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dc.contributor.authorAbraham, Z.
dc.contributor.authorFalceta-Gonçalves, D.
dc.contributor.authorBeaklini, P.P.B.
dc.identifier.citationAbraham , Z , Falceta-Gonçalves , D & Beaklini , P P B 2014 , ' η Carinae baby homunculus uncovered by ALMA ' , Astrophysical Journal , vol. 791 , no. 2 , 95 .
dc.identifier.otherPURE: 145685754
dc.identifier.otherPURE UUID: f8b19926-fe74-4a58-b7c3-6dc2a66bd28e
dc.identifier.otherScopus: 84905642724
dc.identifier.otherWOS: 000340028400022
dc.descriptionThis work was supported by the Brazilian agencies CAPES, CNPq, and FAPESP. D.F.G. thanks the European Research Council (ADG-2011 ECOGAL) and Brazilian agencies CNPq (No. 300382/2008-1), CAPES (No. 3400-13-1), and FAPESP (No. 2011/12909-8) for financial support.en
dc.description.abstractWe report observations of η Carinae obtained with ALMA in the continuum of 100, 230, 280, and 660 GHz in 2012 November, with a resolution that varied from 2.″88 to 0.″45 for the lower and higher frequencies, respectively. The source is not resolved, even at the highest frequency; its spectrum is characteristic of thermal bremsstrahlung of a compact source, but different from the spectrum of optically thin wind. The recombination lines H42α, He42α, H40α, He40α, H50β, H28α, He28α, H21α, and He21α were also detected, and their intensities reveal non-local thermodynamic equilibrium effects. We found that the line profiles could only be fit by an expanding shell of dense and ionized gas, which produces a slow shock in the surroundings of η Carinae. Combined with fittings to the continuum, we were able to constrain the shell size, radius, density, temperature, and velocity. The detection of the He recombination lines is compatible with the high-temperature gas and requires a high-energy ionizing photon flux, which must be provided by the companion star. The mass-loss rate and wind velocity, necessary to explain the formation of the shell, are compatible with an luminous blue variable eruption. The position, velocity, and physical parameters of the shell coincide with those of the Weigelt blobs. The dynamics found for the expanding shell correspond to matter ejected by η Carinae in 1941 in an event similar to that which formed the Little Homunculus; for that reason, we called the new ejecta the "Baby Homunculus."
dc.relation.ispartofAstrophysical Journalen
dc.rights© 2014. The American Astronomical Society. All rights reserved.en
dc.subjectCircumstellar matteren
dc.subjectStars: individual (Eta Carinae)en
dc.subjectStars: mass-lossen
dc.subjectStars: winds, outflowsen
dc.subjectQB Astronomyen
dc.subjectQC Physicsen
dc.titleη Carinae baby homunculus uncovered by ALMAen
dc.typeJournal articleen
dc.contributor.sponsorEuropean Research Councilen
dc.description.versionPublisher PDFen
dc.contributor.institutionUniversity of St Andrews. School of Physics and Astronomyen
dc.description.statusPeer revieweden

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