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Title: Determinations of the {sup 12}C/{sup 13}C Ratio for the Secondary Stars of AE Aquarii, SS Cygni, and RU Pegasi

Abstract

We present new moderate-resolution near-infrared spectroscopy of three CVs obtained using GNIRS on Gemini-North. These spectra covered three {sup 13}CO bandheads found in the K -band, allowing us to derive the isotopic abundance ratios for carbon. We find small {sup 12}C/{sup 13}C ratios for all three donor stars. In addition, these three objects show carbon deficits, with AE Aqr being the most extreme ([C/Fe] = −1.4). This result confirms the conjecture that the donor stars in some long-period CVs have undergone considerable nuclear evolution prior to becoming semi-contact binaries. In addition to the results for carbon, we find that the abundance of sodium is enhanced in these three objects, and the secondary stars in both RU Peg and SS Cyg suffer magnesium deficits. Explaining such anomalies appears to require higher mass progenitors than commonly assumed for the donor stars of CVs.

Authors:
;  [1]
  1. Department of Astronomy, New Mexico State University, Box 30001, MSC 4500, Las Cruces, NM 88003-8001 (United States)
Publication Date:
OSTI Identifier:
22663396
Resource Type:
Journal Article
Resource Relation:
Journal Name: Astrophysical Journal; Journal Volume: 843; Journal Issue: 2; Other Information: Country of input: International Atomic Energy Agency (IAEA)
Country of Publication:
United States
Language:
English
Subject:
79 ASTROPHYSICS, COSMOLOGY AND ASTRONOMY; ABSORPTION SPECTROSCOPY; ABUNDANCE; AUGER ELECTRON SPECTROSCOPY; CARBON 12; CARBON 13; INFRARED SPECTRA; ISOTOPE RATIO; MAGNESIUM; MASS; NOVAE; RESOLUTION; SODIUM; STAR EVOLUTION; STARS

Citation Formats

Harrison, Thomas E., and Marra, Rachel E., E-mail: tharriso@nmsu.edu, E-mail: rmarra@nmsu.edu. Determinations of the {sup 12}C/{sup 13}C Ratio for the Secondary Stars of AE Aquarii, SS Cygni, and RU Pegasi. United States: N. p., 2017. Web. doi:10.3847/1538-4357/AA7946.
Harrison, Thomas E., & Marra, Rachel E., E-mail: tharriso@nmsu.edu, E-mail: rmarra@nmsu.edu. Determinations of the {sup 12}C/{sup 13}C Ratio for the Secondary Stars of AE Aquarii, SS Cygni, and RU Pegasi. United States. doi:10.3847/1538-4357/AA7946.
Harrison, Thomas E., and Marra, Rachel E., E-mail: tharriso@nmsu.edu, E-mail: rmarra@nmsu.edu. Mon . "Determinations of the {sup 12}C/{sup 13}C Ratio for the Secondary Stars of AE Aquarii, SS Cygni, and RU Pegasi". United States. doi:10.3847/1538-4357/AA7946.
@article{osti_22663396,
title = {Determinations of the {sup 12}C/{sup 13}C Ratio for the Secondary Stars of AE Aquarii, SS Cygni, and RU Pegasi},
author = {Harrison, Thomas E. and Marra, Rachel E., E-mail: tharriso@nmsu.edu, E-mail: rmarra@nmsu.edu},
abstractNote = {We present new moderate-resolution near-infrared spectroscopy of three CVs obtained using GNIRS on Gemini-North. These spectra covered three {sup 13}CO bandheads found in the K -band, allowing us to derive the isotopic abundance ratios for carbon. We find small {sup 12}C/{sup 13}C ratios for all three donor stars. In addition, these three objects show carbon deficits, with AE Aqr being the most extreme ([C/Fe] = −1.4). This result confirms the conjecture that the donor stars in some long-period CVs have undergone considerable nuclear evolution prior to becoming semi-contact binaries. In addition to the results for carbon, we find that the abundance of sodium is enhanced in these three objects, and the secondary stars in both RU Peg and SS Cyg suffer magnesium deficits. Explaining such anomalies appears to require higher mass progenitors than commonly assumed for the donor stars of CVs.},
doi = {10.3847/1538-4357/AA7946},
journal = {Astrophysical Journal},
number = 2,
volume = 843,
place = {United States},
year = {Mon Jul 10 00:00:00 EDT 2017},
month = {Mon Jul 10 00:00:00 EDT 2017}
}