48 citations · 346 across the 31 of their papers we have counts for
32 papers
Towards the Habitable Worlds Observatory: Retrieval of Reflection Spectra from Evolving Earth Analogues using 1D CNNs
Sarah G. A. Barbosa, Raissa Estrela, Paulo C. F. da Silva Filho +2
The Habitable Worlds Observatory (HWO) will characterize Earth-like exoplanets from low-resolution reflected-light spectra. To assess how atmospheric evolution shapes what can be r…
Anomalous Entropic Behavior Observed in Quasar 3C 273
C. V. da Silva, F. V. Alencar Filho, J. P. Bravo +1
We investigate the flux intensities spanning from radio waves to -rays across 36 light curves of Quasar 3C 273, utilizing publicly available data collected by the Integral Scien…
Star-planet interaction and its impact on the stellar rotation
Thiago M. Santiago, Sarah G. A. Barbosa, Francisco J. Cavalcante +1
The stellar rotation has an essential role in modifying the structure of the star and, therefore, the way these different interplays arise. On the other hand, changes in orbits imp…
Multifractal nature of seismic sequences distributed along the Pacific Ring of Fire
D. B. de Freitas, G. S. França
A multifractal methodology was utilized to analyze a set of seismic sequences distributed along the Pacific Ring of Fire, sourced from the National Earthquake Information Center (N…
Multiscale structure of the gravitational wave signal from GW150914 based on the nonextensivity -triplet
C. V. da Silva, M. M. F. Nepomuceno, D. B. de Freitas
We study the first gravitational wave, GW150914, detected by advanced LIGO and constructed from the data of measurement of strain relative deformation of the fabric of spacetime. W…
Hemispheric asymmetry in the sunspot cycle as a nonextensive phenomenon
Leonardo F. G. Batista, Thiago M. Santiago, Paulo C. F. da Silva Filho +2
The appearance of dark sunspots over the solar photosphere is not considered to be symmetric between the northern and southern hemispheres. Among the different conclusions obtained…
Fractal signature as a rotational modulation and stellar noise classifier based on the active Kepler stars
Paulo Cleber Farias da Silva Filho, Jose Ribamar Dantas Silveira Junior, Bricio Warney de Freitas Alves +5
In this study, we report on the analysis of 701 stars in a solar vicinity defined in three categories namely subsolar, solar, and supersolar with rotation periods between 1 and 70…
Measuring deviation from Skumanich braking index in active stars observed by Kepler mission
D. B. de Freitas, F. J. Cavalcante, T. M. Santiago
The aim of this work is to determine the deviation of the value of magnetic braking index from Skumanich canonical value for giant and main-sequence stars. In this contex…
Stellar age dependence of the nonextensive magnetic braking index: a test for the open cluster Per
Daniel B. de Freitas
Using a generalized function of the stellar spin-down law, we investigate the age dependence of the magnetic braking index (). Our survey includes 9 open clusters aged lower tha…
On the multiscale behaviour of stellar activity and rotation of the planet host Kepler-30
D. B. de Freitas, A. F. Lanza, F. O. da Silva Gomes +1
Kepler-30 is a unique target to study stellar activity and rotation in a young solar-like star accompanied by a compact planetary system. We use about 4 years of high-precision pho…
Non-extensive processes associated with heating of the Galactic disc
C. A. P. Viana, D. B. de Freitas
We analyse the mechanisms ruling galactic disc heating through the dynamics of space velocities , and , extracted from the Geneva-Copenhagen catalogue. To do this, we use…
Multifractal signatures of gravitational waves detected by LIGO
Daniel B. de Freitas, Mackson M. F. Nepomuceno, J. R. De Medeiros
We analyze the data from the 6 gravitational waves signals detected by LIGO through the lens of multifractal formalism using the MFDMA method, as well as shuffled and surrogate pro…
New Suns in the Cosmos V: Stellar rotation and multifractality in active \textit{Kepler} stars
D. B. de Freitas, M. M. F. Nepomuceno, L. D. Alves Rios +2
In the present study, high-precision time series photometry for the active \emph{Kepler} stars is described in the language of multifractals. We explore the potential of using the…
A nonextensive insight to the stellar initial mass function
D. B. de Freitas, R. T. Eufrasio, M. M. F. Nepomuceno +1
the present paper, we propose that the stellar initial mass distributions as known as IMF are best fitted by -Weibulls that emerge within nonextensive statistical mechanics. As…
New Suns in the Cosmos IV: the multifractal nature of stellar magnetic activity in \textit{Kepler} cool stars
D. B. de Freitas, M. M. F. Nepomuceno, M. Gomes de Souza +5
In the present study, we investigate the multifractal nature of a long-cadence time series observed by the \textit{Kepler} mission for a sample of 34 M dwarf stars and the Sun in i…
On the incidence of \textit{WISE} infrared excess among solar analog, twin and sibling stars
Antônio D. Costa, Bruno L. Canto Martins, Izan C. Leão +4
This study presents a search for IR excess in the 3.4, 4.6, 12 and 22 m bands in a sample of 216 targets, composed of solar sibling, twin and analog stars observed by the \texti…
New Suns in the Cosmos III: multifractal signature analysis
D. B. de Freitas, M. M. F. Nepomuceno, P. R. V. de Moraes Junior +7
In present paper, we investigate the multifractality signatures in hourly time series extracted from CoRoT spacecraft database. Our analysis is intended to highlight the possibilit…
Rotation period distribution of CoRoT and Kepler Sun-like stars
I. C. Leão, L. Pasquini, C. E. Ferreira Lopes +9
We study the distribution of the photometric rotation period (Prot), which is a direct measurement of the surface rotation at active latitudes, for three subsamples of Sun-like sta…
Stellar Cycles from Photometric Data: CoRoT Stars
C. E. Ferreira Lopes, I. C. Leão, D. B. de Freitas +3
Until a few years ago, the amplitude variation in the photometric data had been limitedly explored mainly because of time resolution and photometric sensitivity limitations. This i…
The variability behavior of CoRoT M-giant Stars
C. E. Ferreira Lopes, V. Neves, I. C. Leão +8
For 6 years the Convection, Rotation, and Planetary Transits (CoRoT) space mission has acquired photometric data from more than one hundred thousand point sources towards and direc…
A nonextensive view of the stellar braking indices
D. B. de Freitas, F. J. Cavalcante, B. B. Soares +1
The present work is based on a description for the angular mometum loss rate due to magnetic braking for main-sequence stars on the relationship between stellar rotation and age. I…
The rotational behavior of Kepler Stars with Planets
F. Paz-Chinchón, I. C. Leão, J. P. Bravo +6
We analyzed the host stars of the present sample of confirmed planets detected by Kepler and Kepler Objects of Interest (KOI) to compute new photometric rotation periods and to stu…
Chandrasekhar's relation and the stellar rotation in the Kepler field
J. R. P. Silva, B. B. Soares, D. B. de Freitas
According to the statistical law of large numbers, the expected mean of identically distributed random variables of a sample tends toward the actual mean as the sample increases. U…
Strong evidences for a nonextensive behavior of the rotation period in Open Clusters
D. B. de Freitas, M. M. F. Nepomuceno, B. B. Soares +1
Time-dependent nonextensivity in a stellar astrophysical scenario combines nonextensive entropic indices derived from the modified Kawaler's parametrization, and , obtai…