The GALAH Survey: Chemically tagging the Fimbulthul stream to the globular cluster ω Centauri

Simpson, Jeffrey D.; Martell, Sarah L.; Costa, G. S. Da; Horner, Jonathan; Wyse, Rosemary F. Ġ.; Ting, Yuan-Sen; Asplund, Martin; Bland-Hawthorn, Joss; Buder, Sven; Silva, Gayandhi M. De; Freeman, K. C.; Kos, Janez; Lewis, Geraint F.; Lind, Karin; Sharma, Sanjib; Zucker, D. B.; Zwitter, T.; Čotar, Klemen; Cottrell, P. L.; Nordlander, Thomas

doi:10.1093/mnras/stz3105

Cited by 23 publications

(17 citation statements)

References 97 publications

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“…Dating back to Lloyd Evans (1983), a bimodal behavior has now been established; for instance, from their highresolution analysis of 113 RR Lyr stars in ωCen Magurno et al (2019) reported solar [Y/Fe] values for stars more metal poor than approximately −1.5 dex, while the more metal-rich component showed enhanced element abundances. This is also seen in terms of a significantly larger scatter above that metallicity cut in the data of Simpson et al (2020), among others. Furthermore, the values for [La/Fe] found by Johnson & Pilachowski (2010) also show a clear bimodality.…”

Section: Fe-peak Elementssupporting

confidence: 51%

“…Similarly, genuine GCs are infamous for having a pronounced Na-O anticorrelation, which is also prominently seen in ωCen (Norris & Da Costa 1995b;Gratton et al 2011;Simpson et al 2020) and particularly extended below −1.3 dex (Marino et al 2011). In Fig.…”

Section: Light Elements: C N O Namentioning

confidence: 69%

“…In the following figures we place our results into context with the MW halo, bulge, and disks, and ωCen. For ωCen we used the data of Johnson & Pilachowski (2010) and Simpson et al (2020), who chemodynamically extracted cluster candidates from the GALAH survey (De Silva et al 2015). Here we also show the abundance ratios of those stars.…”

Section: Resultsmentioning

confidence: 99%

“…2. Sodium-oxygen anticorrelation using data from Marino et al (2011) and Simpson et al (2020), color-coded by metallicity. Star J110842 is indicated by a red star.…”

Section: Light Elements: C N O Namentioning

confidence: 99%

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Purveyors of fine halos

Koch

Hansen

Lombardo

et al. 2021

A&A

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Globular clusters (GCs) are important donors to the build-up of the Milky Way (MW) stellar halo, having contributed at the ten percent level over the Galactic history. Stars that originated from the second generation of dissolved or dissolving clusters can be readily identified via distinct light-element signatures such as enhanced N and Na and simultaneously depleted C and O abundances. In this paper we present an extensive chemical abundance analysis of the halo star J110842, which was previously kinematically associated with the massive MW GC ω Centauri (ωCen), and we discuss viable scenarios from escape to encounter. Based on a high-resolution, high signal-to-noise spectrum of this star using the UVES spectrograph, we were able to measure 33 species of 31 elements across all nucleosynthetic channels. The star's low metallicity of [Fe ii/H]=−2.10±0.02(stat.)±0.07(sys.) dex places it in the lower sixth percentile of ωCen's metallicity distribution. We find that all of the heavier-element abundances, from αand Fepeak elements to neutron-capture elements are closely compatible with ωCen's broad abundance distribution. However, given the major overlap of this object's abundances with the bulk of all of the MW components, this does not allow for a clear-cut distinction of the star's origin. In contrast, our measurements of an enhancement in CN and its position on the Na-strong locus of the Na-O anticorrelation render it conceivable that it originally formed as a second-generation GC star, lending support to a former association of this halo star with the massive GC ωCen.

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Section: Fe-peak Elementssupporting

confidence: 51%

Section: Light Elements: C N O Namentioning

confidence: 69%

Section: Resultsmentioning

confidence: 99%

“…2. Sodium-oxygen anticorrelation using data from Marino et al (2011) and Simpson et al (2020), color-coded by metallicity. Star J110842 is indicated by a red star.…”

Section: Light Elements: C N O Namentioning

confidence: 99%

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Purveyors of fine halos

Koch

Hansen

Lombardo

et al. 2021

A&A

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“…The search for field stars that were born in GCs (Lind et al 2015;Martell et al 2016;Fernández-Trincado et al 2015b, 2016a,b,c,d, 2020aSimpson et al 2020) is one clear example of the power of chemical tagging. This is possible because GCs appear to be the only environment responsible for the presence of light-element anti-correlations at all stellar evolutionary phases (e.g., Martell et al 2016;Pancino et al 2017;Bastian & Lardo 2018;Masseron et al 2019;Mészáros et al 2020), unless they are part of a binary system (Bastian & Lardo 2018;Fernández-Trincado et al 2019a), or part of the new kind of recently discovered anomalous Phosphorus-rich field stars (see, e.g., Masseron et al 2020).…”

Section: Introductionmentioning

confidence: 99%

Jurassic: A chemically anomalous structure in the Galactic halo

Fernández-Trincado

Beers

Minniti

2020

A&A

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Detailed elemental-abundance patterns of giant stars in the Galactic halo measured by the Apache Point Observatory Galactic Evolution Experiment (APOGEE-2) have revealed the existence of a unique and significant stellar subpopulation of silicon-enhanced ([Si/Fe] ≳ +0.5) metal-poor stars, spanning a wide range of metallicities (−1.5 ≲ [Fe/H] ≲ −0.8). Stars with over-abundances in [Si/Fe] are of great interest because these have very strong silicon (28Si) spectral features for stars of their metallicity and evolutionary stage, offering clues about rare nucleosynthetic pathways in globular clusters (GCs). Si-rich field stars have been conjectured to have been evaporated from GCs, however, the origin of their abundances remains unclear, and several scenarios have been offered to explain the anomalous abundance ratios. These include the hypothesis that some of them were born from a cloud of gas previously polluted by a progenitor that underwent a specific and peculiar nucleosynthesis event or, alternatively, that they were due to mass transfer from a previous evolved companion. However, those scenarios do not simultaneously explain the wide gamut of chemical species that are found in Si-rich stars. Instead, we show that the present inventory of such unusual stars, as well as their relation to known halo substructures (including the in situ halo, Gaia-Enceladus, the Helmi Stream(s), and Sequoia, among others), is still incomplete. We report the chemical abundances of the iron-peak (Fe), the light- (C and N), the α- (O and Mg), the odd-Z (Na and Al), and the s-process (Ce and Nd) elements of 55 newly identified Si-rich field stars (among more than ∼600 000 APOGEE-2 targets), which exhibit over-abundances of [Si/Fe] as extreme as those observed in some Galactic GCs, and they are relatively well distinguished from other stars in the [Si/Fe]−[Fe/H] plane. This new census confirms the presence of a statistically significant and chemically-anomalous structure in the inner halo: Jurassic. The chemo-dynamical properties of the Jurassic structure is consistent with it being the tidally disrupted remains of GCs, which are easily distinguished by an over-abundance of [Si/Fe] among Milky Way populations or satellites.

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The tidal tails of Milky Way globular clusters

Piatti

Carballo‐Bello

2020

A&A

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We report on the search for overall kinematical or structural conditions that have allowed some Milky Way globular clusters to develop tidal tails. For this purpose, we built a comprehensive catalog of globular clusters with studies focused on their outermost regions and we classify the globular clusters in three categories: those with observed tidal tails, those with extra-tidal features that are different from tidal tails, and those without any signatures of extended stellar density profiles. When exploring different kinematical and structural parameter spaces, we found that globular clusters behave similarly, irrespective of the presence of tidal tails or any other kind of extra-tidal feature, or the absence thereof. In general, globular clusters whose orbits are relatively more eccentric and very inclined, with respect to the Milky Way plane, have undergone a larger amount of mass loss by tidal disruption. The latter has also accelerated the internal dynamics toward a comparatively more advanced stage of evolution. These outcomes show that it is not straightforward to find any particular set of parameter space and dynamical conditions that can definitely predict tidal tails along globular clusters in the Milky Way.

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The GALAH Survey: Chemically tagging the Fimbulthul stream to the globular cluster ω Centauri

Cited by 23 publications

References 97 publications

Purveyors of fine halos

Purveyors of fine halos

Jurassic: A chemically anomalous structure in the Galactic halo

The tidal tails of Milky Way globular clusters

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