First stars and reionization: Spinstars

Chiappini, Cristina

doi:10.1002/asna.201311902

Cited by 65 publications

(59 citation statements)

References 71 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…For instance, models based on enrichment by fast rotating stars (the so called "spinstars", see Chiappini 2013, for a review) predict an enhancement in 14 N and 13 C, a correlation between [N/Fe] and [Al/Fe], and a modest enhancement in 12 C, as well as some contribution to the s-process nucleosynthesis. While the nitrogen enhancement and its correlation with aluminium are corroborated by the data, observations at face value are at odds with predictions for carbon, which is depleted and in fact anti-correlated with nitrogen in the Nrich sample.…”

Section: Oldest Starsmentioning

confidence: 99%

Chemical tagging with APOGEE: discovery of a large population of N-rich stars in the inner Galaxy

Schiavon

Zamora

Carrera

et al. 2016

Mon. Not. R. Astron. Soc.

187

157

View full text Add to dashboard Cite

Formation of globular clusters (GCs), the Galactic bulge, or galaxy bulges in general, are important unsolved problems in Galactic astronomy. Homogeneous infrared observations of large samples of stars belonging to GCs and the Galactic bulge field are one of the best ways to study these problems. We report the discovery by APOGEE of a population of field stars in the inner Galaxy with abundances of N, C, and Al that are typically found in GC stars. The newly discovered stars have high [N/Fe], which is correlated with [Al/Fe] and anti-correlated with [C/Fe]. They are homogeneously distributed across, and kinematically indistinguishable from, other field stars in the same volume. Their metallicity distribution is seemingly unimodal, peaking at [Fe/H]∼-1, thus being in disagreement with that of the Galactic GC system. Our results can be understood in terms of different scenarios. N-rich stars could be former members of dissolved GCs, in which case the mass in destroyed GCs exceeds that of the surviving GC system by a factor of ∼8. In that scenario, the total mass contained in so-called "first-generation" stars cannot be larger than that in "second-generation" stars by more than a factor of ∼9 and was certainly smaller. Conversely, our results may imply the absence of a mandatory genetic link between "second generation" stars and GCs. Last, but not least, N-rich stars could be the oldest stars in the Galaxy, the by-products of chemical enrichment by the first stellar generations formed in the heart of the Galaxy.

show abstract

Section: Oldest Starsmentioning

confidence: 99%

Chemical tagging with APOGEE: discovery of a large population of N-rich stars in the inner Galaxy

Schiavon

Zamora

Carrera

et al. 2016

Mon. Not. R. Astron. Soc.

187

157

View full text Add to dashboard Cite

show abstract

“…There have been a number of advances in the theoretical description of the likely stellar progenitors of CEMP-no stars over the past decade (see Nomoto et al 2013, for a recent review on the subject). The suggested scenarios include the "spinstar" model (rapidly rotating, near-zerometallicity, massive stars; Meynet et al 2010;Chiappini 2013), the "faint supernovae (SNe)" that undergo mixing and fallback (Umeda & Nomoto 2005;Nomoto et al 2006;Tominaga et al 2014), and the metal-free massive stars from Heger & Woosley (2010).…”

Section: Introductionmentioning

confidence: 99%

OBSERVATIONAL CONSTRAINTS ON FIRST-STAR NUCLEOSYNTHESIS. II. SPECTROSCOPY OF AN ULTRA METAL-POOR CEMP-no STAR*

Placco

Frebel

Beers

et al. 2016

ApJ

View full text Add to dashboard Cite

We report on the first high-resolution spectroscopic analysis of HE0020-1741, a bright (V=12.9), ultra metal-.7) star selected from the Hamburg/ESO Survey. This star exhibits low abundances of neutron-capture elements ([ ] Ba Fe = −1.1) and an absolute carbon abundance A (C)=6.1; based on either criterion, HE0020-1741 is subclassified as a carbon-enhanced metal-poor star without enhancements in neutron-capture elements (CEMP-no). We show that the light-element abundance pattern of HE0020-1741 is consistent with predicted yields from a massive), primordial-composition, supernova (SN) progenitor. We also compare the abundance patterns of other ultra metal-poor stars from the literature with available measures of C, N, Na, Mg, and Fe abundances with an extensive grid of SN models (covering the mass range - M 10 100), in order to probe the nature of their likely stellar progenitors. Our results suggest that at least two classes of progenitors are required at [ ] Fe H < -4.0, as the abundance patterns for more than half of the sample studied in this work (7 out of 12 stars) cannot be easily reproduced by the predicted yields.

show abstract

“…Moreover, because oxygen is produced in large amounts by SN II, the C/O ratio tracks the relative contributions of low-to intermediate-mass stars versus massive stars in a given stellar population. Nitrogen is produced efficiently in intermediate-mass AGB stars (Karakas 2010), and there are suggestions in the literature (Chiappini 2013 and references therein) for an important contribution by massive stars as well. Analysis of integrated spectra of M31 globular clusters (Schiavon et al 2013) and earlytype galaxies (Schiavon 2007;Conroy et al 2014) suggests that secondary enrichment was important in these systems.…”

mentioning

confidence: 99%

The Apache Point Observatory Galactic Evolution Experiment (APOGEE)

et al. 2017

View full text Add to dashboard Cite

The Apache Point Observatory Galactic Evolution Experiment (APOGEE), one of the programs in the Sloan Digital Sky Survey III (SDSS-III), has now completed its systematic, homogeneous spectroscopic survey sampling all major populations of the Milky Way. After a three-year observing campaign on the Sloan 2.5 m Telescope, APOGEE has collected a half million high-resolution (R ∼ 22,500), high signal-to-noise ratio (>100), infrared (1.51–1.70 μm) spectra for 146,000 stars, with time series information via repeat visits to most of these stars. This paper describes the motivations for the survey and its overall design—hardware, field placement, target selection, operations—and gives an overview of these aspects as well as the data reduction, analysis, and products. An index is also given to the complement of technical papers that describe various critical survey components in detail. Finally, we discuss the achieved survey performance and illustrate the variety of potential uses of the data products by way of a number of science demonstrations, which span from time series analysis of stellar spectral variations and radial velocity variations from stellar companions, to spatial maps of kinematics, metallicity, and abundance patterns across the Galaxy and as a function of age, to new views of the interstellar medium, the chemistry of star clusters, and the discovery of rare stellar species. As part of SDSS-III Data Release 12 and later releases, all of the APOGEE data products are publicly available.

show abstract

First stars and reionization: Spinstars

Cited by 65 publications

References 71 publications

Chemical tagging with APOGEE: discovery of a large population of N-rich stars in the inner Galaxy

Chemical tagging with APOGEE: discovery of a large population of N-rich stars in the inner Galaxy

OBSERVATIONAL CONSTRAINTS ON FIRST-STAR NUCLEOSYNTHESIS. II. SPECTROSCOPY OF AN ULTRA METAL-POOR CEMP-no STAR*

The Apache Point Observatory Galactic Evolution Experiment (APOGEE)

Contact Info

Product

Resources

About