Carbon isotopic ratios in giant stars in the globular clusters M4 and M22

Journal Article · Thu Jun 01 04:00:00 EDT 1989 · Astronomical Journal; (USA)

DOI:https://doi.org/10.1086/115107· OSTI ID:5711326

Smith, V V; Suntzeff, N B ^[1]

---

1. Texas Univ., Austin (USA)

The abundances of C-12 and C-13 have been determined for seven stars in the globular cluster M4 and five stars in M22. The analysis utilizes low-resolution IR spectra, obtained with the KPNO-FTS, of the first-overtone vibration-rotation (V-R) bands of CO near a wavelength of 2.3 microns. This resolution is sufficient to resolve the individual V-R bands of C-12O and C-13O. Spectrum synthesis was used to derive individual carbon-12 and -13 abundances. This method of using low-resoluion spectra to obtain abundances was tested by deriving C-isotopic abundances in ten G and K giants that have been studied at high resolution by previous investigators: good agreement is found between the low- and high-resolution analyses. The globular cluster giants, in general, exhibit very low C-12/C-13 ratios, with most having C-12/C-13 of less than 10. Results suggest that those low-mass, low-metallicity giants have undergone extensive mixing of CN-processed material into their atmospheres. These results are compared to previous analyses of both metal-poor field giants and globular cluster giants, and discussed in terms of deep mixing in these stars. 40 refs.

• OSTI ID: 5711326
• Journal Information: Astronomical Journal; (USA), Journal Name: Astronomical Journal; (USA) Vol. 97; ISSN 0004-6256; ISSN ANJOA
• Country of Publication: United States
• Language: English

Related Subjects

640102* -- Astrophysics & Cosmology-- Stars & Quasi-Stellar
Radio & X-Ray Sources
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ABUNDANCE
ATMOSPHERES
CARBON ISOTOPES
CHEMICAL COMPOSITION
GIANT STARS
INFRARED SPECTRA
ISOTOPE RATIO
ISOTOPES
LINE WIDTHS
MASS
MIXING
SPECTRA
SPECTROSCOPY
STAR CLUSTERS
STARS
STELLAR ATMOSPHERES