High resolution spectroscopic follow-up of the most metal-poor candidates from SkyMapper DR1.1

D. Yong; G. S. Da Costa; M. S. Bessell; A. Chiti; A. Frebel; X. Gao; K. Lind; A. D. Mackey; A. F. Marino; S. J. Murphy; T. Nordlander; M. Asplund; A. R. Casey; C. Kobayashi; J. E. Norris; B. P. Schmidt

doi:10.1093/mnras/stab2001

High resolution spectroscopic follow-up of the most metal-poor candidates from SkyMapper DR1.1

D. Yong, G. S. Da Costa, M. S. Bessell, A. Chiti, A. Frebel, X. Gao, K. Lind, A. D. Mackey, A. F. Marino, S. J. Murphy, T. Nordlander, M. Asplund, A. R. Casey, C. Kobayashi, J. E. Norris, B. P. Schmidt

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Abstract

We present chemical abundances for 21 elements (from Li to Eu) in 150 metal-poor Galactic stars spanning $-$4.1 $$ $-$3.5. Of the 20 objects for which we could measure nitrogen, 11 are nitrogen-enhanced metal-poor stars. Within our sample, the high NEMP fraction (55\% $\pm$ 21\%) is compatible with the upper range of predicted values (between 12\% and 35\%). The chemical abundance ratios [X/Fe] versus [Fe/H] exhibit similar trends to previous studies of metal-poor stars and Galactic chemical evolution models. We report the discovery of nine new r-I stars, four new r-II stars, one of which is the most metal-poor known, nine low-$\alpha$ stars with [$\alpha$/Fe] $\le$ 0.15 as well as one unusual star with [Zn/Fe] = +1.4 and [Sr/Fe] = +1.2 but with normal [Ba/Fe]. Finally, we combine our sample with literature data to provide the most extensive view of the early chemical enrichment of the Milky Way Galaxy.

Original language	English
Journal	Monthly Notices of the Royal Astronomical Society
DOIs	https://doi.org/10.1093/mnras/stab2001
Publication status	Published - 15 Jul 2021

Keywords

astro-ph.GA
astro-ph.SR

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Yong, D., Costa, G. S. D., Bessell, M. S., Chiti, A., Frebel, A., Gao, X., Lind, K., Mackey, A. D., Marino, A. F., Murphy, S. J., Nordlander, T., Asplund, M., Casey, A. R., Kobayashi, C., Norris, J. E., & Schmidt, B. P. (2021). High resolution spectroscopic follow-up of the most metal-poor candidates from SkyMapper DR1.1. Monthly Notices of the Royal Astronomical Society. https://doi.org/10.1093/mnras/stab2001

@article{1acc72948f9b4423aa37a1cf990d633c,

title = "High resolution spectroscopic follow-up of the most metal-poor candidates from SkyMapper DR1.1",

abstract = "We present chemical abundances for 21 elements (from Li to Eu) in 150 metal-poor Galactic stars spanning $-$4.1 $$ $-$3.5. Of the 20 objects for which we could measure nitrogen, 11 are nitrogen-enhanced metal-poor stars. Within our sample, the high NEMP fraction (55\% $\pm$ 21\%) is compatible with the upper range of predicted values (between 12\% and 35\%). The chemical abundance ratios [X/Fe] versus [Fe/H] exhibit similar trends to previous studies of metal-poor stars and Galactic chemical evolution models. We report the discovery of nine new r-I stars, four new r-II stars, one of which is the most metal-poor known, nine low-$\alpha$ stars with [$\alpha$/Fe] $\le$ 0.15 as well as one unusual star with [Zn/Fe] = +1.4 and [Sr/Fe] = +1.2 but with normal [Ba/Fe]. Finally, we combine our sample with literature data to provide the most extensive view of the early chemical enrichment of the Milky Way Galaxy. ",

keywords = "astro-ph.GA, astro-ph.SR",

author = "D. Yong and Costa, {G. S. Da} and Bessell, {M. S.} and A. Chiti and A. Frebel and X. Gao and K. Lind and Mackey, {A. D.} and Marino, {A. F.} and Murphy, {S. J.} and T. Nordlander and M. Asplund and Casey, {A. R.} and C. Kobayashi and Norris, {J. E.} and Schmidt, {B. P.}",

note = "{\textcopyright} 2021 The Author(s) Published by Oxford University Press on behalf of Royal Astronomical Society.",

year = "2021",

month = jul,

day = "15",

doi = "10.1093/mnras/stab2001",

language = "English",

journal = "Monthly Notices of the Royal Astronomical Society",

issn = "0035-8711",

publisher = "Oxford University Press (OUP)",

}

Yong, D, Costa, GSD, Bessell, MS, Chiti, A, Frebel, A, Gao, X, Lind, K, Mackey, AD, Marino, AF, Murphy, SJ, Nordlander, T, Asplund, M, Casey, AR, Kobayashi, C, Norris, JE & Schmidt, BP 2021, 'High resolution spectroscopic follow-up of the most metal-poor candidates from SkyMapper DR1.1', Monthly Notices of the Royal Astronomical Society. https://doi.org/10.1093/mnras/stab2001

TY - JOUR

T1 - High resolution spectroscopic follow-up of the most metal-poor candidates from SkyMapper DR1.1

AU - Yong, D.

AU - Costa, G. S. Da

AU - Bessell, M. S.

AU - Chiti, A.

AU - Frebel, A.

AU - Gao, X.

AU - Lind, K.

AU - Mackey, A. D.

AU - Marino, A. F.

AU - Murphy, S. J.

AU - Nordlander, T.

AU - Asplund, M.

AU - Casey, A. R.

AU - Kobayashi, C.

AU - Norris, J. E.

AU - Schmidt, B. P.

PY - 2021/7/15

Y1 - 2021/7/15

N2 - We present chemical abundances for 21 elements (from Li to Eu) in 150 metal-poor Galactic stars spanning $-$4.1 $$ $-$3.5. Of the 20 objects for which we could measure nitrogen, 11 are nitrogen-enhanced metal-poor stars. Within our sample, the high NEMP fraction (55\% $\pm$ 21\%) is compatible with the upper range of predicted values (between 12\% and 35\%). The chemical abundance ratios [X/Fe] versus [Fe/H] exhibit similar trends to previous studies of metal-poor stars and Galactic chemical evolution models. We report the discovery of nine new r-I stars, four new r-II stars, one of which is the most metal-poor known, nine low-$\alpha$ stars with [$\alpha$/Fe] $\le$ 0.15 as well as one unusual star with [Zn/Fe] = +1.4 and [Sr/Fe] = +1.2 but with normal [Ba/Fe]. Finally, we combine our sample with literature data to provide the most extensive view of the early chemical enrichment of the Milky Way Galaxy.

AB - We present chemical abundances for 21 elements (from Li to Eu) in 150 metal-poor Galactic stars spanning $-$4.1 $$ $-$3.5. Of the 20 objects for which we could measure nitrogen, 11 are nitrogen-enhanced metal-poor stars. Within our sample, the high NEMP fraction (55\% $\pm$ 21\%) is compatible with the upper range of predicted values (between 12\% and 35\%). The chemical abundance ratios [X/Fe] versus [Fe/H] exhibit similar trends to previous studies of metal-poor stars and Galactic chemical evolution models. We report the discovery of nine new r-I stars, four new r-II stars, one of which is the most metal-poor known, nine low-$\alpha$ stars with [$\alpha$/Fe] $\le$ 0.15 as well as one unusual star with [Zn/Fe] = +1.4 and [Sr/Fe] = +1.2 but with normal [Ba/Fe]. Finally, we combine our sample with literature data to provide the most extensive view of the early chemical enrichment of the Milky Way Galaxy.

KW - astro-ph.GA

KW - astro-ph.SR

U2 - 10.1093/mnras/stab2001

DO - 10.1093/mnras/stab2001

M3 - Article

SN - 0035-8711

JO - Monthly Notices of the Royal Astronomical Society

JF - Monthly Notices of the Royal Astronomical Society

ER -

High resolution spectroscopic follow-up of the most metal-poor candidates from SkyMapper DR1.1

Abstract

Keywords

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