Analysis of a fragmenting sunspot using hinode observations

We employ high-resolution filtergrams and polarimetric measurements from Hinode to follow the evolution of a sunspot for eight days starting on 2007 June 28. The imaging data were corrected for intensity gradients, projection effects, and instrumental stray light prior to the analysis. The observati...

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Autores: Louis, Rohan E., Ravindra, B., Mathew, Shibu K., Bellot Rubio, Luis R., Raja Bayanna, A., Venkataraman, P.
Tipo de recurso: artículo
Estado:Versión aceptada para publicación
Fecha de publicación:2012
País:España
Institución:Consejo Superior de Investigaciones Científicas (CSIC)
Repositorio:DIGITAL.CSIC. Repositorio Institucional del CSIC
OAI Identifier:oai:digital.csic.es:10261/414385
Acceso en línea:http://hdl.handle.net/10261/414385
Access Level:acceso abierto
Palabra clave:Sun: photosphere
Sunspots
Sun: surface magnetism
Echniques: photometric
Echniques: polarimetric
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spelling Analysis of a fragmenting sunspot using hinode observationsLouis, Rohan E.Ravindra, B.Mathew, Shibu K.Bellot Rubio, Luis R.Raja Bayanna, A.Venkataraman, P.Sun: photosphereSunspotsSun: surface magnetismEchniques: photometricEchniques: polarimetricWe employ high-resolution filtergrams and polarimetric measurements from Hinode to follow the evolution of a sunspot for eight days starting on 2007 June 28. The imaging data were corrected for intensity gradients, projection effects, and instrumental stray light prior to the analysis. The observations show the formation of a light bridge at one corner of the sunspot by a slow intrusion of neighboring penumbral filaments. This divided the umbra into two individual umbral cores. During the light bridge formation, there was a steep increase in its intensity from 0.28 to 0.7 I QS in nearly 4hr, followed by a gradual increase to quiet-Sun (QS) values in 13hr. This increase in intensity was accompanied by a large reduction in the field strength from 1800G to 300G. The smaller umbral core gradually broke away from the parent sunspot nearly twodays after the formation of the light bridge, rendering the parent spot without a penumbra at the location of fragmentation. The penumbra in the fragment disappeared first within 34hr, followed by the fragment whose area decayed exponentially with a time constant of 22hr. In comparison, the parent sunspot area followed a linear decay rate of 0.94Mm2hr-1. The depleted penumbra in the parent sunspot regenerated when the inclination of the magnetic field at the penumbra-QS boundary became within 40° from being completely horizontal and this occurred near the end of the fragment's lifetime. After the disappearance of the fragment, another light bridge formed in the parent which had similar properties as the fragmenting one, but did not divide the sunspot. The significant weakening in field strength in the light bridge along with the presence of granulation is suggestive of strong convection in the sunspot, which might have triggered the expulsion and fragmentation of the smaller spot. Although the presence of QS photospheric conditions in sunspot umbrae could be a necessary condition for fragmentation, it is not a sufficient one. © 2012 The American Astronomical Society. All rights reserved.We sincerely thank the Hinode team for providing the data used in this paper. Hinode is a Japanese mission developed and launched by ISAS/JAXA, with NAOJ as domestic partner and NASA and STFC (UK) as international partners. It is operated by these agencies in cooperation with ESA and NSC (Norway). Hinode SOT/SP Inversions were conducted at NCAR under the framework of the Community Spectro-polarimtetric Analysis Center. We thank the anonymous referee for useful comments and suggestions. R.E.L. is grateful for the financial support from the German Science Foundation (DFG) under grant DE 9422. Our work has been partially funded by the Spanish MICINN through projects AYA2009-14105-C06-06 and by Junta de Andaluc´ıa through project P07-TEP-2687.Peer reviewedIOP PublishingJapan Aerospace Exploration AgencyInstitute of Space and Astronautical Science (Japan)NASAScience and Technology Facilities Council (UK)European Space AgencyNorwegian Seafood FederationGerman Research FoundationMinisterio de Ciencia e Innovación (España)Junta de AndalucíaConsejo Superior de Investigaciones Científicas [https://ror.org/02gfc7t72]202620262012info:eu-repo/semantics/articlehttp://purl.org/coar/resource_type/c_6501Postprintinfo:eu-repo/semantics/acceptedVersionhttp://hdl.handle.net/10261/414385reponame:DIGITAL.CSIC. Repositorio Institucional del CSICinstname:Consejo Superior de Investigaciones Científicas (CSIC)Inglés#PLACEHOLDER_PARENT_METADATA_VALUE#info:eu-repo/grantAgreement/MICINN//AYA2009-14105-C06-06http://dx.doi.org/10.1088/0004-637X/755/1/16Síinfo:eu-repo/semantics/openAccessoai:digital.csic.es:10261/4143852026-05-22T06:33:51Z
dc.title.none.fl_str_mv Analysis of a fragmenting sunspot using hinode observations
title Analysis of a fragmenting sunspot using hinode observations
spellingShingle Analysis of a fragmenting sunspot using hinode observations
Louis, Rohan E.
Sun: photosphere
Sunspots
Sun: surface magnetism
Echniques: photometric
Echniques: polarimetric
title_short Analysis of a fragmenting sunspot using hinode observations
title_full Analysis of a fragmenting sunspot using hinode observations
title_fullStr Analysis of a fragmenting sunspot using hinode observations
title_full_unstemmed Analysis of a fragmenting sunspot using hinode observations
title_sort Analysis of a fragmenting sunspot using hinode observations
dc.creator.none.fl_str_mv Louis, Rohan E.
Ravindra, B.
Mathew, Shibu K.
Bellot Rubio, Luis R.
Raja Bayanna, A.
Venkataraman, P.
author Louis, Rohan E.
author_facet Louis, Rohan E.
Ravindra, B.
Mathew, Shibu K.
Bellot Rubio, Luis R.
Raja Bayanna, A.
Venkataraman, P.
author_role author
author2 Ravindra, B.
Mathew, Shibu K.
Bellot Rubio, Luis R.
Raja Bayanna, A.
Venkataraman, P.
author2_role author
author
author
author
author
dc.contributor.none.fl_str_mv Japan Aerospace Exploration Agency
Institute of Space and Astronautical Science (Japan)
NASA
Science and Technology Facilities Council (UK)
European Space Agency
Norwegian Seafood Federation
German Research Foundation
Ministerio de Ciencia e Innovación (España)
Junta de Andalucía
Consejo Superior de Investigaciones Científicas [https://ror.org/02gfc7t72]
dc.subject.none.fl_str_mv Sun: photosphere
Sunspots
Sun: surface magnetism
Echniques: photometric
Echniques: polarimetric
topic Sun: photosphere
Sunspots
Sun: surface magnetism
Echniques: photometric
Echniques: polarimetric
description We employ high-resolution filtergrams and polarimetric measurements from Hinode to follow the evolution of a sunspot for eight days starting on 2007 June 28. The imaging data were corrected for intensity gradients, projection effects, and instrumental stray light prior to the analysis. The observations show the formation of a light bridge at one corner of the sunspot by a slow intrusion of neighboring penumbral filaments. This divided the umbra into two individual umbral cores. During the light bridge formation, there was a steep increase in its intensity from 0.28 to 0.7 I QS in nearly 4hr, followed by a gradual increase to quiet-Sun (QS) values in 13hr. This increase in intensity was accompanied by a large reduction in the field strength from 1800G to 300G. The smaller umbral core gradually broke away from the parent sunspot nearly twodays after the formation of the light bridge, rendering the parent spot without a penumbra at the location of fragmentation. The penumbra in the fragment disappeared first within 34hr, followed by the fragment whose area decayed exponentially with a time constant of 22hr. In comparison, the parent sunspot area followed a linear decay rate of 0.94Mm2hr-1. The depleted penumbra in the parent sunspot regenerated when the inclination of the magnetic field at the penumbra-QS boundary became within 40° from being completely horizontal and this occurred near the end of the fragment's lifetime. After the disappearance of the fragment, another light bridge formed in the parent which had similar properties as the fragmenting one, but did not divide the sunspot. The significant weakening in field strength in the light bridge along with the presence of granulation is suggestive of strong convection in the sunspot, which might have triggered the expulsion and fragmentation of the smaller spot. Although the presence of QS photospheric conditions in sunspot umbrae could be a necessary condition for fragmentation, it is not a sufficient one. © 2012 The American Astronomical Society. All rights reserved.
publishDate 2012
dc.date.none.fl_str_mv 2012
2026
2026
dc.type.none.fl_str_mv info:eu-repo/semantics/article
http://purl.org/coar/resource_type/c_6501
Postprint
info:eu-repo/semantics/acceptedVersion
format article
status_str acceptedVersion
dc.identifier.none.fl_str_mv http://hdl.handle.net/10261/414385
url http://hdl.handle.net/10261/414385
dc.language.none.fl_str_mv Inglés
language_invalid_str_mv Inglés
dc.relation.none.fl_str_mv #PLACEHOLDER_PARENT_METADATA_VALUE#
info:eu-repo/grantAgreement/MICINN//AYA2009-14105-C06-06
http://dx.doi.org/10.1088/0004-637X/755/1/16
Sí
dc.rights.none.fl_str_mv info:eu-repo/semantics/openAccess
eu_rights_str_mv openAccess
dc.publisher.none.fl_str_mv IOP Publishing
publisher.none.fl_str_mv IOP Publishing
dc.source.none.fl_str_mv reponame:DIGITAL.CSIC. Repositorio Institucional del CSIC
instname:Consejo Superior de Investigaciones Científicas (CSIC)
instname_str Consejo Superior de Investigaciones Científicas (CSIC)
reponame_str DIGITAL.CSIC. Repositorio Institucional del CSIC
collection DIGITAL.CSIC. Repositorio Institucional del CSIC
repository.name.fl_str_mv
repository.mail.fl_str_mv
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