An enquiry on the origins of N-rich stars in the inner Galaxy basedon APOGEE chemical compositions

Shobhit Kisku; Ricardo P. Schiavon; Danny Horta; Andrew Mason; J. Ted Mackereth; Sten Hasselquist; D. A. Garcia-Hernandez; Dmitry Bizyaev; Joel R. Brownstein; Richard R. Lane; Dante Minniti; Kaike Pan; Alexandre Roman-Lopes

doi:10.1093/mnras/stab525

arXiv · 2102.06720

An enquiry on the origins of N-rich stars in the inner Galaxy basedon APOGEE chemical compositions

Shobhit Kisku·Ricardo P. Schiavon·Danny Horta·Andrew Mason·J. Ted Mackereth·Sten Hasselquist·D. A. Garcia-Hernandez·Dmitry Bizyaev·Joel R. Brownstein·Richard R. Lane·Dante Minniti·Kaike Pan·Alexandre Roman-Lopes

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Abstract

Recent evidence based on APOGEE data for stars within a few kpc of the Galactic centre suggests that dissolved globular clusters (GCs) contribute significantly to the stellar mass budget of the inner halo. In this paper we enquire into the origins of tracers of GC dissolution, N-rich stars, that are located in the inner 4 kpc of the Milky Way. From an analysis of the chemical compositions of these stars we establish that about 30% of the N-rich stars previously identified in the inner Galaxy may have an accreted origin. This result is confirmed by an analysis of the kinematic properties of our sample. The specific frequency of N-rich stars is quite large in the accreted population, exceeding that of its in situ counterparts by near an order of magnitude, in disagreement with predictions from numerical simulations. We hope that our numbers provide a useful test to models of GC formation and destruction.

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Shobhit Kisku, Ricardo P. Schiavon, Danny Horta, Andrew Mason, J. Ted Mackereth, Sten Hasselquist, D. A. Garcia-Hernandez, Dmitry Bizyaev, Joel R. Brownstein, Richard R. Lane, Dante Minniti, Kaike Pan, Alexandre Roman-Lopes. 2021-02-12. An enquiry on the origins of N-rich stars in the inner Galaxy basedon APOGEE chemical compositions. https://doi.org/10.1093/mnras%2Fstab525

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