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Astron. Astrophys. 323, 775-780 (1997)

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Is the Sun located near the corotation circle?

Yu.N. Mishurov 1, I.A. Zenina 1, A.K. Dambis 2, A.M. Mel'nik 2 and A.S. Rastorguev 2

1 Space Research Department, Rostov State University, 5 Zorge, Rostov-on-Don, 344104, Russia
2 Sternberg Astronomical Institute, Moscow State University, University Avenue 13, Moscow, 119899, Russia

Received 11 April 1996 / Accepted 30 October 1996


The line-of-sight velocity field of Cepheids was analysed in terms of a disk galaxy model perturbed by spiral density waves in order to estimate the parameters of the galactic rotation curve and the free parameters of density waves. It was shown that: 1) the Sun is located near the corotation circle because the angular rotation velocity of the Galaxy [FORMULA] [FORMULA] [FORMULA] kpc-1 (Kerr & Lynden-Bell, 1986; Dambis, Mel'nik & Rastorguev, 1995) is close to that of the spiral pattern [FORMULA] [FORMULA] kpc-1 and the corotation radius [FORMULA] kpc (we adopt the galactocentric distance of the Sun [FORMULA] kpc); 2) the spiral pitch angle [FORMULA] ; 3) the Sun is at the spiral wave phase [FORMULA] ; 4) Oort's constant [FORMULA] [FORMULA] kpc-1 ; the second term in the expansion of the galactic rotation velocity is [FORMULA] [FORMULA] kpc-2.

Key words: Galaxy: kinematics and dynamics – structure – Cepheids

Send offprint requests to: Yu.N.Mishurov Table 2 is only available in electronic form at the CDS via anonymous ftp".

© European Southern Observatory (ESO) 1997

Online publication: May 26, 1998