Zobrazeno 1 - 10
of 52
pro vyhledávání: '"Thomas Hackman"'
Autor:
Joonas Uusitalo, Kseniia Golubenko, Laura Arppe, Nicolas Brehm, Thomas Hackman, Hisashi Hayakawa, Samuli Helama, Kenichiro Mizohata, Fusa Miyake, Harri Mäkinen, Pekka Nöjd, Eija Tanskanen, Fuyuki Tokanai, Eugene Rozanov, Lukas Wacker, Ilya Usoskin, Markku Oinonen
Publikováno v:
Geophysical Research Letters, Vol 51, Iss 5, Pp n/a-n/a (2024)
Abstract The Carrington event of 1859 has been the strongest solar flare in the observational history. It plays a crucial role in shedding light on the frequency and impacts of the past and future Solar Energetic Particle (SEP) events on human societ
Externí odkaz:
https://doaj.org/article/a5b6ee8c0b6b470fbf2821ce683afea2
Publikováno v:
The Open Journal of Astrophysics, Vol 5, Iss 1 (2022)
Externí odkaz:
https://doaj.org/article/fec95e0a8f36447eb224981d71827f7e
Publikováno v:
Aalto University
Solar active regions (ARs) emerge on the Sun’s photosphere and they frequently produce flares and coronal mass ejections which are among major space weather drivers. Therefore, studying ARs can improve space weather forecast.The Mount Wilson Classi
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::536da61a6506da7695fe99e328b12cce
https://doi.org/10.5194/egusphere-egu2020-18577
https://doi.org/10.5194/egusphere-egu2020-18577
Global magnetic fields of active solar-like stars are nowadays routinely detected with spectropolarimetric measurements and are mapped with Zeeman-Doppler imaging (ZDI). However, due to the cancellation of opposite field polarities, polarimetry captu
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::52d74bad16d6114028d4819fde395228
https://aaltodoc.aalto.fi/handle/123456789/44012
https://aaltodoc.aalto.fi/handle/123456789/44012
Autor:
J. Lehtinen, Maarit J. Käpylä, Mariangela Viviani, Jörn Warnecke, Thomas Hackman, T. Willamo, N. Olspert
Publikováno v:
Astronomy & Astrophysics
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, but not much attention has been paid to the shape of cycles in other sta
Autor:
Joonas Uusitalo, Pekka Nöjd, G. A. Kovaltsov, Ilya Usoskin, Harri Mäkinen, Markku Oinonen, Laura Arppe, Kari Mielikäinen, V. Palonen, Thomas Hackman, Samuli Helama
Publikováno v:
Nature Communications, Vol 9, Iss 1, Pp 1-8 (2018)
Nature Communications
Nature Communications
Correction: Nature communications 10, article number: 1292 (2019) DOI: 10.1038/s41467-019-09214-w Recently, a rapid increase in radiocarbon (14C) was observed in Japanese tree rings at AD 774/775. Various explanations for the anomaly have been offere
Autor:
Thomas Hackman, Maarit J. Käpylä, Ilya Ilyin, J. Lehtinen, Oleg Kochukhov, Elizabeth M. Cole-Kodikara, Nikolai Piskunov
Publikováno v:
Astronomy & Astrophysics
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: during 2003--2009, a coherent spot structure migrating in the rotational
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::e00970917fa133d03b2217ffd364cc9e
http://hdl.handle.net/10138/305906
http://hdl.handle.net/10138/305906
Autor:
Harri Mäkinen, Markku Oinonen, Kari Mielikäinen, G. A. Kovaltsov, Pekka Nöjd, Laura Arppe, V. Palonen, Thomas Hackman, Samuli Helama, Joonas Uusitalo, Ilya Usoskin
Publikováno v:
Nature Communications
Nature Communications, Vol 10, Iss 1, Pp 1-2 (2019)
Nature Communications, Vol 10, Iss 1, Pp 1-2 (2019)
Recently, a rapid increase in radiocarbon (14C) was observed in Japanese tree rings at AD 774/775. Various explanations for the anomaly have been offered, such as a supernova, a γ-ray burst, a cometary impact, or an exceptionally large Solar Particl
Autor:
Nikolai Piskunov, Maarit J. Käpylä, T. Willamo, Thomas Hackman, Oleg Kochukhov, J. Lehtinen, Iya Ilyin
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 this research it is important to collect observation time series that
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::69943d68d74aa5bfb91794ec526dfdc8
http://arxiv.org/abs/1812.02013
http://arxiv.org/abs/1812.02013
Autor:
Maarit J. Käpylä, Gregory W. Henry, Oleg Kochukhov, T. Willamo, Ilya Ilyin, J. Lehtinen, Nikolai Piskunov, Lauri Jetsu, Thomas Hackman
Starspots are important manifestations of stellar magnetic activity. By studying their behaviour in young solar analogues, we can unravel the properties of their magnetic cycles. This gives crucial information of the underlying dynamo process. Compar
Externí odkaz:
https://explore.openaire.eu/search/publication?articleId=doi_dedup___::b812fe2f6f3513d6ef6306ebd5465e88