NOAO >   Observing Info >   Approved Programs >   2012A-0391

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Proposal Information for 2012A-0391


PI: Paco Najarro, Center of Astrobiology, CAB, CSIC-INTA, Spain, najarro@cab.inta-csic.es
Address: Spain

CoI: Donald Figer, Rochester Institute of Technology (CIS)
CoI: Tom Geballe, Gemini Observatory - North
CoI: Diego de la Fuente, Center of Astrobiology, CAB, CSIC, Spain

Title: Metallicity in the Quintuplet Cluster and the Galactic Center: Evidence for a top-heavy star formation history?

Abstract: The Quintuplet Cluster, in our Galaxy, is one of the most massive resolved young clusters in the Local Group and is a test bed for understanding the star formation history of the region and for the top-heavy star formation scenario, via its alpha-elements and iron absolute abundances and their corresponding ratios. We have developed two different techniques to derive metallicity from infrared observations of LBVs and WR stars. For LBVs, absolute alpha-element (Si, Mg) and iron abundances may be obtained, while for WRs it is possible to derive the alpha-element (oxygen) abundance of the natal cloud. We propose to finish our partially completed 2011A Gemini program to obtain near-infrared spectra of the high-mass stars in the Quintuplet cluster and isolated massive stars in the inner Galactic Center region in order to extract stellar properties, ages, and abundances and hence address the top-heavy question. The excellent performance of GNIRS, especially at the shorter NIR wavelengths where extinction to the Galactic center is high allows us to extend spectral coverage of the Quintuplet Cluster stars to shorter wavelengths than previously and obtain for some stars new and crucial information on the Nitrogen abundance (metallicity) and temperature (stellar luminosity).


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