Astronomy Letters, News-97


Our journal got the second MAIK/NAUKA award
for the best publication in 1998 !!!


MAIK/NAUKA commended by this award the papers by V.S.Imshennik and D.V.Popov "An Analytic Model for the Evolution of a Close Binary System of Neutron (Degenerate) Stars" (Astronomy Letters, 1998, v.24, p.251) and by A.G.Aksenov, E.A.Zabrodina, V.S.Imshennik, and D.K.Nadyozhin "A Hydrodynamic Two-Dimensional Model for an Asymmetric Explosion of Collapsing Supernovae with Rapid Initial Rotation" (Astronomy Letters, 1997, v.23, p.779).

The explosions of type-II supernovae are thought to be associated with gravitational collapse of the iron core in a massive star (M > 10 Mo), which takes place at a certain stage of its evolution. During the explosion, a neutron star or a black hole is formed, and an enormous amount of energy (of about 5 x 1053 erg/s) is released. However, calculations of the collapse show that virtually all the energy is carried away by neutrinos within the first seconds after the explosion, and that it is not possible to explain where the kinetic energy of the expanding envelope and the energy radiated away at optical and ultraviolet wavelengths (a total of about 1 x 1051 erg/s) come from in terms of the spherically symmetric model.

The authors of these papers suggested that the supernova-explosion mechanism could be associated with rapid rotation of the neutron star which forms during collapse. This mechanism was developed and tested by the authors in their series of papers under the common title "Rotational Explosion Mechanism for Collapsing Supernovae" (a total of six papers) which were published in (Soviet) Astronomy Letters in 1992-1998. The above two papers are the key papers of the series. The proposed explosion scenario assumes the following sequence of events:

  1. Collapse of the iron core in a massive star to produce a dynamically unstable, rapidly rotating neutron star.
  2. Breakup of the neutron star into fragments, in particular, the formation of a binary system of neutron stars.
  3. Gravitational radiation of the system and energy and angular-momentum losses as the two stars approach each other, which results in mass transfer and a mutual change in the stellar masses.
  4. Mass loss by one (low-mass) of the stars to a critical value of about 0.1 Mo and the subsequent explosion.
  5. The formation and expansion of a rapidly moving cloud of "iron" gas, which produces a shock wave and triggers a supernova explosion.
One side effect of such an explosion could be bursts of gamma-ray radiation, which can account for the so-called cosmic gamma-ray bursts, which are currently monitored and studied extensively worldwide.

Annual competitions for the best publication are held by MAIK/NAUKA since 1995 and involve more than 100 scientific journals. There are 5 first (main) and 50 second (small) awards. line
May 25, 1999