Long-term chromospheric activity in southern m dwarfs: Gl 229 A and Gl 752 A
Several late-type stars present activity cycles similar to that of the Sun. However, these cycles have been mostly studied in F to K stars. Due to their small intrinsic brightness, M dwarfs are not usually the targets of long-term observational studies of stellar activity, and their long-term variab...
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| Autores principales: | , , , , |
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| Formato: | JOUR |
| Materias: | |
| Acceso en línea: | http://hdl.handle.net/20.500.12110/paper_00046256_v141_n2_p_Buccino |
| Aporte de: |
| Sumario: | Several late-type stars present activity cycles similar to that of the Sun. However, these cycles have been mostly studied in F to K stars. Due to their small intrinsic brightness, M dwarfs are not usually the targets of long-term observational studies of stellar activity, and their long-term variability is generally not known. In this work, we study the long-term activity of twoMdwarf stars: Gl 229 A (M1/2) and Gl 752 A (M2.5).We employ medium-resolution echelle spectra obtained at the 2.15 m telescope at the Argentinian observatory CASLEO between 2000 and 2010, and photometric observations obtained from the ASAS database. We analyze Ca ii K line-core fluxes and the mean V magnitude with the Lomb-Scargle periodogram, and we obtain possible activity cycles of ∼ 4 yr for Gl 229 A and ∼ 7 yr for Gl 752 A. © 2011. The American Astronomical Society. |
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