Zobrazeno 1 - 10
of 3 366
pro vyhledávání: '"Schroeder, K"'
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 the magnetic activity of stars, however, its connection to the coverag
Externí odkaz:
http://arxiv.org/abs/2407.04475
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 periods. We find a linear behaviour in the double-logarithmic relatio
Externí odkaz:
http://arxiv.org/abs/2306.05866
Publikováno v:
A&A 669, A9 (2023)
The so-called great dimming event of alpha Ori in late 2019 and early 2020 sparked our interest in the behaviour of chromospheric activity during this period. To study the timeline of chromospheric activity, we derive a S_MWO time series of TIGRE and
Externí odkaz:
http://arxiv.org/abs/2211.04967
Autor:
González-Perez, J. N., Mittag, M., Schmitt, J. H. M. M., Schröder, K. -P., Jack, D., Rauw, G., Nazé, Y.
TIGRE (Telescopio Internacional de Guanajuato Rob\'otico Espectrosc\'opico) has been operating in fully robotic mode in the Observatory La Luz (Guanajuato, Mexico) since the end of 2013. With its sole instrument, HEROS, an \'echelle spectrograph with
Externí odkaz:
http://arxiv.org/abs/2206.02832
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 representative range of effective temperature. For each star we obtain
Externí odkaz:
http://arxiv.org/abs/2203.16593
Publikováno v:
A&A 661, A49 (2022)
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 binary star. The orbital parameters of the Albireo Aa, Ac system have b
Externí odkaz:
http://arxiv.org/abs/2203.04222
Autor:
David, M., Sucker, K., Hameister, J., Gerull, F., Grams, H., Röhl, C., Schröder, K., Brosig, L., Scutaru, A.M., Debiak, M., Kolossa-Gehring, M.
Publikováno v:
In Indoor Environments October 2024 1(3)
We present a CCD $VI$ photometric study of the globular cluster M14. Particular attention is given to the variable stars. This allowed new classifications and cluster membership considerations. New variables are reported; 3 RRc, 18 SR and 1 SX Phe. T
Externí odkaz:
http://arxiv.org/abs/2201.02160
In this study, we consider chromospheric heating models for 55 Cancri in conjunction with observations. The theoretical models, previously discussed in Paper I, are self-consistent, nonlinear and time-dependent ab-initio computations encompassing the
Externí odkaz:
http://arxiv.org/abs/2104.14684
Autor:
Ahumada, J. A., Ferro, A. Arellano, Fierro, I. Bustos, Lázaro, C., Yepez, M. A., Schroeder, K. P., Calderón, J.
We present a new time-series VI CCD photometry of the globular cluster NGC 6397, from which we obtained and analysed the light curves of 35 variables carefully identified in the cluster field. We assessed the membership of the variables with an astro
Externí odkaz:
http://arxiv.org/abs/2104.05830