Recent observations of AB Dor and interpretation

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dc.contributor.authorBudding, E.
dc.contributor.authorErdem, A.
dc.contributor.authorInnis, J. L.
dc.contributor.authorOlah, K.
dc.contributor.authorSlee, O. B.
dc.date.accessioned2025-01-27T20:24:54Z
dc.date.available2025-01-27T20:24:54Z
dc.date.issued2009
dc.departmentÇanakkale Onsekiz Mart Üniversitesi
dc.description.abstractWe use minimal empirical modelling techniques to interpret recent (2006-2007) photometry and spectroscopy of AB Dor. We compare, in particular, broadband (B and V) maculation effects with emission features in high-resolution Ca II K-line spectroscopy. We also compare emission effects in the Ca II K and H alpha lines observed at different rotational phases. We refer to a broader multiwavelength campaign, of which these optical data were a part, involving X-ray and microwave observations to be published later. The broadband light curves are characterized by one outstanding macula, whereas the emission lines suggest 4 possible main chromospheric activity sites ('faculae'). These appear at a similar latitude and with comparable size to the main umbra, but there are significant displacements in longitude. However, one strong facular concentration near phase zero may have a physical relationship to the main macula. The derived longitudes of these features would have been affected by differential rotation operating over the several months between the spectroscopic and photometric observations, but the difference of at least similar to 30 degrees between facula and umbra appears too great to allow their coincidence. The possibility of a large bipolar surface structure is considered, keeping in mind the bipolar character of solar activity centres: the activity of rapidly rotating cool stars being generally compared with that of the Sun, scaled up by a few orders of magnitude. Observed microwave activity may link to this same main photospheric and chromospheric centre picked up by the optical analysis. Characterization of macular and facular contributions in stellar activity sites would be improved with a closer timing of observations and higher signal to noise ratios in emission line data. (C) 2009 WILEY-VCH Verlag GmbH &Co. KGaA, Weinheim
dc.description.sponsorshipCommonwealth of Australia; OTKA [T48961, K68626]
dc.description.sponsorshipWe thank the Turkish Science Research Council (TUBITAK) and the Carter National Observatory of New Zealand for supporting the optical observations discussed this report. Mt. John University Observatory gave generous allocations of time, and its staff supported the data-collection, which was ably assisted by Volkan and Hicran Baki. The Compact Array at Narrabri NSW is part of the Australia Telescope, which is funded by the Commonwealth of Australia for operation as a National Facility managed by CSIRO. Dr. Gregory Tsarevsky provided greatly valued help and support during the microwave observations. K.O. acknowledges support from the research grants OTKA T48961 and K68626.
dc.identifier.doi10.1002/asna.200811193
dc.identifier.endpage365
dc.identifier.issn0004-6337
dc.identifier.issue4
dc.identifier.scopus2-s2.0-70350084955
dc.identifier.scopusqualityQ3
dc.identifier.startpage358
dc.identifier.urihttps://doi.org/10.1002/asna.200811193
dc.identifier.urihttps://hdl.handle.net/20.500.12428/22380
dc.identifier.volume330
dc.identifier.wosWOS:000266479600006
dc.identifier.wosqualityQ3
dc.indekslendigikaynakWeb of Science
dc.indekslendigikaynakScopus
dc.language.isoen
dc.publisherWiley-V C H Verlag Gmbh
dc.relation.ispartofAstronomische Nachrichten
dc.relation.publicationcategoryinfo:eu-repo/semantics/openAccess
dc.rightsinfo:eu-repo/semantics/closedAccess
dc.snmzKA_WoS_20250125
dc.subjectstars: activity
dc.subjectstars: chromospheres
dc.subjectstars: individual (AB Dor)
dc.subjectstarspots
dc.titleRecent observations of AB Dor and interpretation
dc.typeArticle

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