136 citations · 870 across the 34 of their papers we have counts for
35 papers
TESS flares and chromospheric variability in the Pleiades, the Hyades, and Praesepe
A. Görgei, K. Vida, B. Seli +5
Magnetic activity is a result of the interaction between rotation and dynamo processes in cool stars with outer convection zones. Since open cluster members share a common age, dis…
First Doppler image and starspot-corrected orbit for Andromedae: A multifaceted activity analysis
Ö. Adebali, K. G. Strassmeier, I. V. Ilyin +3
We quantify the effect of starspots for the orbital elements of the spotted RS CVn binary Andromedae ( And) and present an empirical correction. The aim is to obtain a more…
Magnetic activity in close binary systems
Zs. Kővári
Tidal forces in close binary systems have diverse impacts on magnetic activity. The synchronicity characteristic of close systems counteracts magnetic braking, thereby sustaining r…
Stellar flares, superflares and coronal mass ejections -- entering the Big data era
Krisztián Vida, Zsolt Kővári, Martin Leitzinger +6
Flares, sometimes accompanied by coronal mass ejections (CMEs), are the result of sudden changes in the magnetic field of stars with high energy release through magnetic reconnecti…
A star under multiple influences. Magnetic activity in V815 Her, a compact 2+2 hierarchical system
Zs. Kovari, K. G. Strassmeier, L. Kriskovics +7
We are conducting a comprehensive investigation of V815 Her using photometric and spectroscopic data to understand the origin of the activity and what influences it in the short an…
A confined dynamo: magnetic activity of the K-dwarf component in the pre-cataclysmic binary system V471 Tauri
Zs. Kővári, L. Kriskovics, K. Oláh +6
We scrutinize the red dwarf component in the eclipsing binary system V471 Tau in order to unravel relations between different activity layers from the stellar surface through the c…
Superflares on the late-type giant KIC 2852961 -- Scaling effect behind flaring at different energy levels
Zs. Kővári, K. Oláh, M. N. Günther +7
The most powerful superflares reaching 10erg bolometric energy are from giant stars. The mechanism behind flaring is supposed to be the magnetic reconnection, which is close…
A census of Coronal Mass Ejections on solar-like stars
M. Leitzinger, P. Odert, R. Greimel +8
Coronal Mass Ejections (CMEs) may have major importance for planetary and stellar evolution. Stellar CME parameters, such as mass and velocity, have yet not been determined statist…
Flaring activity of Proxima Centauri from TESS observations: quasi-periodic oscillations during flare decay and inferences on the habitability of Proxima b
Krisztián Vida, Katalin Oláh, Zsolt Kővári +3
We analyze the light curve of the M5.5 dwarf Proxima Centauri obtained by the TESS in Sectors 11 and 12. In the day-long light curve we identified and analyzed 72 flar…
Magnetic activity of the young solar analogue V1358 Ori
L. Kriskovics, Zs. Kővári, K. Vida +3
Young, fast rotating single stars can show dramatically different magnetic signatures and levels of magnetic activity as compared with the Sun. While losing angular momentum due to…
Surface magnetic activity of the fast-rotating G5-giant IN Comae, central star of the faint planetary nebula LoTr 5
Zs. Kővári, K. G. Strassmeier, K. Oláh +8
On the AGB, low to intermediate mass stars blow away their outer envelopes, forming planetary nebulae. Interaction between the planetary nebula and its central progenitor is poorly…
Transient Inverse-FIP Plasma Composition Evolution within a Confined Solar Flare
Deborah Baker, Lidia van Driel-Gesztelyi, David H. Brooks +9
Understanding elemental abundance variations in the solar corona provides an insight into how matter and energy flow from the chromosphere into the heliosphere. Observed variations…
Eclipsing Spotted Giant Star With K2 and Historical Photometry
K. Oláh, S. Rappaport, T. Borkovits +15
Context. Stars can maintain their observable magnetic activity from the PMS to the tip of the red giant branch. However, the number of known active giants is much lower than active…
No Sun-like dynamo on the active star Andromedae from starspot asymmetry
Rachael M. Roettenbacher, John D. Monnier, Heidi Korhonen +12
Sunspots are cool areas caused by strong surface magnetic fields inhibiting convection. Moreover, strong magnetic fields can alter the average atmospheric structure, degrading our…
Rotation--differential rotation relationships for late-type single and binary stars from Doppler imaging
Zs. Kővári, K. Oláh, L. Kriskovics +3
From our sample of spotted late-type stars showing surface differential rotation we find that the relationship between the rotation period and the surface shear coefficient $α=ΔΩ/Ω…
Antisolar differential rotation with surface lithium enrichment on the single K-giant V1192 Orionis
Zs. Kővári, K. G. Strassmeier, T. A. Carroll +7
Context: Stars with about 12 solar masses at the red giant branch (RGB) represent an intriguing period of stellar evolution, i.e. when the convective envelope interacts with the…
Time-series Doppler images and surface differential rotation of the effectively-single rapidly-rotating K-giant KU Pegasi
Zs. Kővári, A. Künstler, K. G. Strassmeier +6
According to most stellar dynamo theories, differential rotation (DR) plays a crucial role for the generation of toroidal magnetic fields. Numerical models predict surface differen…
Magnetic cycles at different ages of stars
K. Oláh, Zs. Kővári, K. Petrovay +4
We study the different patterns of interannual magnetic variability in stars on or near the lower main sequence, approximately solar-type (G-K dwarf) stars in time series of 36 yea…
Investigating magnetic activity in very stable stellar magnetic fields: long-term photometric and spectroscopic study of the fully convective M4 dwarf V374 Peg
K. Vida, L. Kriskovics, K. Oláh +8
The ultrafast-rotating () fully convective single M4 dwarf V374 Peg is a well-known laboratory for studying intense stellar activity in a stable magnet…
Antisolar differential rotation of the K1-giant sigma Geminorum revisited
Zs. Kovari, L. Kriskovics, A. Künstler +6
Context. Surface differential rotation and other global surface flows on magnetically active stars are among the observable manifestations of the stellar dynamo working underneath.…
Magnitude-range brightness variations of overactive K giants
K. Oláh, A. Moór, Zs. Kővári +4
We study three representative, overactive spotted K giants (IL Hya, XX Tri, and DM UMa) known to exhibit V-band light variations between 0.65-1.05 mags. Our aim is to find the orig…
Observing dynamos in cool stars
Zsolt Kovari, Katalin Olah
The main aim of this paper is to introduce the most important observables that help us to investigate stellar dynamos and compare those to the modeling results. We give an overview…
Lithium enrichment on the single active K1-giant DI Piscium -- Possible joint origin of differential rotation and Li enrichment
L. Kriskovics, Zs. Kővári, K. Vida +2
We investigate the surface spot activity of the rapidly rotating, lithium-rich active single K-giant DI Psc to measure the surface differential rotation and understand the mechanis…
Activity on a Li-rich giant: DI Psc revisited
Levente Kriskovics, Zsolt Kővári, Krisztián Vida +1
We present a new Doppler imaging study for the Li-rich single K-giant DI Psc. Surface temperature maps are reconstructed for two subsequent rotation cycles. From the time evolution…