The Fall of a Giant. Chemical evolution of Enceladus, alias the Gaia Sausage
Date Issued
2019
Author(s)
•
•
•
Matteucci, Francesca
•
Silva Aguirre, Victor
•
•
Abstract
We present the first chemical evolution model for Enceladus, alias the Gaia Sausage, to investigate the star formation history of one of the most massive satellites accreted by the Milky Way during a major merger event. Our best chemical evolution model for Enceladus nicely fits the observed stellar [α/Fe]-[Fe/H] chemical abundance trends, and reproduces the observed stellar metallicity distribution function, by assuming low star formation efficiency, fast infall time-scale, and mild outflow intensity. We predict a median age for Enceladus stars 12.33^{+0.92}_{-1.36} Gyr, and - at the time of the merger with our Galaxy (≈10 Gyr ago from Helmi et al.) - we predict for Enceladus a total stellar mass M⋆ ≈ 5 × 109 M\odot. By looking at the predictions of our best model, we discuss that merger events between the Galaxy and systems like Enceladus may have inhibited the gas accretion on to the Galaxy disc at high redshifts, heating up the gas in the halo. This scenario could explain the extended period of quenching in the star formation activity of our Galaxy about 10 Gyr ago, which is predicted by Milky Way chemical evolution models, in order to reproduce the observed bimodality in [α/Fe]-[Fe/H] between thick- and thin-disc stars.
Volume
487
Issue
1
Start page
L47
Issn Identifier
1745-3925
Ads BibCode
2019MNRAS.487L..47V
Rights
open.access
File(s)![Thumbnail Image]()
Loading...
Name
slz070.pdf
Description
Pdf editoriale
Size
899.39 KB
Format
Adobe PDF
Checksum (MD5)
cba4193d36a722e3d35fd05abdb19107