Trigonometric Parallaxes and a Kinematically Adjusted Distance Scale for OB Associations

Details Trigonometric Parallaxes and a Kinematically Adjusted Distance Scale for OB Associations Trigonometric Parallaxes and a Kinematically Adjusted Distance Scale for OB Associations

Jan 2001

adsabs.harvard.edu/cgi-bin/nph-data_query?bibcode=2001astl...27...58d&link_type=abstract

Astronomy Letters, vol. 27, p. 58-64 (2001)

Astronomy and Astrophysics

Astronomy

32

Star Clusters And Associations, Stellar Dynamics

Scientific paper

By directly comparing the photometric distances of Blaha and Humphreys (1989) (BH) to OB associations and field stars with the corresponding Hipparcos trigonometric parallaxes, we show that the BH distance scale is overestimated, on average, by 10-20%. This result is independently corroborated by applying the rigorous statistical-parallax method and its simplified analog (finding a kinematically adjusted rotation-curve solution from radial velocities and proper motions) to a sample of OB associations. These two methods lead us to conclude that the BH distance scale for OB associations should be shrunk, on average, by 11 +/- 6 and 24 +/- 10 %, respectively. Kinematical parameters have been determined for the system of OB associations: u_0 = 8.2 +/- 1.3 km/s, v_0= 11.9 +/- 1.1 km/s, w_0 = 9.5 +/- 0.9 km/s, sigma_u = 8.2 +/- 1.1 km/s, sigma_v = 5.8 +/- 0.8 km/s, sigma_w = 5.0 +/- 0.8 km/s, Omega_0 = 29.1 +/- 1.0 km/s/kpc, (Omega_0)' = -4.57 +/- 0.20 km/s/kpc^2, and (Omega_0)'' = 1.32 +/- 0.14 km/s/kpc^3. The distance scale for OB associations reduced by 20% matches the short Cepheid distance scale (Berdnikov and Efremov 1985; Sitnik and Mel'nik 1996). Our results are a further argument for the short distance scale in the Universe.

Affiliated with

Also associated with

No associations

Rating

Trigonometric Parallaxes and a Kinematically Adjusted Distance Scale for OB Associations does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.

If you have personal experience with Trigonometric Parallaxes and a Kinematically Adjusted Distance Scale for OB Associations, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Trigonometric Parallaxes and a Kinematically Adjusted Distance Scale for OB Associations will most certainly appreciate the feedback.

Rate now

Comments { 0 }

Profile ID: LFWR-SCP-O-922948