Amplification of brightness variability by active-region nesting in Solar-like stars
[ X ]
Tarih
2020
Dergi Başlığı
Dergi ISSN
Cilt Başlığı
Yayıncı
Iop Publishing Ltd
Erişim Hakkı
info:eu-repo/semantics/closedAccess
Özet
Kepler observations revealed that hundreds of stars with near-solar fundamental parameters and rotation periods have much stronger and more regular brightness variations than the Sun. Here we identify one possible reason for the peculiar behavior of these stars. Inspired by solar nests of activity, we assume that the degree of inhomogeneity of active-region (AR) emergence on such stars is higher than on the Sun. To test our hypothesis, we model stellar light curves by injecting ARs consisting of spots and faculae on stellar surfaces at various rates and nesting patterns, using solar AR properties and differential rotation. We show that a moderate increase of the emergence frequency from the solar value combined with the increase of the degree of nesting can explain the full range of observed amplitudes of variability of Sun-like stars with nearly the solar rotation period. Furthermore, nesting in the form of active longitudes, in which ARs tend to emerge in the vicinity of two longitudes separated by 180 degrees, leads to highly regular, almost sine-like variability patterns, rather similar to those observed in a number of solar-like stars.
Açıklama
Shapiro, Alexander I./0000-0002-8842-5403; Isik, Emre/0000-0001-6163-0653
WOS:000574629500001
WOS:000574629500001
Anahtar Kelimeler
G Dwarf Stars, Solar Analogs, Stellar Activity, Starspots
Kaynak
Astrophysical Journal Letters
WoS Q Değeri
Q1
Scopus Q Değeri
Q1
Cilt
901
Sayı
1
