96 citations · 651 across the 31 of their papers we have counts for
16 papers · 1 filter
CARMENES input catalog of M dwarfs: VII. New rotation periods for the survey stars and their correlations with stellar activity
Yutong Shan, Daniel Revilla, Sebastian L. Skrzypinski +40
Abridged: We measured photometric and spectroscopic for a large sample of nearby bright M dwarfs with spectral types from M0 to M9, as part of our continual effort to…
Prominence activation, optical flare, and post-flare loops on the RS Canum Venaticorum star SZ Piscium
Dongtao Cao, Shenghong Gu, Jian Ge +7
We present the results of time-resolved high-resolution spectroscopic observations of the very active RS Canum Venaticorum (RS CVn) star SZ Piscium (SZ Psc), obtained during two co…
Analysis of the public HARPS/ESO spectroscopic archive -- Ca II H&K time series for the HARPS radial velocity database
V. Perdelwitz, T. Trifonov, J. T. Teklu +2
Magnetic activity is currently the primary limiting factor in radial velocity (RV) exoplanet searches. Even inactive stars, such as the Sun, exhibit RV jitter of the order of a few…
The CARMENES search for exoplanets around M dwarfs. Variability on long timescales as seen in chromospheric indicators
B. Fuhrmeister, S. Czesla, V. Perdelwitz +19
It is clearly established that the Sun has an 11-year cycle that is caused by its internal magnetic field. This cycle is also observed in a sample of M dwarfs. In the framework of…
Chromospheric activity and photospheric variation of Ori during the great dimming event in 2020
M. Mittag, K. -P. Schröder, V. Perdelwitz +2
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…
Absolute dimensions and apsidal motion of the eclipsing binaries V889 Aql and V402 Lac
D. Baroch, A. Giménez, J. C. Morales +6
Double-lined eclipsing binaries allow the direct determination of masses and radii, which are key to test stellar models. With the launch of the TESS mission, many well-known eclip…
Probable Dormant Neutron Star in a Short-Period Binary System
Tsevi Mazeh, Simchon Faigler, Dolev Bashi +24
We have identified 2XMM J125556.57+565846.4, at a distance of 600 pc, as a binary system consisting of a normal star and a probable dormant neutron star. Optical spectra exhibit a…
Time evolution of magnetic activity cycles in young suns: The curious case of kappa Ceti
S. Boro Saikia, T. Lueftinger, C. P. Folsom +15
A detailed investigation of the magnetic properties of young Sun-like stars can provide valuable information on our Sun's magnetic past and its impact on the early Earth. We determ…
CARMENES input catalog of M dwarfs VI. A time-resolved Ca II H&K catalog from archival data
V. Perdelwitz, M. Mittag, L. Tal-Or +15
Radial-velocity (RV) jitter caused by stellar magnetic activity is an important factor in state-of-the-art exoplanet discovery surveys such as CARMENES. Stellar rotation, along wit…
Hybrid star HD 81817 accompanied by brown dwarf or substellar companion
Tae-Yang Bang, Byeong-Cheol Lee, V. Perdelwitz +4
HD 81817 is known as a hybrid star. Hybrid stars have both cool stellar wind properties and Ultraviolet (UV) or even X-ray emission features of highly ionized atoms in their spectr…
The first Doppler imaging of the active binary prototype RS Canum Venaticorum
Yue Xiang, Shenghong Gu, U. Wolter +6
We present the first Doppler images of the prototypical active binary star RS CVn, derived from high-resolution spectra observed in 2004, 2016 and 2017, using three different teles…
X-ray and UV emission of the ultrashort-period, low-mass eclipsing binary system BX Tri
V. Perdelwitz, S. Czesla, J. Robrade +2
Close binary systems provide an excellent tool to determine stellar parameters such as radii and masses with a high degree of precision. Due to the high rotational velocities, most…
Long-term variations in the X-ray activity of HR 1099
V. Perdelwitz, F. H. Navarrete, J. Zamponi +6
Although timing variations in close binary systems have been studied for a long time, their underlying causes are still unclear. A possible explanation is the so-called Applegate m…
A solar-like magnetic cycle on the mature K-dwarf 61 Cyg A (HD 201091)
S. Boro Saikia, S. V. Jeffers, J. Morin +9
The long-term monitoring of magnetic cycles in cool stars is a key diagnostic in understanding how dynamo generation and amplification of magnetic fields occur in stars similar in…
Eclipsing time variations in close binary systems: Planetary hypothesis vs. Applegate mechanism
M. Völschow, D. R. G. Schleicher, V. Perdelwitz +1
The observed eclipsing time variations in post-common-envelope binaries (PCEBs) can be interpreted as potential evidence for massive Jupiter-like planets, or as a result of magneti…
The nature of the 2014-2015 dim state of RW Aur revealed by X-ray, optical, and NIR observations
P. C. Schneider, H. M. Günther, J. Robrade +7
The binary system RW Aur consists of two classical T~Tauri stars (CTTSs). The primary recently underwent its second observed major dimming event (mag). We present new,…