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dc.contributor.authorRoettenbacher, R. M.
dc.contributor.authorMonnier, J. D.
dc.contributor.authorKorhonen, H.
dc.contributor.authorAarnio, A. N.
dc.contributor.authorBaron, F.
dc.contributor.authorChe, X.
dc.contributor.authorHarmon, R. O.
dc.contributor.authorKővári, Zs.
dc.contributor.authorKraus, Stefan
dc.contributor.authorSchaefer, G. H.
dc.contributor.authorTorres, G.
dc.contributor.authorZhao, M.
dc.contributor.authorten Brummelaar, T. A.
dc.contributor.authorSturmann, J.
dc.contributor.authorSturmann, L.
dc.date.accessioned2016-02-24T09:19:36Z
dc.date.issued2016-05-04
dc.description.abstractSunspots are cool areas caused by strong surface magnetic fields inhibiting convection. Moreover, strong magnetic fields can alter the average atmospheric structure , degrading our ability to measure stellar masses and ages. Stars more active than the Sun have more and stronger dark spots than in the solar case, including on the rotational pole itself. Doppler imaging, which has so far produced the most detailed images of surface structures on other stars than the Sun, cannot always distinguish the hemisphere in which the starspots are located, especially in the equatorial region and if the data quality is not optimal . This leads to problems in investigating the north-south distribution of starspot active latitudes (those latitudes with more spot activity), which are crucial constraints of dynamo theory. Polar spots, inferred only from Doppler tomography, could plausibly be observational artifacts, casting some doubt on their very existence. Here we report imaging of the old, magnetically-active star ζ Andromedae using long-baseline infrared interferometry. In our data, a dark polar spot is seen in each of two epochs, while lower-latitude spot structures in both hemispheres do not persist between observations revealing global starspot asymmetries. The north-south symmetry of active latitudes observed on the Sun is absent on ζ And, which hosts global spot patterns that cannot be produced by solar-type dynamos.en_GB
dc.description.sponsorshipNational Science Foundation (NSF)en_GB
dc.description.sponsorshipHungarian Academy of Sciencesen_GB
dc.identifier.citationPublished online 04 May 2016en_GB
dc.identifier.doi10.1038/nature17444
dc.identifier.grantnumberAST-0908253en_GB
dc.identifier.grantnumberAST 1211129en_GB
dc.identifier.grantnumberAST-1311698en_GB
dc.identifier.grantnumberOTKA K-109276en_GB
dc.identifier.urihttp://hdl.handle.net/10871/20097
dc.language.isoenen_GB
dc.publisherNature Publishing Groupen_GB
dc.rights.embargoreasonPublisher policyen_GB
dc.titleNo Sun-like dynamo on the active star ζ Andromedae from starspot asymmetryen_GB
dc.typeArticleen_GB
dc.descriptionThis is the author accepted manuscript. The final version is available from Nature Publishing Group via the DOI in this record.
dc.identifier.journalNatureen_GB


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