Discovery of a Young Stellar-Wind Shell in Cygnus X

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Session 58 -- Outflows and the Low Mass IMF
Oral presentation, Thursday, January 13, 10:15-11:45, Salon V Room (Crystal Gateway)

[58.01] Discovery of a Young Stellar-Wind Shell in Cygnus X

L.A. Higgs (NRC/DRAO), H.J. Wendker (Hamburg), T.L. Landecker (NRC/DRAO) ()

A small ring-like radio source (G 79.29+0.46) has been discovered in the Cygnus X region from observations made with the DRAO Synthesis Telescope. The shell, $\sim 4^\prime$ in diameter, has a flux density of $\sim 550$ mJy at 1.42 GHz. Observations at three frequencies (1.49, 4.86 and 8.44 GHz) with the VLA have confirmed that the shell source is thermal in nature. A central radio source with a radio spectrum indicative of mass outflow was also detected. A heavily reddened optical counterpart of the latter has been found. A quick-look optical spectrum of this star (m$_R \sim 15.4^m$) in the 550 - 750 nm region shows only a heavily reddened continuum and a strong H$\alpha$ emission line. Extended wings of this line correspond to a wind velocity of $\sim 1400$ km s$^{-1}$. Observations at DRAO of the 21-cm line of atomic hydrogen indicate accelerated atomic gas associated with the ionized shell, and a shell expansion velocity of $\sim 70$ km s$^{-1}$. IRAS infrared data show the presence of warm dust ($T \sim 65$ K) in the ionized shell, and hotter dust ($T > 125$ K) associated with the central star and its wind. A consideration of all the observational data suggests a very luminous central star ($M_b \sim -11^m$) at a distance of $\sim 2$ kpc, having an effective temperature of $\sim 25,000$ K. It is suggested that it may be a member of the Luminous Blue Variable class. The age of the shell, having a mass of $\sim 15$ M$_\odot$, is estimated to be $\sim 10^4$ yr.

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