THE DEFLECTION OF LIGHT IN THE DYNAMIC THEORY OF GRAVITY
IOANNIS IRAKLIS HARANAS
Department of Physics and Astronomy
E-mail:
ioannis@yorku.ca
Abstract. In a new theory
of gravity called the dynamic theory,
which is
derived from thermodymical principles in a five-dimensional
space, the
deflection of a light signal is calculated and compared to that of
general
relativity. This is achieved by using the dynamic
gravity line element
which is
the usual four-dimensional space-time element of Newtonian gravity
modified by
a negative inverse radial
exponential term. The dynamic theory of
gravity
predicts this modification of the original Newtonian potential by this
exponential term.
Key words: dynamic theory of gravity – thermodynamical delay – general relativity.
COLORS AND HST MORPHOLOGY OF EXTREMELY RED GALAXIES AT z > 1
NEDELIA
ANTONIA
POPESCU, MARIAN
DORU
ŞURAN
Astronomical
Institute of the
Str.
Cuţitul de
Argint 5, RO-040557 Bucharest, Romania
E-mails:
delia@aira.astro.ro, suran@aira.astro.ro
Abstract. Rich samples of
Extremely Red Objects (EROs) are being
determined
in the fields RX J0848.6+4453 (z =
1.273) and 3C210 (z = 1.169),
using
optical and near infrared photometric data (Stanford et al. 2002).
These data
are combined with HST morphological data (Stanford et al. 2002),
in
order to
discriminate between the two main classes of galaxies that form the
EROs
population: old, passive evolved ellipticals and dusty star forming
galaxies.
We study the K-band galaxy number
counts, the (I–K) and (J–K) color
distributions, the surface
density and the radial density profiles for EROs
and for the entire
sample of
galaxies in the mentioned fields. A 5 times increased surface density
of EROs,
selected with different multi-color criteria, is
observed in comparison
with
the density of such objects in the general field. The presence of an
overdensity of galaxies with red colors in the field of the
3C210 radio
galaxy,
representing a possible cluster of galaxies, is revealed.
Key words: cosmology – elliptical galaxies – extremely red objects.
THE DISTRIBUTION FUNCTION OF THE STARS VELOCITIES IN THE NEIGHBOURHOOD OF THE SUN
ADINA IONESCU
Faculty
of Mathematics,
Str.
Academiei 14,
E-mail:
adi_2301@ yahoo.com
Abstract. The distribution
function of the stars velocities and
its
development in Gram-Charlier series is deduced for stars situated in
various
volume
elements centered in the Sun. The study made in the system of
coordinates in which the velocity components are independent has shown
that the
value
of the excess coefficient increases at once with the increase of
the
volume element and, implicitly, with the number of stars from the
selection,
due to the
statistical non-homogeneities of the stellar populations
studied.
Key words: star velocity – distribution function – solar neighbourhood.
PHOTOMETRIC OBSERVATIONS OF THE ECLIPSING BINARY V376 AND
ALEXANDRU
DUMITRESCU1, LUBOMIR
ILIEV2, VALERIU TUDOSE1
1Astronomical
Institute of the
Str.
Cuţitul de
Argint 5, RO-040557, Bucharest, Romania
E-mail:
alex@aira.astro.ro, vtudose@aira.astro.ro
2
Institute of Astronomy of the
72
Tsarigradsko Shosse, BG-1784, Sofia, Bulgaria
E-mail:
liliev@astro.bas.bg
Abstract. We present
ground-based photoelectric observations of
the newly
discovered eclipsing binary V376 And. The observations were
carried out
at
Bucharest Observatory (
a new ephemeris
are
presented.
Key words: photoelectric photometry – variable stars – eclipsing binary systems – V376 And.
SOLAR CORONAL ACTIVE STRUCTURES. THEORETICAL APPROACH AND INSTRUMENTATION
ADRIAN SABIN POPESCU
Astronomical
Institute of the
Str.
Cuţitul de
Argint 5, RO-040557 Bucharest, Romania
E-mail:
sabinp@aira.astro.ro
Abstract. We propose a new
method for the investigation of active
phenomena
in the Sun. We use the newest methods (self-similar particle
distribution,
wavelet transformation, etc.) in our effort to understand the physics
that
stands behind spatial and temporal evolution of the active
phenomena
from the
solar corona (e.g., apparition and evolution of eruptions, eruptive
prominences, “helmet”-type prominences). By using the
polarization
theory and a
theory originating in the O spectral-type stellar objects atmosphere
description, we try to find the number of structures
(“blobs”) that are
present
at any instant in the solar corona (Brown et al. 1995). This number can
prove
to be a new mean of description and
prediction of the solar activity
evolution
through the solar cycle.
Key words: solar corona – polarization – active phenomena.
THE TWO-BODY PROBLEM IN THE POINT-MASS APPROXIMATION FIELD. V. GLOBAL FLOW
DUMITRU
PRICOPI1, VASILE
MIOC1,
MAGDA STAVINSCHI1, MICHAEL BARBOSU2
1Astronomical
Institute of the
Str.
Cuţitul de
Argint 5, RO-040557 Bucharest, Romania
E-mails:
dpricopi@aira.astro.ro, vmioc@aira.astro.ro, magda@aira.astro.ro
2SUNY Brockport, Department of Mathematics
E-mail:
mbarbosu@brockport.edu
Abstract.
The only fields for
which the correctness of the point-mass representation (
by potentials of the form A/r
+Br2. After tackling
various details of the two-body problem in such a field (collision,
escape,
equilibria, symmetries),
we complete the study by describing the global
flow
for all possible values of A and
nonzero B, and of the energy level
and angular momentum. We
find a rich set of phase (and physical)
orbits, with
many “exotic” features.
Key words: celestial mechanics – two-body problem – point-mass approximation.
SYMMETRIES IN THE POPOVICI-MANEV PHOTOGRAVITATIONAL FIELD
MIRA-CRISTIANA ANISIU 1, VASILE
MIOC 2
1 T. Popoviciu Institute of Numerical Analysis
C.
P. 68,
RO-400110 Cluj-Napoca, Romania
E-mail:
mira@math.ubbcluj.ro
2
Astronomical Institute of the
Str.
Cuţitul de
Argint 5, RO-040557 Bucharest, Romania
E-mail:
vmioc@aira.astro.ro
Abstract. The
Popovici-Manev photogravitational field is
generated by a
Manev-type attraction force and the repelling radiative force
considered by
Constantin Popovici. The equations of the two-body problem in this
field are
written as a system of first-order ODE, and
the symmetries of the
system are
displayed. It is proved that the group of symmetries of the problem in
either
Cartesian or polar coordinates
is (a) a subgroup (with four elements)
of the
group of symmetries (with eight elements) of the two-body problem
associated to
a quasihomogeneous
potential; (b) isomorphic to Klein’s group. These
properties
hold also for collision-blow-up and infinity-blow-up McGehee-type
coordinates.
If we
apply Levi-Civita regularizing transformations, the vector field
admits a
group of symmetries with eight elements, but its subgroup which is
physically
meaningful is again isomorphic to Klein’s group.
Key words: celestial mechanics – photogravitational models – symmetries.
THE GENERALIZED UNIVERSAL KEPLER’S EQUATION AND THE HOMOTOPY CONTINUATION METHOD
MOHAMED
ADEL SHARAF 1,
MONA ABDULLAH
BANAJAH 2, AISHA aBDU AL-SHAARY 2
1
Department of Astronomy, Faculty of
Science,
Jeddah,
Saudi
Arabia
E-mail:
sharaf_adel@hotmail.com
2
Department of Mathematics,
Abstract. We develop an
iterative method of arbitrary positive
convergence
order to solve the generalized universal Kepler’s equation The method
is
of
dynamic nature in the sense that, on going from one iterative scheme to
the
subsequent one, only additional instruction is needed. Moreover, the
method
does not need any a priori knowledge of the initial guess, a property
that
avoids the critical situations of divergent and very slowly convergent
solutions
that can appear in other numerical methods depending on
initial
guess. The computational package for digital implementation of the
method is
given and
applied to some cases.
Key words: celestial mechanics – Kepler’s equation – iterative methods.
NOTE
ABOUT THE TRANSIT
OF MERCURY ON
7 MAY 2003
OBSERVED IN
RADU
POPESCU, ALIN NEDELCU,
OCTAVIAN BĂDESCU,
PETRE
POPESCU
Astronomical
Institute of the
Str.
Cuţitul de
Argint 5, RO-040557 Bucharest, Romania
E-mail: [pradu, nedelcu, octavian, petre]@aira.astro.ro
Abstract. The transit of a
planet across the solar disk can be
thought as a
planetary eclipse. An observer from the Earth can see only transits
of
Mercury
and Venus. There are 13 transits of Mercury each century, on average.
We
observed in
a Meade
telescope endowed with a CCD camera. We determined the contacts and the
daytime
turbulence in the area.
Key words: Mercury’s transit – CCD observations.