Hostname: page-component-77c89778f8-vpsfw Total loading time: 0 Render date: 2024-07-18T14:25:24.006Z Has data issue: false hasContentIssue false

On the Problem of the Mechanism of the Origin of Stars in Stellar Associations

Published online by Cambridge University Press:  03 August 2017

V. A. Ambartsumian*
Affiliation:
Burakan Astrophysical Observatory Academy of Sciences of the Armenian S. S. R., Erevan, Armenian S. S. R., U. S. S. R.

Extract

Core share and HTML view are not available for this content. However, as you have access to this content, a full PDF is available via the ‘Save PDF’ action button.

Almost ten years have passed since the idea of stellar associations as nonstable stellar systems was formulated. The complex of observational data obtained during this time indicates that stars contained in the associations are young objects of some million years of age. We would like to stress here that this concerns both the O and T associations. It is also known that those O associations which could be sufficiently investigated in this respect, contain, as a rule, T Tauri type stars and are consequently T associations as well. There are, on the other hand, T associations which do not contain hot giants. But apparently the mechanisms of stellar formations must be similar in O and T associations. This means that any theory of stellar origin for a given type of association must permit variations, which will provide an explanation of the origin of stars in associations of other type.

Two hypotheses on the origin of stellar associations have been thus far discussed. One of them, suggested by the author at the initial stage of the idea about associations, supposes that each association has originated as a result of an expansion from a body or a system, the volume of which was initially very small. The dimensions of the latter was in any case less than one parsec. According to this point of view, these initial bodies (protostars) have either not been observed up to the present, or have not yet been identified with any known object. This point of view does not give any indication about a concrete mechanism of stellar origin, postponing its explanation to the time, when the earliest stages of the expansion of the association may be studied in detail.

Type
Part I: Empirical Studies of Velocity Fields in, and Related Structure of, the Interstellar Medium
Copyright
Copyright © American Physical Society 1958 

References

1 Ambartsumian, V. A., Stellar Evolution and Astrophysics (Erevan, U.S.S.R., 1947).Google Scholar

2 Oort, J. H., “Gas dynamics of cosmic clouds,” I. A. U. Symposium No. 2 (North-Holland Publishing Company, Ansterdam, The Netherlands, 1955), p. 147.Google Scholar

3 Oort, J. H. and Spitzer, L., Astrophys. J. 121, 6 (1955).CrossRefGoogle Scholar

4 Minkowski, R., Publs. Astron. Soc. Pacific 61, 151 (1949).CrossRefGoogle Scholar

5 Shajn, G. A. and Hase, V. Th., Atlas of Diffuse Nebulae (Moscow, U.S.S.R., 1952).Google Scholar

6 Morgan, , Strömgren, , and Johnson, , Astrophys. 121, 611 (1955).CrossRefGoogle Scholar

7 Markarian, B. E., Communs. Burakan Obs. No. 5 (1950).Google Scholar

8 Sharpless, S., Astrophys. J. 119, 334 (1954).CrossRefGoogle Scholar

9 Ambartsumian, V. A., Communs. Burakan Obs. No. 15 (1954).Google Scholar

10 Markarian, B. E., No. 11, 19 (1953).Google Scholar

11 Hopman, J. and Heidrich, K., Mitt. Sternwarte Wien 9, 57 (1956).Google Scholar

12 Menon, T. K., 1956, “A 21-cm investigation of the Orion region,” thesis, Harvard University.Google Scholar

13 Oberguggenberger, V., Z. Astrophys. 16, 323 (1938).Google Scholar

14 Fessenkov, V. G. and Rojkovsky, D. A., Astron. Zhur. 29, 397 (1952).Google Scholar

15 Martynov, D. Ya., Uchenye Zapiski Kazan. Gosudarst. Univ. im. V.I. Ul'yanova-Lenina 114, 89 (1954).Google Scholar

16 Markarian, B. E., No. 9 (1951).Google Scholar