THE LOCAL STELLAR VELOCITY DISTRIBUTION OF THE GALAXY
MARIAN
DORU
ŞURAN 1, ADINA IONESCU 2, NEDELIA ANTONIA POPESCU
1
1 Astronomical
Institute of the
Str.
Cuţitul de
Argint 5, RO-752121 Bucharest, Romania
E-mail:
suran@aira.astro.ro, delia@aira.astro.ro
2 Faculty
of Mathematics,
Str.
Academiei 14,
Abstract. This paper deals
with systematic [r, B–V, MV]
calculations of the
kinematical parameters in the solar neighbourhood
using a combination of the
Hipparcos and Barbier-Brossat catalogues. A series of new kinematical
and dynamical
features are
pointed, together with severe limitations and biasing of the two
catalogues. The implications for the local and global dynamics of
the Galaxy
are also discussed.
Key words: stars – solar neighbourhood kinematics – Galaxy dynamics.
A VARIABLE MODEL OF THE FINE-STRUCTURE CONSTANT
IOANNIS IRAKLIS HARANAS
Department of Physics and Astronomy
E-mail:
ioannis@yorku.ca
Abstract. Recent evidence
suggests that the fine-structure constant α = e2/(ħc), a measure of the strength of the electromagnetic
interaction
between photons and electrons, is slowly increasing over cosmological
timescales. High-resolution measurements of
quasar spectra suggest that there
has been a variation Da/a = –0.72 ± 0.18´10-5 over the past 6–10 Gyr
(Davies et al. 2002).
To model this, we propose variability in the speed of
light that produces a cosmological time variation |
|
= 10–15 and 10–16 yr–1
at z = 3 which also agrees with the
observational spectral data.
Key words: cosmology – fundamental constants – quantum electrodynamics.
CONTRIBUTION À
L’ÉTUDE DES BINAIRES DES TYPES
F, G, K,
M. IX. HD 191588,
NOUVELLE BINAIRE
SPECTROSCOPIQUE À
RAIES
SIMPLES DE TYPE
RS CVN, SYSTÈME
TRIPLE
ROGER
F. GRIFFIN 1, NICOLE
GINESTET 2,
JEAN-MICHEL CARQUILLAT 2
1
The Observatories,
E-mail:
rfg@ast.cam.ac.uk
2 Observatoire Midi-Pyrénées, UMR 5572,
14,
avenue Edouard
Belin, F-31400 Toulouse, France
E-mail:
carquillat@ast.obs-mip.fr
Résumé. Une erreur d’identification est à l’origine de la
découverte d’un
intéressant système, HD 191588, une nouvelle binaire
spectroscopique de type RS
CVn. Une étude de la vitesse radiale de l’étoile
primaire, seule composante visible,
entreprise à
l’Observatoire de Haute-Provence au moyen de l’instrument CORAVEL
et poursuivie à l’Observatoire de Cambridge avec un
appareil similaire, révèle
l’existence d’une orbite à courte période (60 jours), et
une autre à longue
période (4 ans et demi); il
s’agit d’un système triple. Les éléments orbitaux
sont: (1) pour l’orbite à longue période P
= 1667 ± 17 jours, T = 50901 ± 67 JJM,
G = +2,09 ± 0,07 km s-1, K =
2,51 ± 0,13 km s-1, e =
0,18 ± 0,04, w = 228° ± 14°, a1
sin i = 56,7 ± 3,0 Gm, f(m) =
0,0026 ± 0,0004 MΘ,
et (2) pour l’orbite à courte période P
= 60,0269 ± 0,0016 jours,
T = 50482,6 ± 3,3 JJM, g var., K
= 24,03 ± 0,09 km s-1,
e =
0,012 ± 0,004, w = 233° ± 19°, a1
sin i = 19,83 ± 0,07 Gm, f(m) =
0,0865 ± 0,0009 MΘ. À partir d’observations dans le
proche infrarouge,
on trouve pour la composante primaire un type spectral K2,5 III; un
spectre
obtenu dans le bleu – proche UV
révèle de fortes raies H et K de Ca II en
émission. La secondaire pourrait être de type solaire (F
ou G V); la masse
minimum du
troisième corps est celle d’une naine de type M. La primaire
tourne
probablement en synchronisme avec le mouvement orbital au sein
du système à
courte période. Un modèle, basé sur cette
hypothèse, est proposé. Son
appartenance aux binaires de type RS CVn est discutée.
Mots clés:
binaires spectroscopiques - systèmes triples - étoile HD 191588.
PHOTOMETRIC OBSERVATIONS OF THE CONTACT BINARY V2388 OPH IN 2001
ALEXANDRU DUMITRESCU1, LUBOMIR ILIEV2
1Astronomical
Institute of the
Str.
Cuţitul de
Argint 5, RO-752121, Bucharest, Romania
E-mail:
alex@aira.astro.ro
2Astronomical
Institute of the
72
Tsarigradsko Shossee Blvd., BG-1784 Sofia, Bulgaria
E-mail:
liliev@astro.bas.bg
Abstract. The paper
presents the ground-based photoelectric observations of
the relative newly discovered eclipsing binary
V2388 Ophiuchi. The observations
were carried out at Rozhen Observatory (
The light curves in UBV magnitudes are presented.
Key words: astrophysics – photoelectric photometry – eclipsing binaries – V2388 Oph.
SINGULARITIES OF THE DIFFERENTIAL ROTATION VELOCITY OF FILAMENTS WITHIN THE SOLAR CYCLE
CRISTIANA DUMITRACHE
Astronomical
Institute of the
Str.
Cuţitul de
Argint 5, RO-752121 Bucharest, Romania
E-mail:
crisd@aira.astro.ro
Abstract. The active
longitude intervals of filaments along the interval
1957–1989 are determined. The filaments with pivot-points are
computed as
singularities of the differential rotation velocity. A comparative
study of the
rigid rotation of the filaments with pivot-point
and the active longitude
intervals of all filaments is done. If the pivot-point filaments reveal
singularities of the differential rotation velocity,
the active longitude still
rests an enigmatic behavior of the solar activity.
Key words: Sun – differential rotation – prominences – pivot-point – active longitudes.
BINARY COLLISIONS IN POPOVICI-MANEV’S PHOTOGRAVITATIONAL MODEL
VASILE MIOC, MAGDA STAVINSCHI
Astronomical
Institute of the
Str.
Cuţitul de
Argint 5, RO-752121 Bucharest, Romania
E-mail:
vmioc@aira.astro.ro, magda@aira.astro.ro
Abstract. The dynamics of
bodies under the combined action of gravitation
and radiation has large and deep implications in astronomy.
In the 1920s, based
on physical arguments, the Romanian astronomer Constantin Popovici
proposed a
modified radiative force, while
the Bulgarian physicist proposed a classical
post-Newtonian force. This paper deals with the collisions of the
two-body
problem associated
to a photogravitational field resulted from the combination
of the two models: the Popovici-Manev’s field. Resorting to
McGehee-type
transformations of the second kind, we obtain regular equations of
motion and
define the collision manifold. The flow on this boundary manifold
is fully
described. This allows to point out some important qualitative features
of the
collisional motion: existence of the black-hole effect,
gradientlikeness of the
flow and regularizability of solutions under certain conditions,
bifurcations,
etc.
Key words: celestial mechanics – photogravitational models – collisions – McGehee-type transformations.
SYMMETRIES OF FOCK’S TWO-BODY PROBLEM (II)
VASILE MIOC 1, MIRCEA RUSU 2, MAGDA STAVINSCHI 1
1 Astronomical
Institute of the
Str.
Cuţitul de
Argint 5, RO-752121 Bucharest, Romania
E-mail:
vmioc@aira.astro.ro, magda@aira.astro.ro
2 University
of
Str.
Atomiştilor 1, CP MG-11, RO-76900
E-mail: mrusu@dnt.ro
Abstract. A general view on
the symmetries that characterize the two-body
problem associated to Fock’s field is provided. In both
Cartesian or standard
polar coordinates, as well as in collision-blow-up and infinity-blow-up
McGehee-type coordinates, these symmetries
form isomorphic eight-element
Abelian groups endowed with an idempotent structure. For Levi-Civita’s
regularizing coordinates, we find a
sixteen-element group of symmetries with
the same characteristics.
Key words: celestial mechanics – relativistic fields – symmetries.
Reduction of
compiled catalogue in the selected
extragalactic radio source
fields.
PRELIMINARY ESTIMATION
YuRI Babenko1, ALEXANDER Daniltsev1, ALEXANDER Vertypolokh1, NADEZHDA MAIGUROVA2, GENNADY Pinigin2, YuRI Protsyuk2, ALEXANDER Shulga2, ANNA DementYeva3, VLADIMIR Ryl’kov3, GHEORGHE BocŞa4, PETRE Popescu4
1 Astronomical
Observatory of
Str.
Observatorna 3, 04053 Kyiv-53,
E-mail:
verto@observ.univ.kiev.ua
2 Nikolaev Astronomical Observatory
Str.
Observatorna 1, 54030 Mykolajiv-30,
E-mail: yuri@mao.nikolaev.ua
3 Main
Astronomical Observatory of the
Pulkovskoje
Shosse 65/1, 196140
St-Petersburg-140,
E-mail: vryl@gao.spb.ru
4 Astronomical
Institute of the
Str.
Cuţitul de
Argint 5, 752121 Bucharest, Romania
E-mail:
gbocsa@aira.astro.ro
Abstract. The work is
devoted to the problem of deriving the compiled
catalogue of the positions of reference stars 12–15m in the
ICRF ERS
neighbourhood for –20º < δ < 90º. Astronomical
Observatory of Kyiv University, Nikolaev
Astronomical Observatory, Main Astronomical
Observatory of the
The catalogue is based on both original
astrometric materials from these observatories and other known
catalogues of
stars in the ICRF ERS
neighbourhood. Its first version is planned to appear in
2003.
Key words: reference stars – compiled catalogue – extragalactic radio source fields.
ARCHIVE OF PHOTOMETRIC PLATES OBTAINED AT CLUJ ASTRONOMICAL OBSERVATORY
CRISTINA BLAGA, GHEORGHE-DORIN CHIŞ, LIVIU MIRCEA
Astronomical
Institute of the
Astronomical
Observatory Cluj-Napoca
Str.
Cireşilor
19, RO-3400 Cluj-Napoca, Romania
E-mail:
cpblaga@math.ubbcluj.ro, tucu165@email.ro, mirliviu@email.ro
Abstract. The archive of
photometric plates obtained at the Astronomical
Observatory of Cluj in the period 1952–1974 is presented.
The plate inventory
is made within the framework of the Wide-Field Plate Database project.
The
plates were taken in the regions around
110 variable stars (eclipsing variables
and RR Lyrae-type stars), as well as in some comparison stars regions.
Key words: variable stars – photographic plates archive.
FOUNDATIONS FOR A NEW BASIC COSMOS-MODEL. EINSTEIN – ONLY PART OF A WHOLE
GERD
HELMECKE 1, ULRICH
HERKENRATH 2
1 Königstr. 4,
D-53773 Hennef, Germany
E-mail:
dok-helmecke@t-online.de
2
Gerhard-Mercator-Universität Duisburg,
Fakultät 4/Institut für Mathematik
Lotharstr.
65,
D-47057 Duisburg, Germany
E-mail:
herkenrath@math.uni-duisburg.de
Abstract. Whenever the
explanation of a system is one's aim, particularly
that of the universe or the 'cosmos' as it was called by the
Greeks, the essential
components and comprehensive laws on which the system is based must be
known. A
model for the universe
should be a maximal one which offers room for all models
which are built for subdomains of natural reality. We call such a model
“Basic
Cosmos-Model” (abbreviated to BCM). In the following we present
foundations for
a BCM which are new in so far as they
are designed with regard to a broader and
more comprehensive pretension than the 4-dimensional spacetime
continuum of
relativistic
physics built by Einstein. We call these principles for
structuring space, time, masses and their interactions Cosmic
Laws. We think that
these laws present guidelines for the
design, respectively the construction of models of natural reality. We
consider
this approach an
appropriate feasibility to represent natural reality in a
comprehensive way and to exclude misleadings and inexplicable
“singularities”.
Key words: Cosmos models – critical stability – evolutionary causality – multidimensional universe.