EDP Sciences
Free access
Volume 436, Number 3, June IV 2005
Page(s) 945 - 952
Section Interstellar and circumstellar matter
DOI http://dx.doi.org/10.1051/0004-6361:20052835

A&A 436, 945-952 (2005)
DOI: 10.1051/0004-6361:20052835

Time variations of the narrow Fe II and H I spectral emission lines from the close vicinity of $\eta$ Carinae during the spectral event of 2003

H. Hartman1, A. Damineli2, S. Johansson1 and V. S. Letokhov3, 1

1  Lund Observatory, Lund University, PO Box 43, 22100, Lund, Sweden
    e-mail: henrik.hartman@astro.lu.se
2  Instituto de Astronomia, Geoffisica e Ciencias Atmosfericas, University of Sao Paolo, Rua do Matao 1226, 05508-900 Sao Paulo, Brazil
3  Institute of Spectroscopy, Russian Academy of Sciences, Troitsk, Moscow region, 142190, Russia

(Received 7 February 2005 / Accepted 9 March 2005 )

The spectrum of Eta Carinae and its ejecta shows slow variations over a period of 5.5 years. However, the spectrum changes drastically on a time scale of days once every period called the "spectral event". We report on variations in the narrow emission line spectrum of gas condensations (the Weigelt blobs) close to the central star during a spectral event. The rapid changes in the stellar radiation field illuminating the blobs make the blobs a natural astrophysical laboratory to study atomic photoprocesses. The different responses of the HI Paschen lines, fluorescent $\langle$ $\ion{Fe}{ii}$$\rangle$ lines and forbidden [ $\ion{Fe}{ii}$] lines allow us to identify the processes and estimate physical conditions in the blobs. This paper is based on observations from the Pico dos Dias Observatory (LNA/Brazil) during the previous event in June 2003. tomic processes - radiation mechanisms: non-thermal - ISM: $\ion{H}{ii}$ regions - stars: individual: Eta Carinae

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