Astronomy and Astrophysics – Astrophysics
Scientific paper
2007-03-19
Astron.Astrophys.469:309-317,2007
Astronomy and Astrophysics
Astrophysics
12 pages, including 11 figures and 2 tables. Accepted for publication in Astronomy and Astrophysics
Scientific paper
10.1051/0004-6361:20066503
The main chromospheric activity indicator is the S index, which is esentially the ratio of the flux in the core of the Ca II H and K lines to the continuum nearby, and is well studied basically for stars from F to K. Another usual chromospheric proxy is the H\alpha line, which is beleived to be tightly correlated with the Ca II index. In this work we characterize both chromospheric activity indicators, one associated with the H and K Ca II lines and the other with H\alpha, for the whole range of late type stars, from F to M. We present periodical medium-resolution echelle observations covering the complete visual range, which were taken at the CASLEO Argentinean Observatory. These observations are distributed along 7 years. We use a total of 917 flux-calibrated spectra for 109 stars which range from F6 to M5. We statistically study these two indicators for stars of different activity levels and spectral types. We directly derive the conversion factor which translate the known S index to flux in the Ca II cores, and extend its calibration to a wider spectral range. We investigate the relation between the activity measurements in the calcium and hydrogen lines, and found that the usual correlation observed is basically the product of the dependence of each flux with stellar colour, and not the product of similar activity phenomena.
Cincunegui Carolina
Díaz Rodrigo F.
Mauas Pablo J. D.
No associations
LandOfFree
Fluxes in Hαand Ca II H and K for a sample of Southern stars does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Fluxes in Hαand Ca II H and K for a sample of Southern stars, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Fluxes in Hαand Ca II H and K for a sample of Southern stars will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-122787