37 citations · 62 across the 2 of their papers we have counts for
6 papers · 1 filter
Hidden magnetic fields of young suns
O. Kochukhov, T. Hackman, J. J. Lehtinen +1
Global magnetic fields of active solar-like stars are nowadays routinely detected with spectropolarimetric measurements and are mapped with Zeeman-Doppler imaging (ZDI). However, d…
Shapes of stellar activity cycles
T. Willamo, T. Hackman, J. J. Lehtinen +4
Magnetic activity cycles are an important phenomenon in both the Sun and other stars. The shape of the solar cycle is commonly characterised by a fast rise and a slower decline, bu…
Differences in the solar cycle variability of simple and complex active regions during 1996-2018
Shabnam Nikbakhsh, Eija Tanskanen, Maarit Käpylä +1
Aims. Our aim is to examine the solar cycle variability of magnetically simple and complex active region. Methods. We studied simple ( and ) and complex ( and ) acti…
Spot evolution on LQ Hya during 2006--2017: temperature maps based on SOFIN and FIES data
Elizabeth M. Cole-Kodikara, Maarit J. Käpylä, Jyri J. Lehtinen +4
Context. LQ Hya is one of the most frequently studied young solar analogue stars. Recently, it has been observed to show intriguing behaviour by analysing long-term photometry: dur…
Starspot activity of HD 199178. Doppler images from 1994--2017
Thomas Hackman, Iya Ilyin, Jyri J. Lehtinen +4
Context. Studying the spots of late-type stars is crucial for distinguishing between the various proposed dynamo mechanisms believed to be the main cause of starspot activity. For…
Contemporaneous Imaging Comparisons of the Spotted Giant Geminorum Using Interferometric, Spectroscopic, and Photometric Data
Rachael M. Roettenbacher, John D. Monnier, Heidi Korhonen +8
Nearby, active stars with relatively rapid rotation and large starspot structures offer the opportunity to compare interferometric, spectroscopic, and photometric imaging technique…