Browsing by Author "Carrera, R."
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- ItemA Chemical and Kinematical Analysis of the Intermediate-age Open Cluster IC 166 from APOGEE and Gaia DR2(2018) Schiappacasse-Ulloa, J.; Tang, B.; Fernandez-Trincado, J. G.; Zamora, O.; Geisler, D.; Frinchaboy, P.; Schultheis, M.; Dell'Agli, F.; Villanova, S.; Masseron, T.; Meszaros, Sz; Souto, D.; Hasselquist, S.; Cunha, K.; Smith, V. V.; Garcia-Hernandez, D. A.; Vieira, K.; Robin, A. C.; Minniti, D.; Zasowski, G.; Moreno, E.; Perez-Villegas, A.; Lane, R. R.; Ivans, I. I.; Pan, K.; Nitschelm, C.; Santana, F. A.; Carrera, R.; Roman-Lopes, A.
- ItemAtypical Mg-poor Milky Way Field Stars with Globular Cluster Second-generation-like Chemical Patterns(2017) Fernández Trincado J.; Zamora, O.; García Hernández, D.; Souto, D.; Dell'Agli, F.; Schiavon, R.; Geisler, D.; Tang, B.; Villanova, S.; Chanamé, Julio; Hasselquist, S.; Mennickent, R.; Cunha, K.; Shetrone, M.; Prieto, C.; Vieira, K.; Zasowski, G.; Sobeck, J.; Hayes, C.; Majewski, S.; Placco, V.; Beers, T.; Schleicher, D.; Robin, A.; Mészáros, S.; Masseron, T.; Pérez, A.; Anders, F.; Meza, A.; Alves-Brito A.; Carrera, R.; Minniti, D.; Lane, R.; Fernández-Alvar E.; Moreno, E.; Pichardo, B.; Pérez-Villegas, A.; Schultheis, M.; Roman-Lopes, A.; Fuentes, C.; Nitschelm, C.; Harding, P.; Bizyaev, D.; Pan, K.; Oravetz, D.; Simmons, A.; Ivans, I.; Blanco-Cuaresma, S.; Hernández J.; Alonso-García, J.; Valenzuela, O.
- ItemBaade's window and APOGEE Metallicities, ages, and chemical abundances(2017) Schultheis, M.; Rojas Arriagada, Alvaro; Pérez, A. E. García; Jönsson, H.; Hayden, M.; Nandakumar, G.; Cunha, K.; Prieto, C. Allende; Holtzman, J. A.; Beers, T. C.; Bizyaev, D.; Brinkmann, J.; Carrera, R.; Cohen, R. E.; Geisler, D.; Hearty, F. R.; Fernández-Trincado, J. G.; Maraston, C.; Minniti, D.; Nitschelm, C.; Roman-Lopes, A.; Schneider, D. P.; Tang, B.; Villanova, S.; Zasowski, G.; Majewski, S. R.
- ItemH-band discovery of additional second-generation stars in the Galactic bulge globular cluster NGC 6522 as observed by APOGEE and Gaia(2019) Fernandez-Trincado, J. G.; Zamora, O.; Souto, Diogo; Cohen, R. E.; Agli, F. Dell; Garcia-Hernandez, D. A.; Masseron, T.; Schiavon, R. P.; Meszaros, Sz; Cunha, K.; Hasselquist, S.; Shetrone, M.; Schiappacasse Ulloa, J.; Tang, B.; Geisler, D.; Schleicher, D. R. G.; Villanova, S.; Mennickent, R. E.; Minniti, D.; Alonso-Garcia, J.; Manchado, A.; Beers, T. C.; Sobeck, J.; Zasowski, G.; Schultheis, M.; Majewski, S. R.; Rojas-Arriagada, A.; Almeida, A.; Santana, F.; Oelkers, R. J.; Longa-Pena, P.; Carrera, R.; Burgasser, A. J.; Lane, R. R.; Roman-Lopes, A.; Ivans, I. I.; Hearty, F. R.We present an elemental abundance analysis of high-resolution spectra for five giant stars spatially located within the innermost regions of the bulge globular cluster NGC 6522 and derive Fe, Mg, Al, C, N, O, Si, and Ce abundances based on H-band spectra taken with the multi-object APOGEE-north spectrograph from the SDSS-IV Apache Point Observatory Galactic Evolution Experiment (APOGEE) survey. Of the five cluster candidates, two previously unremarked stars are confirmed to have second-generation (SG) abundance patterns, with the basic pattern of depletion in C and Mg simultaneous with enrichment in N and Al as seen in other SG globular cluster populations at similar metallicity. In agreement with the most recent optical studies, the NGC 6522 stars analyzed exhibit (when available) only mild overabundances of the s-process element Ce, contradicting the idea that NGC 6522 stars are formed from gas enriched by spinstars and indicating that other stellar sources such as massive AGB stars could be the primary polluters of intra-cluster medium. The peculiar abundance signatures of SG stars have been observed in our data, confirming the presence of multiple generations of stars in NGC 6522.
- ItemLow-resolution spectroscopy of main sequence stars belonging to 12 Galactic globular clusters I. CH and CN band strength variations(2010) Pancino, E.; Rejkuba, M.; Zoccali, M.; Carrera, R.Context. Globular clusters show star-to-star abundance variations for light elements that are not yet well understood. The preferred explanation involves a self-enrichment scenario, within which two subsequent generations of stars co-exist in globular clusters. Observations of chemical abundances in the main sequence and sub-giant branch stars allow us to investigate the signature of this chemically processed material without the complicating effects caused by stellar evolution and internal mixing.