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Detection of two new LBV stars.
In two exterior galaxies new luminous blue variable stars (LBV) were
observed. They are the most massive stars at an evolutionary stage just
before a supernova burst. In M33 galaxy it is the seventh LBV having a
luminosity of
~2x106L
,
mass )
(For contacts: S.N.Fabrika and
S.A.Pustilnik).
G89-14 - quaternary system with the lowest metallicity
By means of a speckle interferometry method with BTA telescope it was
detected that a sub-dwarf system G89-14 with [m/H]=-1.9 situated in a halo
of the Galaxy consists of four components (MA~0.67,
MB~0.24, MC~0.33, MD~0.22 solar masses)
and that it is a system with the lowest metallicity
among all known quaternary stars. It shows that the system was forming in
an environment with a low metal concentration. Orbital period ratio for the
quaternary system is P1:P2:P3=0.52:3000:650000 years, which points at a high
hierarchical organization and a stability of the system. Existence of such
objects proves systems with high multiplicity to be able to remain
throughout dynamic evolution for the time comparable to the age of the
Galaxy.
(For contacts: D.A.Rastegaev).
Fast deceleration of rotation of a magnetic star with a strong field HD
37776.
31 years of observations of the magnetic star HD 37776 resulted in detecting
deceleration of its axial rotation for 17.7±0.7s
(dP/P = 4.0x10-6 per year).
The star has a very strong magnetic field ( ~70-80 kGs on surface) of
complex configuration, its age is no more than 1 billion years. The star is
surrounded by a nebula. It is supposed that a magnetic deceleration is
present (at least in its outer layers), the deceleration is caused by loss
of angular momentum through a solar wind which is controlled by a magnetic
field. It is the first case of magnetic deceleration detection for a
chemically peculiar star on the main sequence.
In cooperation with Institute of Theoretical Physics and Astrophysics,
Astronomical Institute and Technical University (Czech), The University of
Tennessee (USA), Astronomical institute (Slovakia), Herzberg Institute of
Astrophysics (Canada), University of Zagreb (Croatia), Rojen National
Astronomical Observatory (Hungary).
(For contacts: I.I.Romanyuk).
Optical observations of an isolated neutron star.
Through international cooperation (Russia, Spain, Germany, South Africa,
Chili) observations of optical emission from a SWIFT event J195509+261406
had been carried out during three days. It was demonstrated that this event
was neither a classic gamma-ray burst nor a black hole in a binary system
nor a micro quasar. It corresponds more to a model of isolated neutron star
with abnormally strong magnetic field ~1015Gs (magnetar in
its active phase). A variability of optical emission of a soft
gamma-repeater is detected. It was shown that this event represents
a "bridge" in luminosity scale between abnormal X-ray pulsars and faint
isolated neutron stars.
In cooperation with international group of researchers
(coordinator A.Castro-Tirado, Spain).
(For contacts: T.A.Fatkhullin).
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