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A New Spectroscopic and Interferometric Study of the Young Stellar Object V645 CygAims. We present the results of high-resolution optical spectroscopy, low-resolution near-IR spectroscopy and near-infrared speckle interferometry of the massive young stellar object candidate V645 Cyg that were taken in order to refine its fundamental parameters and properties of its circumstellar envelope. Methods. Speckle interferometry in the H- and K-bands and an optical spectrum in the range 5200-6680 A with a spectral resolving power of R = 60000 were obtained at the 6 m telescope of the Russian Academy of Sciences. Another optical spectrum in the range 4300-10500 A with R = 79000 was obtained at the 3.6m CFHT. A low-resolution spectrum in the ranges 0.46-1.4 and 1.4-2.5 microns with a R approx. 800 and approx. 700, respectively, were obtained at the 3m Shain telescope of the Lick Observatory. Results. Using a new kinematic method based on non-linear modeling of the neutral hydrogen density profile in the direction toward the object, we suggest a new a distance D = 4.2+/-0.2 kpc. We also suggest a new estimate for the star's effective temperature, T(sub eff) approx. 25000 K. We have resolved the object in both H- and K-bands. Using a two-component ring fit, we derived a compact component size of 18 mas and 15 mas in the H- and K-band, respectively, which correspond to 37 and 33 AU at the new distance. Analysis of our and previously published data shows a approx. 2 mag drop of the near-infrared brightness of V645 Cyg in the beginning of the 1980 s. At the same time, the cometary nebular condensation N1 seems to fade in this wavelength range with respect to the N0 object, which represent the star with a nearly pole-on optically-thick disk and an optically-thin envelope. Conclusions. We conclude that V645 Cyg is a young massive main-sequence star, which recently emerged from its cocoon. and already passed the protostellar accretion stage. The presence of accretion is not necessary to account for the high observed luminosity of (2.6) x 10(exp 4) Solar Mass/yr. The receding part of a strong, mostly uniform outflow with a terminal velocity of approx.800 km/s is only blocked from view far from the star, where forbidden lines form. The near-infrared size of the source is consistent with the dust sublimation distance near this hot and luminous star and is the largest among young stellar objects observed interferometrically to-date.
Document ID
20090035631
Acquisition Source
Langley Research Center
Document Type
Reprint (Version printed in journal)
Authors
Miroshinichenko, A. S.
(Max-Planck-Inst. fuer Radioastronomie Bonn, Germany)
Hofmann, K.-H.
(Max-Planck-Inst. fuer Radioastronomie Bonn, Germany)
Schertl, D.
(Max-Planck-Inst. fuer Radioastronomie Bonn, Germany)
Weigelt, G.
(Max-Planck-Inst. fuer Radioastronomie Bonn, Germany)
Kraus, S.
(Max-Planck-Inst. fuer Radioastronomie Bonn, Germany)
Manset, N.
(CFHT Corp. Kamuela, HI, United States)
Balega, Y. Y.
(Special Astrophysical Observatory Nishnyi Archys, Russian Federation)
Klochkova, V. G.
(Special Astrophysical Observatory Nishnyi Archys, Russian Federation)
Rudy, R. J.
(Special Astrophysical Observatory Nishnyi Archys, Russian Federation)
Lynch, D. K.
(Special Astrophysical Observatory Nishnyi Archys, Russian Federation)
Mazuk, S.
(Special Astrophysical Observatory Nishnyi Archys, Russian Federation)
Venturini, C. C.
(Aerospace Corp. Los Angeles, CA, United States)
Grankin, K. N.
(Crimean Astrophysical Observatory Ukraine)
Puetter, R. C.
(California Univ., San Diego La Jolla, CA, United States)
Perry, R. B.
(NASA Langley Research Center Hampton, VA, United States)
Date Acquired
August 24, 2013
Publication Date
April 1, 2009
Publication Information
Publication: Astronomy & Astrophysics
Volume: 498
Issue: 1
Subject Category
Astrophysics
Report/Patent Number
LF99-7982
Funding Number(s)
WBS: WBS 581291.01.02.01
Distribution Limits
Public
Copyright
Other

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