AAS 205th Meeting, 9-13 January 2005
Session 98 High Mass Star Formation and Deeply Embedded Star Formation
Poster, Wednesday, January 12, 2005, 9:20am-6:30pm, Exhibit Hall

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[98.05] H2 Turbulence in Cepheus A

I. Cruz-Gonzalez (Instituto de Astronomia, UNAM, Mexico), D. Hiriart, L. Salas (Instituto de Astronomia, UNAM (Ensenada, B.C.), Mexico)

We present the radial velocity structure of the molecular hydrogen outflows associated to the star--forming region Cepheus A. This structure is derived from the Doppler shift of the H2 emission line v=1--0 line (2.122 \micron, \Delta \lambda=0.02 \micron) obtained by scanning Fabry--Pérot interferometry. The East and West regions of emission, called Cep~A~(E) and Cep~A~(W), show radial velocities in the range of -20 to 0~km~s-1 with respect to the molecular cloud. Cep~A~(W) shows an increasing velocity with position offset from the core indicating the existence of a possible accelerating mechanism. Cep~A~(E) has an almost constant mean radial velocity of -18~km~s-1 along the region although with a large dispersion in velocity, indicating the possibility of a turbulent outflow. A Mach disk found in Cep~A~(E) indicates that the molecular jet is driving this outflow. While in Cep~A~(W) smooth velocity gradients are in agreement with the view (Hartigan et al. 2000) that Cep~A~(W) may be a hot bubble driving C--shocks on the ambient medium. A wavelet transform analysis is used to obtain position and characteristic size of H2 clumps, the spatial average central velocity and velocity dispersion are used to study turbulence in the region. Both outflows have a complex spatial and velocity structure characteristic of a turbulent flow. Turbulence is found larger in Cep~A~(E) than in Cep~A~(W) and probably of a different nature. As the former shows a spectrum closer to the Kolmogorov case while the later is more virialized. We acknowledge support from CONACyT research grant 36574-E.

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Bulletin of the American Astronomical Society, 36 5
© 2004. The American Astronomical Society.