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Astron. Astrophys. 331, L53-L56 (1998)

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Letter to the Editor

Increase of emission and shell features in the spectrum of the FUor V1057 Cyg *

P. Petrov 1, 2, R. Duemmler 2, I. Ilyin 2 and I. Tuominen 2

1 Crimean Astrophysical Observatory, 334413 Nauchny, Crimea, Ukraine
2 Astronomy Division, University of Oulu, P.O. Box 333, FIN-90571 Oulu, Finland

Received 14 November 1997 / Accepted 6 January 1998


High-resolution échelle spectra of the FUor V1057 Cyg were taken during its minimum brightness in 1996-97. The spectra show the appearance of strong shell-components in the lines of low excitation, an increase of the splitting of the photospheric absorption lines, and the appearance of weak emission lines. It is argued that the mysterious line splitting of the absorption lines in the spectrum of V1057 Cyg, which has been interpreted as originating from an accretion disk, can be explained simply by the presence of central emission cores in the broad absorption lines. This emission spectrum of V1057 Cyg has increased in strength relative to the continuum as the star has faded.

Key words: (stars:) circumstellar matter – stars: individual: V1057 Cyg – stars: pre – main sequence – accretion disks – FUors

* Based on observations obtained at the 2.56m Nordic Optical Telescope, Roque de Los Muchachos Observatory, La Palma/Spain.

Send offprint requests to: P. Petrov (e-mail: Peter.Petrov@Oulu.Fi)

© European Southern Observatory (ESO) 1998

Online publication: March 3, 1998