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		| Paper: | 
		Long-term Stellar Activity Variations of Stars from the HARPS M-dwarf Sample: Comparison Between Activity Indices | 
	 
	
		| Volume: | 
		448, 16th Cambridge Workshop on Cool Stars, Stellar Systems, and the Sun | 
	 
	
		| Page: | 
		1117 | 
	 
	
		| Authors: | 
		Gomes da Silva, J.; Santos, N. C.; Bonfils, X. | 
	 
	
	
		| Abstract: | 
		We used four known chromospheric activity indicators to measure long-term activity variations in a sample of 23 M-dwarf stars from the HARPS planet search program. We compared the indices using weighted Pearson correlation coefficients and found that in general (i) the correlation between SCaI I and Na I is very strong and does not depend on the activity level of the stars, (ii) the correlation between our SCaI I and Hα seems to depend on the activity level of the stars, and (iii) there is no strong correlation between SCaI I and He I for these type of stars. | 
	 
	
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