The Formation of Single and Binary Nuclei of Planetary Nebulae

Abstract

The present birthrate of binaries may be written as

$${d^3}v = 0.2M_1^{ - 2.5}{q^\alpha }d{M_1}d\log Adq{\text{ }}y{r^{ - 1}}$$

where M ₁ is the mass of the primary in M _⊙, 0 < q ≤1 - mass ratio of components, A - semimajor axis of the orbit in R _⊙. The Eq.(1) implies that all stars are born as binaries with 10 ≤ A/R _⊙≤ 10⁶, and that one binary with M ₁ ≥ 0.8M _⊙, is formed annually in the Galaxy. We study numerically evolutionary scenarii of binaries within abovementioned range of M ₁, A, q. As PN formation events we consider all ejections of common envelopes by close binaries and ejections of envelopes by red giants, after which one may expect a formation of a hot (T _e ≥ 30 000K) star, surrounded by a nebula. Altogether about 20 different single and binary cores of PN can be formed. Combining the scenarii data with the Eq. (1) one can estimate the birthrates of most numerous kinds of PNN (single and with main-sequence, white dwarf, giant and relativistic companions) listed in the Table.