Wavelets: a powerful tool for studying rotation, activity, and pulsation in Kepler and CoRoT stellar light curves

Aims. The wavelet transform has been used as a powerful tool for treating several problems in astrophysics. In this work, we show that the time-frequency analysis of stellar light curves using the wavelet transform is a practical tool for identifying rotation, magnetic activity, and pulsation signatures. We present the wavelet spectral composition and multiscale variations of the time series for four classes of stars: targets dominated by magnetic activity, stars with transiting planets, those with binary transits, and pulsating stars. Methods. We applied the Morlet wavelet (6th order), which offers high time and frequency resolution. By applying the wavelet transform to the signal, we obtain the wavelet local and global power spectra. The first is interpreted as energy distribution of the signal in time-frequency space, and the second is obtained by time integration of the local map. Results. Since the wavelet transform is a useful mathematical tool for nonstationary signals, this technique applied to Kepler and CoRoT light curves allows us to clearly identify particular signatures for different phenomena. In particular, patterns were identified for the temporal evolution of the rotation period and other periodicity due to active regions affecting these light curves. In addition, a beat-pattern signature in the local wavelet map of pulsating stars over the entire time span was also detected.Comment: Accepted for publication on A&

Melhoramento genético e produção de rainhas de Apis mellifera.

bitstream/item/87876/1/MELHORAMENTO-GENETICO.pd

Stellar parameters for stars of the CoRoT exoplanet field

Aims:To support the computation and evolutionary interpretation of periods associated with the rotational modulation, oscillations, and variability of stars located in the CoRoT fields, we are conducting a spectroscopic survey for stars located in the fields already observed by the satellite. These observations allow us to compute physical and chemical parameters for our stellar sample. Method: Using spectroscopic observations obtained with UVES/VLT and Hydra/Blanco, and based on standard analysis techniques, we computed physical and chemical parameters ($T_{\rm{eff}}$, $\log \,(g)$, $\rm{[Fe/H]}$, $v_{\rm{mic}}$, $v_{\rm{rad}}$, $v \sin \,(i)$, and $A(\rm{Li})$) for a large sample of CoRoT targets. Results: We provide physical and chemical parameters for a sample comprised of 138 CoRoT targets. Our analysis shows the stars in our sample are located in different evolutionary stages, ranging from the main sequence to the red giant branch, and range in spectral type from F to K. The physical and chemical properties for the stellar sample are in agreement with typical values reported for FGK stars. However, we report three stars presenting abnormal lithium behavior in the CoRoT fields. These parameters allow us to properly characterize the intrinsic properties of the stars in these fields. Our results reveal important differences in the distributions of metallicity, $T_{\rm eff}$, and evolutionary status for stars belonging to different CoRoT fields, in agreement with results obtained independently from ground-based photometric surveys. Conclusions: Our spectroscopic catalog, by providing much-needed spectroscopic information for a large sample of CoRoT targets, will be of key importance for the successful accomplishment of several different programs related to the CoRoT mission, thus it will help further boost the scientific return associated with this space mission.Comment: 43 pages, 17 figures, accepted for publication in A&

On the chromospheric activity of stars with planets

Context. Signatures of chromospheric activity enhancement have been found for a dozen stars, pointing to a possible star-planet interaction. Nevertheless in the coronal activity regime, there is no conclusive observational evidence for such an interaction. Does star-planet interaction manifest itself only for a few particular cases, without having a major effect on stars with planets in general? Aims. We aim to add additional observational constraints to support or reject the major effects of star-planet interactions in stellar activity, based on CaII chromospheric emission flux. Methods. We performed a statistical analysis of CaII emission flux of stars with planets, as well as a comparison between CaII and X-ray emission fluxes, searching for dependencies on planetary parameters. Results. In the present sample of stars with planets, there are no significant correlations between chromospheric activity indicator log(R'HK) and planetary parameters. Further, the distribution of the chromospheric activity indicator for stars without planets is not distinguishable from the one with planets.Comment: 6 pages, 5 figures, submitted to A&

Aplicação do diagnóstico rápido participativo para avaliação da percepção ambiental dos empregados da Embrapa Agroindústria de Alimentos.

bitstream/item/75070/1/pub-199.pd

Quality of tropical red wines from different varieties in the São Francisco Valley, Brazil.

The vitiviniculture at the São Francisco Valley, Brazil, is a recent and under development activity. It is located in the semi-arid of the northeast of Brazil, with socio-economic importance for the region, since the grape chain generates more than 80,000 direct and indirect jobs. The particular soil and climate conditions of the region, associated with the high incidence of radiation, winter absence and availability of water for irrigation, enable the production of grapes and wines of Vitis vinifera L. throughout the year, with two to three harvests per year, depending on the cycle of each variety

Quality of tropical white wines from different varieties produced in the São Francisco Valley, Brazil.

The vitiviniculture in the São Francisco Valley is recent and in full development activity. The production of grapes for fresh consumption was introduced in São Francisco Valley region in the 50s and the production of grapes for wines is a more recent activity with the first activities in the middle 80s with a great increase only in 2000. Nowadays the São Francisco Valley is the second largest producing region of fine wines using Vitis vinifera varieties in Brazil. The wine industry in the São Francisco Valley has unique soil and climate characteristics, differing from other traditional areas. It is located in semi-arid tropical climate zone, with an annual average temperature of 26ºC, high levels of solar radiation and maximum annual rainfall of approximately 500 mm. These factors, combined with the lack of winter and the availability of water for irrigation, allow the vines to have a continuous cycle, with production of grapes and wines throughout the year and up to three harvests per yea

Fenologia de espécies da floresta secundária potencialmente acumuladoras de fósforo.

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