Zobrazeno 1 - 10
of 53
pro vyhledávání: '"P. Kajatkari"'
Autor:
Porceddu, Sebastian, Jetsu, Lauri, Markkanen, Tapio, Lyytinen, Joonas, Kajatkari, Perttu, Lehtinen, Jyri, Toivari-Viitala, Jaana
An ancient Egyptian Calendar of Lucky and Unlucky Days, the Cairo Calendar (CC), assigns luck with the period of 2.850 days. Previous astronomical, astrophysical and statistical analyses of CC support the idea that this was the period of the eclipsin
Externí odkaz:
http://arxiv.org/abs/1810.06412
Autor:
Siltala, L., Jetsu, L., Hackman, T., Henry, G. W., Immonen, L., Kajatkari, P., Lankinen, J., Lehtinen, J., Monira, S., Nikbakhsh, S., Viitanen, A., Viuho, J., Willamo, T.
Studying RS CVn binaries is challenging, because in addition to spot activity, other effects such as mass transfer between the components and gravitational distortion of their spherical forms may distort their light curves. Such effects can, however,
Externí odkaz:
http://arxiv.org/abs/1601.03536
Publikováno v:
A&A 588, A38 (2016)
We study a sample of 21 young and active solar-type stars with spectral types ranging from late F to mid K and characterize the behaviour of their activity. We apply the continuous period search (CPS) time series analysis method on 16 to 27 years of
Externí odkaz:
http://arxiv.org/abs/1509.06606
Publikováno v:
Journal of Shipping and Trade, Vol 5, Iss 1, Pp 1-15 (2020)
Abstract Emphasis on sustainability practices is growing globally in the shipping industry due to regulations on emissions from transportation as well as increasing customer demand for sustainability. This research aims to shed light on the environme
Externí odkaz:
https://doaj.org/article/3f9f4f0001e44cd99237ea9b5bda054d
We model the photometry of RS CVn star $\sigma$ Geminorum to obtain new information on the changes of the surface starspot distribution, i.e., activity cycles, differential rotation and active longitudes. We use the previously published Continuous Pe
Externí odkaz:
http://arxiv.org/abs/1311.1116
Autor:
Kajatkari, P., Jetsu, L., Cole, E., Hackman, T., Henry, G. W., Joutsiniemi, S-L., Lehtinen, J., Mäkelä, V., Porceddu, S., Ryynänen, K., Şolea, V.
Our aim was to study the light curve periodicity of the solar analogue V352 CMa and in particular show that the presence or absence of periodicity in low amplitude light curves can be modelled with the Continuous Period Search (CPS) method. We applie
Externí odkaz:
http://arxiv.org/abs/1310.4280
Autor:
Hackman, Thomas, Pelt, Jaan, Mantere, Maarit J., Jetsu, Lauri, Korhonen, Heidi, Granzer, Thomas, Kajatkari, Perttu, Lehtinen, Jyri, Strassmeier, Klaus G.
FK Comae is a rapidly rotating magnetically active star, the light curve of which is modulated by cool spots on its surface. It was the first star where the "flip-flop" phenomenon was discovered. Since then, flip-flops in the spot activity have been
Externí odkaz:
http://arxiv.org/abs/1211.0914
Autor:
Jetsu, L., Porceddu, S., Lyytinen, J., Kajatkari, P., Lehtinen, J., Markkanen, T., Toivari-Viitala, J.
The eclipses in binary stars give precise information of orbital period changes. Goodricke discovered the 2.867 days period in the eclipses of Algol in the year 1783. The irregular orbital period changes of this longest known eclipsing binary continu
Externí odkaz:
http://arxiv.org/abs/1204.6206
We investigate the spot activity of the young chromospherically active main sequence star LQ Hya. Our aims are to identify possible active longitudes, estimate the differential rotation and study long and short term changes in the activity. Our analy
Externí odkaz:
http://arxiv.org/abs/1203.1555
We formulate an improved time series analysis method for the analysis of photometry of active stars. This new Continuous Period Search (CPS) method is applied to 12 years of V band photometry of the young solar analogue HD 116956 (NQ UMa). The new me
Externí odkaz:
http://arxiv.org/abs/1007.4090