215 citations · 471 across the 19 of their papers we have counts for
19 papers
On the stellar parameter dependence of the combined Fe I and Fe II chromospheric emission-line in the wings of the Ca II K line
Faiber Rosas-Portilla, Luis Zapata, Klaus-Peter Schröder +3
We present an analysis of the chromospheric emission of Fe I + Fe II in the wing of the Ca II K line of 21 G and K giant stars. Stellar parameters and absolute chromospheric fluxes…
Relationship between TIGRE solar S-index and USET Ca II K full disk images
G. Vanden Broeck, S. Bechet, F. Clette +3
Full disk observations of the solar chromosphere in the Ca II K line represent a valuable dataset for studies of solar magnetic activity. The S-index is widely used to investigate…
Revisiting the cycle-rotation connection for late-type stars
M. Mittag, J. H. M. M. Schmitt, K. -P. Schröder
We analyse the relation between the activity cycle length and the Rossby number and collected a sample of 44 main sequence stars with well-known activity cycle periods and rotation…
On the physical nature of the Wilson-Bappu effect: revising the gravity and temperature dependence
F. Rosas-Portilla, K. -P. Schröder, D. Jack
We present a sample of 32 stars of spectral types G and K, and luminosity classes I to V, with moderate activity levels, covering four orders of magnitude of surface gravity and a…
Yet another star in the Albireo system -- The discovery of Albireo Ad
D. Jack, K. -P. Schröder, M. Mittag +1
Context. Albireo is a well-known bright visual double star. It is still unclear if the components A and B form a gravitationally bound system. The component Albireo A is itself a b…
A new photometric study of M14 (NGC 6402): An interpretation of the Horizontal Branch and beyond
M. A. Yepez, A. Arellano Ferro, D. Deras +3
We present a CCD photometric study of the globular cluster M14. Particular attention is given to the variable stars. This allowed new classifications and cluster membership co…