60 citations · 165 across the 10 of their papers we have counts for
10 papers
Six decades of TIGRE and Mount Wilson chromospheric monitoring in the H and K lines: The quest for an understanding of solar-type activity
J. H. M. M. Schmitt, K. -P. Schröder, M. Mittag +3
The combined time series of the consistently calibrated chromospheric activity indicator, the S-index -- derived from Mount Wilson and TIGRE data -- now spans more than five decade…
Warm ionized gas in the blue compact galaxy Haro 14 viewed by MUSE. The diverse ionization mechanisms acting in low-mass starbursts
L. M. Cairós, J. N. González-Pérez, P. M. Weilbacher +1
We investigate the warm ionized gas in the blue compact galaxy (BCG) Haro 14 by means of integral field spectroscopic observations taken with the MUSE/VLT. The large FoV of MUSE an…
MUSE observations of the blue compact dwarf galaxy Haro 14. Data analysis and first results on morphology and stellar populations
L. M. Cairós, J. N. González-Pérez, P. M. Weilbacher +1
(Abriged) Blue compact galaxies (BCGs) are low-luminosity, metal-poor, gas-rich objects that form stars at high rates, excellent analogs to the high-redshift star-forming galaxy po…
Magnetic field and chromospheric activity evolution of HD75332: a rapid magnetic cycle in an F star without a hot Jupiter
E. L. Brown, S. C. Marsden, M. W. Mengel +10
Studying cool star magnetic activity gives an important insight into the stellar dynamo and its relationship with stellar properties, as well as allowing us to place the Sun's magn…
Time series of optical spectra of Nova V659 Sct
Dennis Jack, Klaus-Peter Schröder, Philippe Eenens +4
With our robotic 1.2 m TIGRE telescope, we were able to obtain eight optical spectra with intermediate resolution (R = 20,000) of the Nova V659 Sct during different phases of its o…
Intriguing X-ray and optical variations of the gamma Cas analog HD45314
G. Rauw, Y. Nazé, M. A. Smith +11
A growing number of Be and Oe stars, named the gamma Cas stars, are known for their unusually hard and intense X-ray emission. This emission could either trace accretion by a compa…
The Ca II infrared triplet's performance as an activity indicator compared to Ca II H and K
J. Martin, B. Fuhrmeister, M. Mittag +4
Aims. A large number of Calcium Infrared Triplet (IRT) spectra are expected from the GAIA- and CARMENES missions. Conversion of these spectra into known activity indicators will al…
Study of the variability of Nova V5668 Sgr, based on high resolution spectroscopic monitoring
D. Jack, J. de J. Robles Pérez, I. De Gennaro Aquino +9
We present results of our dense spectroscopic monitoring of Nova V5668 Sgr. Starting on March 19 in 2015, only a few days after discovery, we have obtained a series of spectra with…
Chromospheric activity and evolutionary age of the Sun and four solar twins
M. Mittag, K. -P. Schröder, A. Hempelmann +2
The activity levels of the solar-twin candidates HD 101364 and HD 197027 are measured and compared with the Sun, the known solar twin 18 Sco, and the solar-like star 51 Peg. Furthe…
Long-term stability of spotted regions and the activity-induced Rossiter-McLaughlin effect on V889 Herculis. A synergy of photometry, radial velocity measurements, and Doppler imaging
K. F. Huber, U. Wolter, S. Czesla +4
The young active G-dwarf star V889 Herculis (HD 171488) shows pronounced spots in Doppler images as well as large variations in photometry and radial velocity (RV) measurements. Ho…