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
DUMITRESCU^{1}, LUBOMIR
ILIEV^{2}, VALERIU TUDOSE^{1}

^{1}Astronomical
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
PRICOPI^{1}, VASILE
MIOC^{1},
MAGDA STAVINSCHI^{1}, MICHAEL BARBOSU^{2}

^{1}Astronomical
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

^{2}SUNY
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*
+B*r*^{2}. 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.