NOAO >   Observing Info >   Approved Programs >   2016B-0127

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Program Information for 2016B-0127


PI: Zachary Maas, Indiana U., zmaas@indiana.edu
Address: Department of Astronomy, 319 Swain West, Bloomington, IN, 47405 USA

CoI: Catherine A Pilachowski, Indiana U.

Title: Measurements of the Chlorine Isotope Ratio in Cool Stars

Abstract: We propose to measure the chlorine 35/37 isotope ratio from HCl features at 3.7 microns, in M-giants, S-type, and carbon stars, using the Phoenix instrument on Gemini South. Chlorine isotope ratio measurements in the ISM were found to be between 1-5. This range is attributed to differences in nucleosynthesis origin; type Ia supernova have yield ratios 3.5 to 5.5 depending on the model parameters while core collapse supernova models produce chlorine yields with isotope ratios of 1-2.5 depending on mass and metallicity of the progenitor stars. We previously made the first measurement of the Cl isotope ratio in the star RZ Ari. We propose to extend our method and measure the Cl isotope ratio in a large sample of nearby cool disk stars to determine the range of Cl isotope values found in the solar neighborhood and compare ratios between late evolutionary type stars.

Program Type: Standard/Galactic

Scheduled Nights:
Run 1 (2016B):  GEM-S-SVC/PHNX -- 8.3hrs band 3 (GS-2016B-Q-77)


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NOAO >   Observing Info >   Approved Programs >   2016B-0127

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