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Article: Simultaneous observations of variability at all atmospheric levels of V824 Arae (HD 155555)

TitleSimultaneous observations of variability at all atmospheric levels of V824 Arae (HD 155555)
Authors
KeywordsStars: Activity
Stars: Chromospheres
Stars: Coronae
Stars: Individual (V824 Arae)
Stars: Late-Type
Issue Date2001
PublisherUniversity of Chicago Press. The Journal's web site is located at http://www.journals.uchicago.edu/AJ/home.html
Citation
Astronomical Journal, 2001, v. 122 n. 1, p. 332-348 How to Cite?
AbstractWe conducted a multiwavelength campaign observing V824 Ara (HD 155555, G5 IV + KO IV-V) continuously throughout one complete orbital cycle (∼ 1.7 days) in early May of 1996. At the core of this campaign were observations using the GHRS on the Hubble Space Telescope (HST). In all, about 48,000 spectra, many in rapid readout mode, were obtained with the GHRS covering the C IV, Mg II, and Fe XXI wavelength regions at 11-15 separate phases. Simultaneous observations were made with the Extreme Ultraviolet Explorer (EUVE). Radio observations (3.5 and 6 cm) were conducted at the Australian Telescope, while ground-based visual spectroscopic and photometric observations were made at European Southern Observatory, Cerro Tololo Inter-American Observatory, the Anglo-Australian Telescope, and South African Astronomical Observatory. Additional ground-based observations were obtained before, during, and after the campaign. Our primary intent was to obtain a three-dimensional model of the atmosphere extending from the photosphere to the corona. Variability was clearly detected, including several flares observed in the HST, EUVE, and radio data. We present results from modeling the ultraviolet transition region lines using an anisotropic macroturbulence model. Previous studies of transition region lines in late-type active stars have used multiple Gaussians to fit the observed line profiles, adding broad components to account for the extended wings observed in several active systems, including V711 Tau (HR 1099). This broad component has been interpreted as arising from the continuous presence of microflaring. We demonstrate that anisotropic macroturbulence models can also explain the observed Mg II profiles.
Persistent Identifierhttp://hdl.handle.net/10722/174860
ISSN
2015 Impact Factor: 4.617
2015 SCImago Journal Rankings: 3.069
ISI Accession Number ID
References

 

DC FieldValueLanguage
dc.contributor.authorDempsey, RCen_US
dc.contributor.authorNeff, JEen_US
dc.contributor.authorLim, Jen_US
dc.date.accessioned2012-11-26T08:47:51Z-
dc.date.available2012-11-26T08:47:51Z-
dc.date.issued2001en_US
dc.identifier.citationAstronomical Journal, 2001, v. 122 n. 1, p. 332-348en_US
dc.identifier.issn0004-6256en_US
dc.identifier.urihttp://hdl.handle.net/10722/174860-
dc.description.abstractWe conducted a multiwavelength campaign observing V824 Ara (HD 155555, G5 IV + KO IV-V) continuously throughout one complete orbital cycle (∼ 1.7 days) in early May of 1996. At the core of this campaign were observations using the GHRS on the Hubble Space Telescope (HST). In all, about 48,000 spectra, many in rapid readout mode, were obtained with the GHRS covering the C IV, Mg II, and Fe XXI wavelength regions at 11-15 separate phases. Simultaneous observations were made with the Extreme Ultraviolet Explorer (EUVE). Radio observations (3.5 and 6 cm) were conducted at the Australian Telescope, while ground-based visual spectroscopic and photometric observations were made at European Southern Observatory, Cerro Tololo Inter-American Observatory, the Anglo-Australian Telescope, and South African Astronomical Observatory. Additional ground-based observations were obtained before, during, and after the campaign. Our primary intent was to obtain a three-dimensional model of the atmosphere extending from the photosphere to the corona. Variability was clearly detected, including several flares observed in the HST, EUVE, and radio data. We present results from modeling the ultraviolet transition region lines using an anisotropic macroturbulence model. Previous studies of transition region lines in late-type active stars have used multiple Gaussians to fit the observed line profiles, adding broad components to account for the extended wings observed in several active systems, including V711 Tau (HR 1099). This broad component has been interpreted as arising from the continuous presence of microflaring. We demonstrate that anisotropic macroturbulence models can also explain the observed Mg II profiles.en_US
dc.languageengen_US
dc.publisherUniversity of Chicago Press. The Journal's web site is located at http://www.journals.uchicago.edu/AJ/home.htmlen_US
dc.relation.ispartofAstronomical Journalen_US
dc.subjectStars: Activityen_US
dc.subjectStars: Chromospheresen_US
dc.subjectStars: Coronaeen_US
dc.subjectStars: Individual (V824 Arae)en_US
dc.subjectStars: Late-Typeen_US
dc.titleSimultaneous observations of variability at all atmospheric levels of V824 Arae (HD 155555)en_US
dc.typeArticleen_US
dc.identifier.emailLim, J: jjlim@hku.hken_US
dc.identifier.authorityLim, J=rp00745en_US
dc.description.naturelink_to_subscribed_fulltexten_US
dc.identifier.doi10.1086/321102en_US
dc.identifier.scopuseid_2-s2.0-0041083129en_US
dc.relation.referenceshttp://www.scopus.com/mlt/select.url?eid=2-s2.0-0041083129&selection=ref&src=s&origin=recordpageen_US
dc.identifier.volume122en_US
dc.identifier.issue1en_US
dc.identifier.spage332en_US
dc.identifier.epage348en_US
dc.identifier.isiWOS:000169943300029-
dc.publisher.placeUnited Statesen_US
dc.identifier.scopusauthoridDempsey, RC=7102259237en_US
dc.identifier.scopusauthoridNeff, JE=7202749112en_US
dc.identifier.scopusauthoridLim, J=7403453870en_US

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