New suns in the cosmos. IV. The multifractal nature of stellar magnetic activity in kepler cool stars

dc.contributor.authorFreitas, D. B. de
dc.contributor.authorNepomuceno, M. M. F.
dc.contributor.authorSouza, M. Gomes de
dc.contributor.authorLeão, Isan Castro
dc.contributor.authorChagas, M. L. das
dc.contributor.authorCosta, A. D.
dc.contributor.authorMartins, Bruno Leonardo Canto
dc.contributor.authorMedeiros, José Renan de
dc.date.accessioned2020-06-01T00:46:31Z
dc.date.available2020-06-01T00:46:31Z
dc.date.issued2017
dc.description.resumoIn the present study, we investigate the multifractal nature of a long-cadence time series observed by the Kepler mission for a sample of 34 M dwarf stars and the Sun in its active phase. Using the Multifractal Detrending Moving Average algorithm, which enables the detection of multifractality in nonstationary time series, we define a set of multifractal indices based on the multifractal spectrum profile as a measure of the level of stellar magnetic activity. This set of indices is given by the (A, ${\rm{\Delta }}\alpha $, C, H)-quartet, where A, ${\rm{\Delta }}\alpha $, and C are related to geometric features from the multifractal spectrum and the global Hurst exponent H describes the global structure and memorability of time series dynamics. As a test, we measure these indices and compare them with a magnetic index defined as S ph and verify the degree of correlation among them. First, we apply the Poincaré plot method and find a strong correlation between the $\langle {S}_{\mathrm{ph}}\rangle $ index and one of the descriptors that emerges from this method. As a result, we find that this index is strongly correlated with long-term features of the signal. From the multifractal perspective, the $\langle {S}_{\mathrm{ph}}\rangle $ index is also strongly linked to the geometric properties of the multifractal spectrum except for the H index. Furthermore, our results emphasize that the rotation period of stars is scaled by the H index, which is consistent with Skumanich's relationship. Finally, our approach suggests that the H index may be related to the evolution of stellar angular momentum and a star's magnetic properties.pt_BR
dc.identifier.citationFREITAS, D. B. de ; NEPOMUCENO, M. M. F. ; GOMES DE SOUZA, M. ; LEÃO, I. C. ; CHAGAS, M. L. das ; COSTA, A. D. ; CANTO MARTINS, B. L. ; MEDEIROS, J. R. de. New Suns in the Cosmos. IV. The Multifractal Nature of Stellar Magnetic Activity in Kepler Cool Stars. The Astrophysical Journal, v. 843, p. 103, 2017. Disponívelem: http://iopscience.iop.org/article/10.3847/1538-4357/aa78aa/meta. Acesso em: 20 Maio 2020. https://doi.org/10.3847/1538-4357/aa78aapt_BR
dc.identifier.doi10.3847/1538-4357/aa78aa
dc.identifier.urihttps://repositorio.ufrn.br/jspui/handle/123456789/29111
dc.languageenpt_BR
dc.publisherThe American Astronomical Societypt_BR
dc.subjectData analysis – starspt_BR
dc.subjectActivity – starspt_BR
dc.subjectStars - rotationpt_BR
dc.subjectSolar- type - Sunpt_BR
dc.titleNew suns in the cosmos. IV. The multifractal nature of stellar magnetic activity in kepler cool starspt_BR
dc.typearticlept_BR

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