Astrochemistry

The CARMENES Search For Exoplanets Around M Dwarfs: Magnesium And Silicon Abundances Of K7-M5.5 Stars

By Keith Cowing

Status Report

astro-ph.SR

July 30, 2024

Filed under astro-ph.SR, astrochemistry, astrogeology, astronomy, CARMENES, FGK-type stars, M-dwarf, Magnesium, silicon, Spectroscopy

The CARMENES Search For Exoplanets Around M Dwarfs: Magnesium And Silicon Abundances Of K7-M5.5 Stars — LEFT: M dwarf abundance distributions for Mg and Si separated according to the kinematic membership of stars in the thick disc (TD), thick disc-thin disc transition (TD-D), thin disc (D), and young disc (YD), following the criteria of Montes et al. (2018) (see text for details). Mean values for each population are indicated by vertical lines. RIGHT: Top panel: [Si/Fe] vs. firon. The target stars are in orange while the black points correspond to the firon values computed from the Adibekyan et al. (2012) abundances. The fit through the M dwarf values is denoted with a blue line. Bottom panel: Histogram for the firon values of our sample. — astro-ph.SR

We present the abundances of magnesium (Mg) and silicon (Si) for 314 dwarf stars with spectral types in the interval K7.0-M5.5 (T_eff range ~4200-3050 K) observed with the CARMENES high-resolution spectrograph at the 3.5 m telescope at the Calar Alto Observatory.

Our analysis employs the BT-Settl model atmospheres, the radiative transfer code Turbospectrum, and a state-of-the-art selection of atomic and molecular data. These Mg and Si abundances are critical for understanding both the chemical evolution and assembly of the Milky Way and the formation and composition of rocky planets.

Our chemical abundances show a line-to-line scatter at the level of 0.1 dex for all studied spectral types. The typical error bar of our chemical abundance measurements is +- 0.11 dex (Mg) and +- 0.16 dex (Si) for all spectral types based on the comparison of the results obtained for stellar components of multiple systems. The derived abundances are consistent with the galactic evolution trends and observed chemical abundance distribution of earlier FGK-type stars in the solar neighbourhood.

Besides, our analysis provides compatible abundances for stars in multiple systems. In addition, we studied the abundances of different galactic stellar populations. In this paper, we also explore the relation of the Mg and Si abundances of stars with and without known planets.

H. M. Tabernero, Y. Shan, J. A. Caballero, C. Duque-Arribas, D. Montes, J. I. González Hernández, M. R. Zapatero Osorio, A. Schweitzer, Th. Henning, M. Cortés-Contreras, A. Quirrenbach, P. J. Amado, A. Reiners, I. Ribas, G. Bergond, J. C. Morales

Comments: 11 Pages, 5 figures. Accepted for publication in A&A
Subjects: Solar and Stellar Astrophysics (astro-ph.SR); Earth and Planetary Astrophysics (astro-ph.EP)
Cite as: arXiv:2407.19969 [astro-ph.SR] (or arXiv:2407.19969v1 [astro-ph.SR] for this version)
Submission history
From: Hugo Tabernero
[v1] Mon, 29 Jul 2024 13:00:53 UTC (1,212 KB)
https://arxiv.org/abs/2407.19969
Astrobiology,

Keith Cowing

Explorers Club Fellow, ex-NASA Space Station Payload manager/space biologist, Away Teams, Journalist, Lapsed climber, Synaesthete, Na’Vi-Jedi-Freman-Buddhist-mix, ASL, Devon Island and Everest Base Camp veteran, (he/him) 🖖🏻

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