Banca de DEFESA: RILLCK GUILHERME DE SOUZA BARROS DE AMORIM

Uma banca de DEFESA de MESTRADO foi cadastrada pelo programa.
STUDENT : RILLCK GUILHERME DE SOUZA BARROS DE AMORIM
DATE: 19/07/2024
TIME: 15:00
LOCAL: Plataforma Google Meet
TITLE:

Analysis of the photometric variability of Sun-like stars observed by the TESS mission

KEY WORDS:

Stellar Variability; Flare; Solar Analogs; Light Curves.

PAGES: 131
BIG AREA: Ciências Exatas e da Terra
AREA: Astronomia
SUMMARY:

The TESS (Transiting Exoplanet Survey Satellite) space mission is revolutionizing the search for exoplanets using
the planetary transit technique through photometric observations, which are also capable of displaying signals of stellar
variability. Studying these variabilities in Sun-like bodies is fundamentally important for understanding the stellar dynamics of
targets that possess characteristics similar to the, until now, unique star that hosts a planet with life. From this perspective, in
this work, we analyze the photometric variability of Sun-like stars. The sample used was constructed considering photometric
and atmospheric parameters similar to those of the Sun. These parameters were obtained from Gaia DR3, and after refining the
sample, we obtained 4,932 targets. For the study of photometric variability, we used low-cadence light curves, with intervals of
2 minutes of exposure, from the TESS mission. We applied the following statistical methods: FFT (Fast Fourier Transform),
Lomb-Scargle periodogram, and wavelet map. At the end of the analysis, we obtained the following results: 329 targets with
light curves showing a rotational signal (corresponding to 6.67% of our sample), 288 targets with dubious modulation (5.84%),
467 targets with ambiguous signal (9.47%), 4 targets with a typical pulsating star signal (0.10%), 22 targets belonging to binary
systems (0.43%), and 3759 targets that did not show any modulation, being classified as noisy (76.21%). In general, we found
Sun-like stars that rotate with periods ranging from 0.410 to 10.452 days, with an average value of 4.507 days, meaning they
rotate faster than the Sun, which has a slow rotation (P ⊙ rot ∼ 25 days) around its own axis. Additionally, we recorded the
presence of stellar flares in 76 targets of our sample, with energies varying from the order of 10 32 to 10 35 ergs.

COMMITTEE MEMBERS:
Presidente - 1675216 - BRUNO LEONARDO CANTO MARTINS
Externo à Instituição - CARLOS EDUARDO FERREIRA LOPES
Interno - 3060853 - IZAN DE CASTRO LEÃO
Interno - 346785 - JOSE RENAN DE MEDEIROS