Banca de DEFESA: MARIANA TEIXEIRA DE CASTRO

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : MARIANA TEIXEIRA DE CASTRO
DATE: 29/03/2023
TIME: 14:00
LOCAL: online
TITLE:

Stellar flares detected in light curves from the TESS mission.

KEY WORDS:

Stellar Flares; Stellar Activity; Subdwarf Stars; Photometry.

PAGES: 111
BIG AREA: Ciências Exatas e da Terra
AREA: Física
SUMMARY:

Stellar flares originate from the release of a large amount of energy resulting from variations in the magnetic field of a
star. These phenomena can be used as important observational markers of the magnetic activity of low-mass stars and also
influence the atmospheric and biological conditions of planets in their surroundings. In hot subdwarf stars (sdBs), such
phenomena are presumed to be caused by events external to the star due to its interaction with the magnetic field of a binary
pair. This Master's Dissertation aims at the detection and basic characterization of eruption signatures in light curves collected
by the Transiting Exoplanet Survey Satellite (TESS) mission. Starting from an initial sample of 924 stars belonging to the TESS
Objects of Interest (TOIs) catalog, observed in sectors 31 to 40, we identified potential eruption events in 52 stars. We
additionally considered two sdB stars previously studied in the literature, for which we identified, from the TESS light curves,
eruption events in the form of giant magnetic pulses. A statistical analysis based on the color-magnitude diagram of our
working sample reveals a tendency for more flares to occur and to have higher energy in main sequence stars compared to those
out from the main sequence, as well as for cool stars compared to hot stars. These results agree with the fact that main sequence
stars and cool stars have more developed convective zones, and therefore higher magnetic activity, than evolved or hot stars. In
general, this dissertation provides new constraints for further studies on stellar magnetic activity and eruptions.

COMMITTEE MEMBERS:
Interno - 1675216 - BRUNO LEONARDO CANTO MARTINS
Presidente - 3060853 - IZAN DE CASTRO LEÃO
Interno - 346785 - JOSE RENAN DE MEDEIROS
Externo à Instituição - MARCELO BORGES FERNANDES