae Borealis (RCB) stars, 1 hydrogen-deficient carbon (HdC) star and 14 cool carbon stars including normal giants as comparisons. High $^{12}$C/$^{13}$C and low $^{16}$O/$^{18}$O ratios are characteristic features of majority RCBs and HdCs. We have estimated $^{16}$O/$^{18}$O ratios of the programme stars from the relative strengths of the $^{12}$C$^{16}$O and $^{12}$C$^{18}$O molecular bands observed in $K$- band. Our preliminary analysis suggest that a quartet of the DY\,Per suspects along with DY\,Persei itself seems to show isotopic ratio strength consistent with the ones of RCB/HdC stars whereas two of them do not show significant $^{13}$C and $^{18}$O in their atmospheres. Our analysis provides further indications that DY\,Per type stars could be related to RCB/HdC class of stars.

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Anirban Bhowmick, Gajendra Pandey, Vishal Joshi, N. M. Ashok. 2018-02-19. Are DY\,Persei stars cooler cousins of R Coronae Borealis stars?. https://doi.org/10.3847/1538-4357%2Faaaae4

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