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(Reference retrieved automatically from Web of Science through information on FAPESP grant and its corresponding number as mentioned in the publication by the authors.)

eta CARINAE BABY HOMUNCULUS UNCOVERED BY ALMA

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Author(s):
Abraham, Zulema [1] ; Falceta-Goncalves, Diego [2, 3] ; Beaklini, Pedro P. B. [1, 4]
Total Authors: 3
Affiliation:
[1] Univ Sao Paulo, Inst Astron Geofis & Ciencias Atmosfer, BR-05508900 Sao Paulo - Brazil
[2] Univ St Andrews, SUPA, Sch Phys & Astron, St Andrews KY16 9SS, Fife - Scotland
[3] Univ Sao Paulo, Escola Artes Ciencias & Humanidades, BR-03828000 Sao Paulo - Brazil
[4] IRAM, F-38406 St Martin Dheres - France
Total Affiliations: 4
Document type: Journal article
Source: ASTROPHYSICAL JOURNAL; v. 791, n. 2 AUG 20 2014.
Web of Science Citations: 8
Abstract

We report observations of. 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 H42 alpha, He42 alpha, H40 alpha, He40 alpha, H50 beta, H28 alpha, He28 alpha, H21 alpha, and He21 alpha 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. 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. 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.{''} (AU)

FAPESP's process: 11/12909-8 - Magnetic fields, turbulence and plasma effects in the intergalactic medium
Grantee:Diego Antonio Falceta Gonçalves
Support type: Regular Research Grants