Dynamics and structure of open star clusters

Title:

Dynamics and structure of open star clusters

Creator:

Ruprecht, J.

Identifier:

https://cdk.lib.cas.cz/client/handle/uuid:7c419310-0878-4310-8e47-f5f33cd08081
uuid:7c419310-0878-4310-8e47-f5f33cd08081

Subject:

galactic plane and open star clusters

Type:

model:article and TEXT

Format:

bez média and svazek

Description:

In this paper, a theory of the causes of condensations i the central parts of open star clusters is developed, which are in the state of approximate statistical equilibrium. A method is proposed of establishing the mean diameter of star clusters. Owing to galactic rtation, clusters of central densities smaller than 4.5 solar masses/parsec^3 show some elongation in the direction of the galactic plane. Clusters of central densities larger than 0.5 solar masses/parsec^3 may, as a whole, be regarded as stationary and their state as statistically in equilibrium. Assuming Maxwell´s velocity distribution, stars from the central parts of the star clusters will, on account of the shorter relaxation time, tend to escape quicker than these from the border. The star clusters will therefore contract quicker around the centre than at the border. After the state of the cluster has become stationary its central part has a larger kinetic energy than the border parts, in spite of the fact that the star energies of various cluster regions adjust themselves. The paper derives a method of determining initial residual star velocities in the cluster. Today´s value of the residual velocity, together with the initial velocity, allow us to estimate the age of the star cluster. The theoretical results were applied to moving cluster Hyades. The age was estimated as 1.1 x 10^9 years. The theoretical flatness of the cluster 0.69 agrees well with the observed value of 0.07, given by van Bueren [19].

Language:

Czech

Rights:

http://creativecommons.org/publicdomain/mark/1.0/
policy:public

Coverage:

[257]-302

Source:

Publications of the Astronomical Institute of the Academy of Sciences of the Czech Republic | 1958 Volume:34-42 | Number:34-42

Harvested from:

CDK

Metadata only:

false