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The kinematics of carbon stars in the large and small magellanic clouds

University of British Columbia

Radial velocities were determined for a sample of carbon star spectra. These carbon stars were located in the Large and Small Magellanic Clouds and were listed in the catalogues of Westerlund, Olander, Richer and Crabtree (1978), Blanco, McCarthy and Blanco (1980) and Sanduleak and Philip (1977). Rotation curves based upon the derived radial velocities indicated that the LMC rotates like a solid body. The velocity gradient of the carbon stars along the major axis was found to be 10.4 km/sec/deg. For circular orbits, this placed a lower mass limit of 6.0X109 Mo when employing a disk-shaped model of the LMC. When carbon stars were compared with other stellar populations in the LMC taken from the catalogue of Feitzinger and Weiss (1979) an increase of velocity gradient along the major axis was found to correlate with a decrease in object age. This was interpreted as an increase in orbital eccentricity with object age which agreed well with previous similar findings for our own galaxy (Eggen, Lynden-Bell, Sandage 1962). The velocity dispersions of the Blanco, McCarthy and Blanco Bar field in the SMC and the Bar West field in the LMC were also compared. The higher radial velocity dispersion of the SMC field was attributed to the higher inclination angle of the SMC and the possibility that the SMC field contained stars which were participating in streaming motions from opposite ends of the Bar.

Text

2010-04-20

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http://hdl.handle.net/2429/23955

Astronomy

University of British Columbia

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