Abstract—Using modern published data on velocities and spectroscopic definitions of chemical elements in stellar objects of the Galaxy, we investigated the relationship of chemical composition with the kinematics of different populations. The paper shows that the old stellar populations of the Galaxy, belonging (by the kinematic criterion) to the thick disk subsystem—globular clusters, field variables of the type RR Lyrae (lyrids), as well as close F– G dwarfs and field giants, have different chemical composition. In particular, the dwarfs and giants of the field are on average more metallic than the globular clusters and lyrids of the field. Moreover, the relative abundances of α-elements in the range [Fe/H] > −1.0 are the highest for globular clusters, and are the lowest for field variables of the RR Lyrae type. Based on the analysis of the nature of the dependences of [α/Fe] on [Fe/H] for these objects it was suggested that the thick disk subsystem in the Galaxy is composite and at least three components exist independently within it. The oldest one includes metal-rich globular clusters that formed from a single proto-galactic cloud shortly after the start of type Ia supernovae outbursts. Then the subsystem of field stars of a thick disk was formed as a result of “heating” of stars of already formed thin disk of the Galaxy by a rather massive dwarf satellite galaxy that fell on it. And finally, subsystems of field stars with the kinematics of not only a thick, but even a thin disk that fell on the Galaxy from this captured satellite galaxy.
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Notes
Actually, the dip in globular clusters is located at a slightly higher metallicity (see Borkova and Marsakov, 2000), but it’s more convenient to accept this round number used commonly.
http://vizier.u-strasbg.fr/viz-bin/VizieR? -source=J/AZh/95/54.
Note that the maxima of distributions in field stars of the thick disk have slightly higher metallicity than the average values due to long metal-poor “tails”.
Features of the change in each of the four α-elements can be seen in Figs. 2a–2d in Marsakov et al. (2018), which show that the lowest relative abundances are observed for titanium, although for other elements they are usually lower than the average for field stars.
REFERENCES
M. G. Abadi, J. F. Navarro, M. Steinmetz, and V. R. Eke, Astrophys. J. 597 (1), 21 (2003).
S. M. Andrievsky, J. R. D. Lepine, S. A. Korotin, et al. Monthly Notices Royal Astron. Soc. 428 (4), 3252 (2013).
V. Belokurov, D. Erkal, N. W. Evans, et al., Monthly Notices Royal Astron. Soc. 478 (1), 611 (2018).
T. Bensby, S. Feltzing, and I. Lundstrom, Astron. and Astrophys. 410, 527 (2003).
T. Bensby, S. Feltzing, and M. S. Oey, Astron. and Astrophys. 562, A71 (2014).
T. V. Borkova and V. A. Marsakov, Astronomy Reports 44 (10), 665 (2000).
C. B. Brook, D. Kawata, B. K. Gibson, and K. C. Freeman, Astrophys. J. 612 (2), 894 (2004).
A. A. Chemel, E. V. Glushkova, A. K. Dambis, et al., Astrophysical Bulletin 73 (2), 162 (2018).
G. Clementini, E. Carretta, R. Gratton, et al., Astron. J. 110, 2319 (1995).
A. K. Dambis, L. N. Berdnikov, A. Y. Kniazev, et al., Monthly Notices Royal Astron. Soc. 435 (4), 3206 (2013).
O. J. Eggen, D. Lynden-Bell, and A. R. Sandage, Astrophys. J. 136, 748 (1962).
R. G. Gratton, E. Carretta, F. Matteucci, and C. Sneden, Astron. and Astrophys. 358, 671 (2000).
W. E. Harris, arXiv:1012.3224 (2010).
A. Helmi, C. Babusiaux, H. H. Koppelman, et al., Nature 563 (7729), 85 (2018).
T. D. Kinman, Monthly Notices Royal Astron. Soc. 119, 538 (1959).
P. Kroupa, Monthly Notices Royal Astron. Soc. 330 (3), 707 (2002).
B. V. Kukarkin, Gobular star clusters. The general catalogue of globular star clusters of our galaxy, concerning information on 129 objects known before 1974 (1974). [in Russian].
S. Liu, G. Zhao, Y.-Q. Chen, et al., Research in Astronomy and Astrophysics 13 (11), 1307 (2013).
J. T. Mackereth, R. P. Schiavon, J. Pfeffer, et al., Monthly Notices Royal Astron. Soc. 482 (3), 3426 (2019).
V. A. Marsakov, M. L. Gozha, and V. V. Koval, Astronomy Reports 62 (1), 50 (2018).
V. A. Marsakov, M. L. Gozha, and V. V. Koval’, Astronomy Reports 63 (3), 203 (2019a).
V. A. Marsakov, V. V. Koval’, and M. L. Gozha, Astrophysical Bulletin 74 (4), 403 (2019b).
V. A. Marsakov, V. V. Koval’, and M. L. Gozha, Astronomy Reports 63 (4), 274 (2019c).
V. A. Marsakov, V. V. Koval’, V. V. Kovtyukh, and T. V. Mishenina, Astronomy Letters 39 (12), 851 (2013).
V. A. Marsakov and A. A. Suchkov, Soviet Astronomy Letters 2, 148 (1976).
V. A. Marsakov and A. A. Suchkov, Sov. Astron. 21, 700 (1977).
F. Matteucci, Astrophys. and Space Sci. 284 (2), 539 (2003).
W. W. Morgan, Astron. J. 64, 432 (1959).
J. X. Prochaska, S. O. Naumov, B. W. Carney, et al., Astron. J. 120 (5), 2513 (2000).
M. Salaris and A. Weiss, Astron. and Astrophys. 388, 492 (2002).
R. Schonrich and J. Binney, Monthly Notices Royal Astron. Soc. 396 (1), 203 (2009).
D. A. Van den Berg, K. Brogaard, R. Leaman, and L. Casagrande, Astrophys. J. 775 (2), 134 (2013).
K. A. Venn, M. Irwin, M. D. Shetrone, et al., Astron. J.128 (3), 1177 (2004).
R. Zinn, Astrophys. J. 293, 424 (1985).
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The authors are grateful to the anonymous referee for valuable comments that made the results of the work more reasonably presented.
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Authors are grateful to the Laboratory of Cosmic Microphysical Studies of the Structure and Dynamics of the Galaxy, Institute of Physics, Southern Federal University, for the support.
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Marsakov, V.A., Koval’, V.V. & Gozha, M.L. Inconsistency of Chemical Properties of Stellar Populations in the Thick Disk Subsystem of our Galaxy. Astrophys. Bull. 75, 21–30 (2020). https://doi.org/10.1134/S1990341320010058
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DOI: https://doi.org/10.1134/S1990341320010058