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Projecte llegit

Títol: La relación edad-metalicidad en el entorno solar revelada por el satélite Gaia

Estudiants que han llegit aquest projecte:

Director/a: REBASSA MANSERGAS, ALBERTO

Departament: FIS

Títol: La relación edad-metalicidad en el entorno solar revelada por el satélite Gaia

Data inici oferta: 17-12-2024     Data finalització oferta: 17-07-2025


Estudis d'assignació del projecte:
    GR ENG SIST AEROESP
Tipus: Individual
 
Lloc de realització: EETAC
 
Segon director/a (UPC): RADDI, ROBERTO
 
Paraules clau:
Gaia satellite, white dwarfs, main sequence stars, age-metallicity
 
Descripció del contingut i pla d'activitats:
The age-metallicity relation provides information of the chemical evolution of the Milky Way. Given the difficulties in measuring stellar ages, this relation is observationally uncosntrained. However, thanks to the Gaia satellite, we have proper motions, parallaxes, photometry and spectra of billions of stars in the Galaxy. In this work we will make use of binary stars identified by Gaia composed of a white dwarf and a main sequence star to constrain the age-metallicity relation. White dwarfs are stellar remnants from which one can derive accurate stellar ages, since they simply cool down in time. Main sequence stars are typical stars like the Sun from which metallicities can be obtained. Since the two stars are coeval in each binary system, we will be able to observationally constrain the properties of the age-metallicity relation.

Measuring metallicities generally requires high-resolution spectroscopy. However, several recent studies have provided such values directly from Gaia photometry or even Gaia low-resolution spectra for millions of stars. The idea is to gather such information for all the main sequence stars that are in our Gaia sample and in common with those studies. These values, together with the white dwarf ages that we will measure interpolating the Gaia photometry in the white dwarf cooling models, will allow us to derive the observed age-metallicity relation.

This project is an extension of a long-term program that we are leading at the Group of Astronomy and Astrophysics based at the EETAC. It makes use of the superb astrometry, photometry and spectra provided by the Gaia satellite.
 
Overview (resum en anglès):
This Final Degree Project investigates the age-metallicity relation in the solar neighborhood, a key parameter for studying the chemical evolution of the Milky Way and the origin of planetary systems. In astrophysics, metallicity is defined as the proportion of elements heavier than helium in the atmosphere of stars, which are formed through nuclear fusion in their interiors and are fundamental for the formation of rocky planets.

Determining stellar ages with precision has long been a challenge. To address this issue, this project employs an innovative methodology based on the use of binary systems composed of a white dwarf and a main-sequence star. White dwarfs act as cosmic clocks to estimate the age of the system, while the main-sequence stars allow us to determine metallicities. Assuming that both components formed simultaneously, the age of the white dwarf can be directly associated with that of its main sequenc companion.

This study has been made possible thanks to the Gaia satellite, a revolutionary mission that has transformed our understanding of the Milky Way by providing astrometric, photometric, and spectroscopic data with unprecedented precision and volume.

The project is based on understanding the functioning of the Gaia satellite, as well as the collection and filtering of metallicity data obtained from the analysis of data provided by Gaia, combined with the calculation of white dwarf ages. The results show a lack of correlation between age and metallicity in the solar neighborhood, with a wide dispersion of metallicity values across all age ranges. This finding is consistent with previous studies and suggests that chemical evolution cannot be described by a simple temporal relation. Hypotheses such as local metal self-enrichment in star-forming regions or the migration of stars with different chemical compositions are proposed to explain this result.

This work reinforces the use of stellar binary systems as a reliable tool to study the age-metellicity relation and contributes to a future publication in the field of astronomy.

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