**EXTREMELY RED OBJECTS**
**AROUND THE RADIO-LOUD QUASAR B2 1335+28**

NEDELIA ANTONIA POPESCU, MARIAN DORU ?URAN

*Astronomical Institute of the Romanian Academy*

*Str. Cu?itul de Argint 5, RO-75212 Bucharest, Romania*

*E-mail: delia@aira.astro.ro, suran@aira.astro.ro*

*Abstract*. Using the optical and near infrared photometrical
data for the objects in the field of the radio-loud quasar B2 1335+28,
at redshift *z* = 1.086 (Tanaka et al. 2000), we determine the sample
of the Extremely Red Objects (EROs) in this field. We analyze the *K*-band
galaxy number counts, the colors distributions, the surface density and
the radial density profiles for the entire sample of galaxies and for these
special objects, searching for radial trends and features of clustering.
In the studied field is observed a 3 times increased surface density of
EROs, selected with different single-color criteria, in comparison with
the density of such objects in the general field. This result confirms
the presence of an overdensity of galaxies with red colors in the neighbourhood
of the quasar, representing a cluster of galaxies.
*Key words*: cosmology color evolution of galaxies extremely
red objects.

**SAKHAROV'S TEMPERATURE LIMIT**
**IN A MODIFIED SCHWARZSCHILD METRIC**

IOANNIS IRAKLIS HARANAS

*Department of Physics and Astronomy*

*York University, Toronto, Ontario, Canada*

*E-mail: ioannis@yorku.ca*

*Abstract*. In this paper we are going to examine the effect,
if any exists, that a modification of the Schwarzschild metric by a lambda
term could have on the so-called Sakharovs upper temperature limit. Its
known that Sakharovs limit is the maximum possible black-body temperature
that can occur in our universe.
*Key words*: cosmology Schwarzschild metric cosmological constant
Sakharov's limit.

**A SOLAR ACTIVITY FORECAST:**
**CYCLES 2326**

MIROSLAV MIKULECKÝ ^{1}, JAROSLAV STRETÍK ^{2}

^{2}* Institute of Preventive and Clinical Medicine*

*Bratislava, Slovak Republic*

*E-mail: mikuleky@upkm.sk*

^{2}* Geophysical Institute of the Academy of Sciences of
the Czech Republic*

*Prague, Czech Republic*

*E-mail: jstr@ig.cas.cz*

*Abstract*. Increasing interest in putative effects of the changing
solar activity on the Earth including biomedical and sociological events
actualizes the need for forecasting its behaviour in the future. The authors
demonstrate an inferential statistical way of forecasting sunspot relative
numbers four decades ahead. Their prediction for 19611995, based on the
15001960 data and confronted with the known observations in this interval,
was better than that based on 19101960, 17491960, and 18491960 data.
The proper forecast for 19972040 was therefore constructed from the 15001996
data.
*Key words*: sunspot forecast inferential statistics.

**SYMMETRIES IN THE
ANISOTROPIC**
**KEPLER PROBLEM**

VASILE MIOC

*Astronomical Institute of the Romanian Academy*

*Str. Cu?itul de Argint 5, RO-75212 Bucharest, Romania*

*E-mail: vmioc@aira.astro.ro*

*Abstract*. The two-body problem associated to an anisotropic
Newtonian-type potential function is being considered. We point out the
complex symmetries that feature this problem. Such symmetries, expressed
in standard polar coordinates, are recovered for McGehee-type coordinates
of both collision-blow-up kind and infinity-blow-up kind. They form isomorphic
commutative groups endowed with an idempotent structure. Expressed in Levi-Civita's
coordinates, the problem exhibits a larger group of symmetries, also commutative
and endowed with an idempotent structure.
*Key words*: celestial mechanics anisotropy symmetries.

**THE DARK MATTER PERTURBATION**
**OF THE TWO-BODY PROBLEM**

C?T?LIN CUCU-DUMITRESCU, DAN SELARU

*Institute for Space Sciences*

*Str. Mendeleev 21-25, Bucharest, Romania*

*E-mail: cucudumitrescu@yahoo.com*

*Abstract*. The notion of WIMPs (Weakly Interacting Massive Particles)
is used in modern Physics to define a class of particles, which do not
interact electromagnetically, but only gravitationally. WIMPs can be found
in the neighbourhood of a massive celestial body (star, planet), forming
a cloud of low-density matter (dark matter), which can be modeled as a
continuous medium. In such a mechanical system, the motion of a test particle
is perturbed by the *interior potential* of the WIMP cloud. The first
problem we focused on is the possibility of obtaining a particular type
of perturbation due to the WIMP cloud, in order to explain some corrections
of the *universal law of attraction*. The well-known Maneff correction
(for the motion of Mercury around Sun) can be obtained in this way, if
we admit the presence of a certain low-density cloud in the vicinity of
Mercury's orbit. The main issue of this paper is the description of the
motion of a test particle around a massive celestial body surrounded by
a spherical, uniformly dense WIMP cloud. We obtained two forms of first
order solution, taking the density of the cloud as a small parameter; the
first form is clearly intuitive and the second one is proper for the numerical
investigations of close approach orbits.
*Key words*: celestial mechanics dark matter perturbed two-body
problem canonical transformations.

**EQUILIBRIA OF CONSTANTIN
POPOVICI'S**
**PHOTOGRAVITATIONAL MODEL REVISITED**

VASILE MIOC

*Astronomical Institute of the Romanian Academy*

*Str. Cu?itul de Argint 5, RO-75212 Bucharest, Romania*

*E-mail: vmioc@aira.astro.ro*

*Abstract*. The equilibria of the two-body problem associated
to Constantin Popovici's photogravitational model are tackled again. We
consider the motion in the infinity-blow-up coordinates provided by McGehee-type
transformations. Then we study the vector field expressed in collision-regularizing
Levi-Civita coordinates. This new framework provides the same location
of the equilibria and the same information about their nature as the previous
approaches.
*Key words*: celestial mechanics photogravitational fields
qualitative analysis equilibria.

**ACCURATE POSITIONS
FOR THE ASTEROID**
**433 EROS IN 19351938 AND 19721975**

GHEORGHE BOC?A, CONSTANTIN TELEANU

*Astronomical Institute of the Romanian Academy*

*Str. Cu?itul de Argint 5, RO-75212 Bucharest, Romania*

*E-mail: gbocsa@aira.astro.ro, teleanu@aira.astro.ro*

*Abstract*. The present paper joins the astrometric efforts to
determine precise positions for the asteroid 433 Eros. The observations
have been performed with a 380/6000 mm astrograph, in the intervals 19351938
and 19721975. Both methods: Turner (constants) and Schlesinger (dependencies)
were used for the computation of the normal coordinates of the asteroid.
*Key words*: astrometry 433 Eros.