Reference : Measuring rotation periods of solar-like stars using TIGRE. A study of periodic CaII ...
Scientific journals : Article
Physical, chemical, mathematical & earth Sciences : Space science, astronomy & astrophysics
http://hdl.handle.net/2268/192396
Measuring rotation periods of solar-like stars using TIGRE. A study of periodic CaII H+K S-index variability
English
Hempelmann, A. mailto [Universität Hamburg, Hamburger Sternwarte, Gojenbergsweg 112, 21029, Hamburg, Germany]
Mittag, M. [Universität Hamburg, Hamburger Sternwarte, Gojenbergsweg 112, 21029, Hamburg, Germany]
Gonzalez-Perez, J. N. [Universität Hamburg, Hamburger Sternwarte, Gojenbergsweg 112, 21029, Hamburg, Germany]
Schmitt, J. H. M. M. [Universität Hamburg, Hamburger Sternwarte, Gojenbergsweg 112, 21029, Hamburg, Germany]
Schröder, K. P. [Universidad de Guanajuato, Departamento de Astronomía, 37320, Guanajuato, Mexico]
Rauw, Gregor [Université de Liège - ULiège > > >]
1-Feb-2016
Astronomy and Astrophysics
586
A14
Yes
International
[en] stars: activity ; stars: solar-type ; stars: rotation
[en] Context. The rotation period of a star is a key parameter both for the stellar dynamo that generates magnetic fields as well as for stellar differential rotation. <BR /> Aims: We present the results from the first year of monitoring a sample of solar-like stars by the TIGRE facility in Guanajuato (Mexico), which will study rotation in solar analogs. <BR /> Methods: TIGRE is an automatically operating 1.2 m telescope equipped with an Échelle spectrograph with a spectral resolution of 20 000, which covers a spectral range of between 3800 and 8800 Å. A main task is the monitoring the stellar activity of cool stars, mainly in the emission cores of the CaII H and K lines. We observed a number of stars with a sampling between 1-3 days over one year. <BR /> Results: A total number of 95 stars were observed between August 1 2013 and July 31 2014, the total number of spectra taken for this program was appoximately 2700. For almost a third of the sample stars the number of observations was rather low (less than 20), mainly because of bad weather. Fifty-four stars show a periodic signal but often with low significance. Only 24 stars exhibit a significant period. We interpret these signals as stellar rotation. For about half of them the rotation periods were already previously known, in which case our period measurements are usually in good agreement with the literature values. Besides the periodic signals, trends are frequently observed in the time series. <BR /> Conclusions: TIGRE is obviously able to detect stellar rotation periods in the CaII H+K emission cores when the time series contains a sufficient number of data points. However, this is frequently not achievable during the wet summer season in Guanajuato. Hence, future estimates of rotation periods will concentrate on stars that are observable during the winter season from October until April.
Liège Space Research Institute - LiSRI
http://hdl.handle.net/2268/192396
10.1051/0004-6361/201526972
http://adsabs.harvard.edu/abs/2016A%26A...586A..14H

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