TY  - GEN
N2  - This dissertation focuses on classical Cepheids and RR Lyrae stars as tracers of the recent star formation and the early assembly of the Milky Way, respectively.

I use data from the Gaia spacecraft to search for classical Cepheids in Galactic open clusters. I confirm (reject) several Cepheid-cluster associations considered in previous studies as bona-fide and identify new potential cluster Cepheid candidates. I also study the feasibility of using young cluster ages as tests of the Cepheid period-age relation, and conclude that their usage still faces difficulties due to their sparsely populated red giant branches, their stochastically sampled main-sequence turn-offs, and their quick dissolution.

I combine publicly available and proprietary data to study outer halo RR Lyrae stars, in the context of the Halo Outskirts with Variable Stars (HOWVAST) survey. Using Dark Energy Camera data, I search for distant halo RR Lyrae stars and detect ? 500 candidates, ? 25% of which are not reported in the literature, and 11 of which are new discoveries beyond 100 kpc. I use their pulsation properties and radial distribution to investigate the role that the accretion of satellites play in the formation and shape of the halo. Finally, I derive atmospheric parameters, chemical abundances, and kinematics for a sample of distant halo RR Lyrae stars using Magellan Inamori Kyocera Echelle spectra. I speculate about their origin, looking for hints of their association with satellites and stellar streams, and conclude that the accretion of sub-haloes contributes significantly to building up the outer halo.

The results of this thesis confirm the pivotal role of variable stars as tools to unveil the Milky Way?s evolution.
ID  - heidok32368
A1  - Medina Toledo, Gustavo Enrique
CY  - Heidelberg
TI  - Unveiling the Milky Way?s History Using Young & Old Population Variable Stars
Y1  - 2022///
UR  - https://archiv.ub.uni-heidelberg.de/volltextserver/32368/
AV  - public
ER  -