s-Process Enhancement During the AGB Phase de Boer, E C Wylie; Cottrell, P L
The Ninth Torino Workshop on Evolution and Nucleosynthesis in AGB Stars and the Second Perugia Workshop on Nuclear Astrophysics (AIP Conference Proceedings Volume 1001),
01/2008, Letnik:
1001
Journal Article
Recenzirano
The results of a study of the AGB phase are presented. Abundances have been determined for Fe, C, O, the light s-process elements, Y and Zr, the heavy s-process elements, La and Nd, and the r-process ...element, Eu. The expected relationship between enhanced C, increasing C/O ratio and enhanced s-process elements has been quantified. Results are presented to provide observational data with which to compare theoretical predictions. This paper gives a brief overview of results, full details of the analysis and thorough discussion can be found in Wylie de Boer and Cottrell, 2008 1.
s-Process Element Abundance Results for 47 Tuc Stars Using SALT Worley, C C; Cottrell, P L; de Boer, E C Wylie
The Ninth Torino Workshop on Evolution and Nucleosynthesis in AGB Stars and the Second Perugia Workshop on Nuclear Astrophysics (AIP Conference Proceedings Volume 1001),
01/2008, Letnik:
1001
Journal Article
Recenzirano
Eleven giant branch stars in 47 Tucanae were observed using the Robert Stobie Spectro-graph (RSS) on the Southern African Large Telescope during the performance verification phase of this instrument. ...These stars were analysed as part of a quest to investigate s-process element abundances throughout the colour-magnitude diagram of 47 Tucanae. No abundance variations of Zr, Ba, Nd and Eu were found in these eleven stars, such that X/Fe = 0.0+/-0.5 3dex. Further, theoretical analysis indicates that the maximum resolution on RSS and AAOmega on the Anglo-Australian Telescope is sufficient to detect s-process element abundance variations. More detailed discussion on the abundance analysis of these stars and the theoretical analysis of spectrograph resolution can be found in l.
We describe the motivation, field locations and stellar selection for the ARGOS spectroscopic survey of 28,000 stars in the bulge and inner disk of the Milky Way galaxy across latitudes of b = -5 deg ...to -10 deg. The primary goal of this survey is to constrain the formation processes of the bulge and establish whether it is predominantly a merger or instability remnant. From the spectra (R = 11,000), we have measured radial velocities and determined stellar parameters, including metallicities and alpha/Fe ratios. Distances were estimated from the derived stellar parameters and about 14,000 stars are red giants within 3.5 kpc of the Galactic centre. In this paper, we present the observations and analysis methods. Subsequent papers (III and IV) will discuss the stellar metallicity distribution and kinematics of the Galactic bulge and inner disk, and the implications for the formation of the bulge.
The GALAH survey is a large high-resolution spectroscopic survey using the newly commissioned HERMES spectrograph on the Anglo-Australian Telescope. The HERMES spectrograph provides high-resolution ...(R ~28,000) spectra in four passbands for 392 stars simultaneously over a 2 degree field of view. The goal of the survey is to unravel the formation and evolutionary history of the Milky Way, using fossil remnants of ancient star formation events which have been disrupted and are now dispersed throughout the Galaxy. Chemical tagging seeks to identify such dispersed remnants solely from their common and unique chemical signatures; these groups are unidentifiable from their spatial, photometric or kinematic properties. To carry out chemical tagging, the GALAH survey will acquire spectra for a million stars down to V~14. The HERMES spectra of FGK stars contain absorption lines from 29 elements including light proton-capture elements, alpha-elements, odd-Z elements, iron-peak elements and n-capture elements from the light and heavy s-process and the r-process. This paper describes the motivation and planned execution of the GALAH survey, and presents some results on the first-light performance of HERMES.
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