bluuebunny/crossref_metadata_2025_split huggingface dataset:
J-, H-, and K-band Spectra of Three SU UMa-Type Dwarf Novae
Authors: Ishioka Ryoko , Sekiguchi Kazuhiro , Maehara Hiroyuki 
Published: August 2007

AbstractWe present the results of J-, H-, and K-band spectroscopy on three SU UMa-type dwarf novae with orbital periods of 1.33 – 1.37 hr. We performed the SED fitting for the obtained spectra by assuming a power-law distribution for the accretion disk and using template spectra of late-type dwarfs for secondary star. ASAS 002511+1217.2 and EQ J183926+260409 are WZ Sge-type or WX Cet-type dwarf novae. We found strong water absorption features in their spectra, which are characteristic in late M- or L-type dwarfs. The SED fitting suggests that their secondary contributions to the overall SED are less than one third. We identified the secondary stars as M9 and L1 type dwarfs, which are rather less massive but still normal stars. The spectrum of SDSS J013701−091235 is dominated by the secondary component. Spectral features of this object are similar to those of an early M-type dwarf in spite of its short orbital period. The spectrum of SDSS 0137 strongly suggests that the evolutionary path of this object is different from that of ordinary CVs, and this object is a candidate of EI Psc-like systems.
Statistical Modeling and Analysis of Wide Binary Star Systems
Authors: Johnston K.B. , Oswalt T.D. , Valls-Gabaud D. 
Published: August 2007

AbstractPost-main-sequence (MS) mass loss causes orbital separation amplification in fragile (i.e. common proper motion) binary star systems. Components typically have separations around ∼1000 AU. Such wide pairs experience negligible tidal interactions and mass transfer between companions; thus they evolve as two separate but coeval stars. In this paper we compute the rate of mass loss during the components' lifetimes and attempt to model how it will statistically distort a frequency distribution of fragile binary separations. Understanding this process provides a robust test of current theories of stellar evolution and sets constraints on the dynamics of the Galactic disk.
The Orbit of T Tauri South
Authors: Köhler Rainer , Ratzka Thorsten 
Published: August 2007

AbstractWe report on previously unpublished diffraction-limited NIR observations of the young binary star T Tauri South. Orbital elements have been estimated by a least–squares fit to the relative positions. Although the parameters are not well constrained by the observations, we can derive a minimum system mass of about 3 M⊙.With the most recent astrometric measurements by Duchêneet al. (2006), hyperbolic (unbound) orbits can be excluded with high confidence. We conclude that T Tauri Sb isnotin the process of being ejected from the system.
Hunt for Binaries with Pulsating Components
Authors: Latković Olivera 
Published: August 2007

AbstractIn the frame of the collaboration of several Southern European observatories, we are examining a number of eclipsing binary systems in search for evidence of pulsating phenomena. We hope our candidate systems will be suitable for subsequent astroseismological studies. As a first step towards this end, we are analyzing spectroscopic observations of several such binary stars; these observations have been made at the National Astronomical Observatory Rozhen, Bulgaria, in the period from 2002 to 2005, and the reduction was done at the Astronomical Observatory of Belgrade, Serbia. The measurements of radial velocities and RV curve analysis are in preparation.
The Multiple System SZ Cam
Authors: Michalska Gabriela , Kubát Jiří , Korčáková Daniela , Kawka Adéla , Ceniga Michal , Kučerová Blanka , Votruba Viktor 
Published: August 2007

AbstractThe multiple stellar system SZ Cam is solved using the method of spectral disentrangling. Hα line profiles of three components are obtained and spectroscopic orbit elements are redetermined.
EUVE J0825-16.3 and EUVE J1501-43.6: Two dMe Double–Lined Spectroscopic Binaries
Authors: Montes D. , Crespo-Chacón I. , Gálvez M.C. , Fernández-Figueroa M.J. 
Published: August 2007

AbstractHigh-resolution echelle spectroscopic observations taken with the FEROS spectrograph at the ESO 2.2-m telescope confirm the binary nature of the dMe stars EUVE J0825−16.3 and EUVE J1501−43.6, previously reported by Christian & Mathioudakis (2002). In these binary systems, emission of similar intensity from both components is detected in the Na i D1 & D2, He i D3, Ca II H&K, Ca II IRT and Balmer lines. We have determined precise radial velocities by cross-correlation with radial velocity standard stars, which have allowed us to obtain for the first time the orbital solution of these systems. Both binaries consist of two nearly equal M0V components with an orbital period shorter than 3.5 days. We have analyzed the behaviour of the chromospheric activity indicators (variability and possible flares). In addition, we have determined its rotational velocity and kinematics.
On the Evolutionary History of Progenitors of EHBs and Related Binary Systems from their Observed Properties
Authors: Pustynski V.V. , Pustylnik I. 
Published: August 2007

AbstractIt has been shown quite recently (Morales-Rueda et al. 2003) that dB stars, extreme horizontal branch (EHB) objects in high probability all belong to binary systems. We study in detail the mass and angular momentum loss from the giant progenitors of sdB stars in an attempt to clarify why binarity must be a crucial factor in producing EHB objects. Assuming that the progenitors of EHB objects belong to binaries with initial separations of a roughly a hundred solar radii and fill in their critical Roche lobes while close to the tip of red giant branch, we have found that considerable shrinkage of the orbit can be achieved due to a combined effect of angular momentum loss from the red giant and appreciable accretion on its low mass companion on the hydrodynamical timescale of the donor, resulting in formation of helium WD with masses roughly equal to a half solar mass and thus evading the common envelope stage. A simple approximative analytical formula for mass loss rate from Roche lobe filling giant donor has been proposed depending on mass, luminosity and radius of donor.
Hydrodynamic Simulations of Irradiated Secondary Stars in Dwarf Novae
Authors: Viallet M. , Hameury J.H. 
Published: August 2007

AbstractWe investigate the possibility of a mass transfer enhancement during outburst in dwarf novae. We present here the first two-dimensional hydrodynamic simulations of the surface flows in the secondary, driven by the strong inhomogenous heating of the atmosphere during an outburst. We also discuss the possibility that the direct heating of the L1 point by the disc rim contributes to the mass transfer enhancement.
BVRI Light Curves and Period Analysis of the Beta Lyrae System XX Leonis
Authors: Zasche P. , Svoboda P. , Wolf M. 
Published: August 2007

AbstractThe contact eclipsing binary system XX Leonis (p = 0.97 days, Sp A9) has been analysed using the PHOEBE programme, based on the Wilson–Devinney code. The BVRI light curves were obtained during spring 2006 using the 20-cm telescope and ST-7 CCD detector. The effective temperature of the primary component determined from the photometric analysis is T = (7342 ± 14) K, the inclination of the orbit is i = (84.83 ± 0.29)° and the photometric mass ratio q = (0.40 ± 0.01). The third-body hypothesis was also suggested; based on a period analysis using 57 minimum times this gave a period for the third body of p3 = (59.66 ± 0.05) yr, an amplitude of A = (0.036 ± 0.028) day and zero eccentricity, which yields as a minimum mass M3,min = (0.91 ± 0.01) M⊙.
The Remarkable Eclipsing Binary TW Draconis
Authors: Zejda M. , Mikulášek Z. , Wolf M. , Svoboda P. 
Published: August 2007

AbstractWe analyzed a new photometry of this well-known Algol-like eclipsing binary together with old photoelectric measurements with the aim of better understanding of its orbital period changes and short-time light variations modulating the mean light curve. The analysis has been done by the new method based on the combination of the principal component analysis and robust regression. New spectroscopic observations and radial-velocity curve are also presented.
TWAN: A way of networking third-world astronomers
Authors: Narlikar Jayant V. 
Published: August 2007

AbstractThis talk describes a proposal to set up a series of international institutions in different parts of the world to serve as nodes in a network that links astronomers from the developing nations worldwide. This network, along with its nodes is visualized as an economic way of upgrading the facilities for teaching, research and development of astronomy in the Third World countries. By way of illustration, the modus-operandi of the Inter-University Centre for Astronomy and Astrophysics in Pune, India is described. A network of this kind is suggested as a cost-efficient way of sharing limited resources.
Astronomy in Colombia
Authors: Cepeda-Peña William E. 
Published: August 2007

AbstractAstronomy in Colombia has been done since the beginning of the nineteenth century, when in 1803 one of the oldest (or maybe the oldest) astronomical observatories of America was built. This is a very beautiful, historical and ancient building. A small dome with a small telescope is also inside the university campus. The observatory marks since then the development of astronomy in Colombia as a professional science. At the present time a Master's programme and a Specialization programme are successfully carried out with a good number of smart young students. The observatory has a staff of eleven professors, all with a master's degree in sciences; two of them have a PhD and in a couple of years five staff members will have a PhD in physics. With some international collaboration, they will introduce in a few years a doctoral astronomical program. There are several research lines mainly in the fields of astrometry, Galactic and extragalactic astronomy, cosmology, astro-statistics and astrobiology. Three research groups have got recognition from the governmental institution that supports the research in sciences COLCIENCIAS. Several papers have been published in national and international journals. Besides the professional line in astronomy, the observatory sponsors several non-professional Colombian astronomical groups that work enthusiastically in the field of astronomy.
Implementing an education and outreach programme for the Gemini Observatory in Chile
Authors: Ureta M. Antonieta García 
Published: August 2007

AbstractBeginning in 2001, the Gemini Observatory began the development of an innovative and aggressive education and outreach programme at its southern hemisphere site in northern Chile. A principal focus of this effort is centered on local education and outreach to communities surrounding the observatory and its base facility in La Serena, Chile. Programmes are now established with local schools using two portable StarLab planetaria, an internet-based teacher exchange called StarTeachers and multiple partnerships with local educational institutions. Other elements include a CD-ROM-based virtual tour that allows students, teachers and the public to experience the observatory's sites in Chile and Hawaii. This virtual environment allows interaction using a variety of immersive scenarios such as a simulated observation using real data from Gemini. Pilot projects like “Live from Gemini” are currently being developed which use internet video-conferencing technologies to bring the observatory's facilities into classrooms at universities and remote institutions. Lessons learned from the implementation of these and other programmes will be introduced and the challenges of developing educational programming in a developing country will be shared.
Astronomy in the cultural heritage of African societies
Authors: Baki Paul 
Published: August 2007

AbstractThe African perspectives of astronomy are explored from the point of view of using indigenous knowledge of the night sky for purposes of addressing local challenges such as food insecurity and periodic natural weather phenomena such as droughts and floods. The local ethnic groups use stellar positions, and plant and animal behaviour changes for purposes of forecasting the weather and climate for the coming seasons. These traditional indicators give rise to an interdisciplinary discourse that could benefit the community in environmental protection measures and boost the tourism industry in some countries in Africa.
Astronomy in Asia
Authors: Soonthornthum Boonrucksar 
Published: August 2007

AbstractAstronomy in Asia has continuously developed. Local wisdom in many Asian countries reflects their interest in astronomy since the historical period. However, the astronomical development in each country is different which depends on their cultures, politics and economics. Astronomy in some Asian developing countries such as China and India are well-developed while some other countries especially in south-east Asia, with some supports such as telescopes, training, experts etc. from some developed countries, are trying to promote relevant research in astronomy as well as use astronomy as a tool to promote scientific awareness and understanding for the public. Recently, a new national research institute in astronomy, called the National Astronomical Research Institute of Thailand (NARIT), with a 2.4-metre reflecting telescope has been established in Thailand. One of the major objectives of this research-emphasis institute would aim at a collaborative network among South-East Asian countries so as to be able to contribute new knowledge and research to the astronomical community.
Mutual collaboration between Institute of Technology Bandung, Indonesia and Gunma Astronomical Observatory, Japan
Authors: Hashimoto Osamu , Malasan Hakim L. , Taguchi H. , Kinugasa K. , Dermawan B. , Indradjaja B. , Kozai Y. 
Published: August 2007

AbstractInstitute of Technology Bandung (ITB), Indonesia and Gunma Astronomical Observatory (GAO), Japan have been proceeding with several programmes of mutual collaboration in the fields of astronomical research and education since 2002. ITB with Bosscha observatory has a great interest in education of astronomy for public people as well as in the university education and research of their own, and GAO is a public observatory operated by Gunma prefecture local government equipped with a 150-cm reflector and some smaller telescopes, which are capable of scientific research of high grade. We will report some of our cooperative activities including the remote accessing of the telescopes of each observatory by each other, which can provide opportunities for astronomical experiences of the opposite hemisphere for various people of each country. Some scientific collaboration works such as common instruments and data analysis systems developed on both sites are also reported.
Astronomy in Iran
Authors: Sobouti Yousef 
Published: August 2007

AbstractThis paper summarizes the present situation concerning astronomy in Iran. Shiraz University introduced astronomy in the mid-1960s and established the Biruni Observatory. Astronomy is also carried out at Tabriz University and in Meshed, Zanjan, Tehran, Babol and other places. The Astronomical Society of Iran is flourishing, and is about 30 years old. Site-testing is underway for a National Observatory of Iran, which will be equipped with a 2-m class optical telescope. Iran publishes Nojum, the only astronomical monthly magazine of the Middle East, which is presently in its fifteenth year.
Relativistic astrophysics and cosmology in Uzbekistan
Authors: Ahmedov Bobomurat J. , Zalaletdinov Roustam M. , Turakulov Zafar Ya. , Nuritdinov Salakhutdin N. , Mirtadjieva Karomat T. 
Published: August 2007

AbstractThe theoretical results obtained in Uzbekistan in the field of relativistic astrophysics and cosmology are presented. In particular electrostatic plasma modes along the open field lines of a rotating neutron star and Goldreich-Julian charge density in general relativity are analyzed for the rotating and oscillating magnetized neutron stars. The impact that stellar oscillations of different type (radial, toroidal and spheroidal ones) have on electric and magnetic fields external to a relativistic magnetized star has been investigated. A study of the dynamical evolution and the number of stellar encounters in globular clusters with a central black hole is presented. Perturbation features and instabilities of the large-scale oscillations on the background of the non-linearly pulsating isotropic and isotropic Ω-models are studied. The non-stationary dispersion equation of the sectorial perturbations for the general case and the results of certain oscillation mode analysis are given. The model composed as the linear superposition of two other models was constructed and the stability of this model is studied. In a cosmological setting the theory of macroscopic gravity as a large-distance scale generalization of general relativity has been developed. Exact cosmological solutions to the equations of macroscopic gravity for a flat spatially homogeneous, isotropic space-time are found. The gravitational correlation terms in the averaged Einstein equations have the form of spatial curvature, dark matter and dark energy (cosmological constant) with particular equations of state for each correlation regime. Interpretation of these cosmological models to explain the observed large-scale structure of the accelerating Universe with a significant amount of the nonluminous (dark) matter is discussed.
IHY: Meteor astronomy and the New Independent States (NIS) of the Former Soviet Union
Authors: Kolomiyets Svetlana V. , Sidorov Vladimir V. 
Published: August 2007

AbstractThe purpose: to emphasize, that there are some specific features of the development of science in the New Independent States (NIS) of the Former Soviet Union. These features demand enhanced attention of the organizers of the IHY. It is necessary to create effective mechanisms for the stimulation of the connection to world science of the dormant part of fundamental scientific knowledge of these countries, which has been saved up for fifty of years. Probably, the IHY is the last opportunity of rescuing the dormant part of this knowledge from full oblivion.The method adopted is to discuss and analyse the general tendencies in science in the NIS by reference to individual cases, in particular for meteor astronomy.Results: The features and history of the development of meteor astronomy during the existence of the Soviet Union and the subsequent period give a key to understanding of the problem. Meteor astronomy can be assumed to be a young science. It is an example of a cross-disciplinary science. It is an example of a science having a sharp rise, due to the project of the IGY and to subsequent geophysical projects. Meteor astronomy is a science directly connected with the launching of the first space satellite of the Earth and the evaluation of problems of meteoroid danger to space missions.Commission 22 (Division III) of the IAU coordinated the development of meteor astronomy during the IGY. The known Soviet researcher of meteors V. Fedynskiy headed this Commission during four years since 1958. In the USSR numerous meteor centres were created and activated. The general management was concentrated in Moscow. Despite the close interaction under global projects of the Soviet Union with other countries, there still existed a language barrier. The language barrier, together with other reasons, has led to the creation in the USSR of a powerful meteor science, but only in the Russian language.After the disintegration of the Soviet Union, the meteor centres have remained, but without ordinary central management. The scientific results have remained but as an isolated, inaccessible science published in English.Conclusion: Reunification of the scientific achievements of the last few years in the NIS with international science should become the task of the IHY. Revival of the activity of the some of the centres will be useful.
Astronomy and astrophysics in Bosnia and Herzegovina
Authors: Andic Aleksandra 
Published: August 2007

AbstractIn Bosnia and Herzegovina astronomy teaching is almost nonexistent. There are only several courses within universities and they are usually given by physicists who themselves have had only elementary courses in astrophysics. When educational outreach is in question, the situation is even more grim. On the other hand, there is a huge interest for astrophysics in the student population. There are several solutions and possibilities which I will present, together with a discussion of the main obstacles which need to be overcome.
How to look for planetary transits using small telescopes and commercial CCDs in developing countries
Authors: Martioli Eder , Jablonski F. 
Published: August 2007

AbstractThe main goal of this work is to have a better understanding of the problems and characteristics of photometric surveys with small-sized affordable equipment, like the one available at the Astrophysics Division/INPE, in São José dos Campos, Brazil. The use of low-cost instruments is appealing in the context of the detection of Extrasolar Planets (ESP), in the sense that many observers are available for survey and follow-up programmes. It could also make possible the inclusion of many developing countries in the search for planetary transits. We describe the data collection and analysis procedure for differential photometry of the transit of HD 209458 b, using a small telescope and a commercial CCD camera. According to the HST observations of Brown et al. (2001), the transit produces a box-shaped light curve with 2% depth and 184-min duration. The orbital period is ∼ 3.5 days. The equipment consists of a f/10, 11” Schmidt-Cassegrain Celestron telescope equipped with a SBIG ST7E CCD camera. Since the seeing at the campus is quite poor, we used a focal reducer to produce an effective focal ratio of about f/5, still keeping a good sampling of the PSF but with a larger field of view. The larger field of view allows the simultaneous observation of a relatively bright nearby star, suitable for differential photometry. We discuss the IRAF reduction procedures for the large number of images collected and present the results obtained in the transit of September 8, 2004
Basic astronomy as part of a general higher education in the developing world
Authors: Baruch John , Hedges Dan , Machell James , Norris K. , Tallon Chris 
Published: August 2007

AbstractThis paper describes a new initiative in support of the aim of Commission 46 of the IAU to develop and improve astronomy education at all levels throughout the world. This paper discusses the ideal specification of a facility to support basic astronomy within education programmes which are delivered to students who have access to the Internet. The available robotic telescopes are discussed against this specification and it is argued that the Bradford Robotic Telescope, uniquely, can support many thousands of users in the area of basic astronomy education, and the resource is free.Access to the Internet is growing in the developing world and this is true in education programmes. This paper discusses the serious problems of delivering to large numbers of students a web based astronomy education programme supported by a robotic telescope as part of a general education. It examines the problems of this form of teaching for teachers who have little experience of working with IT and little knowledge of basic astronomy and proposes how such teachers can be supported.The current system (http://www.telescope.org/) delivers astronomy education in the language, culture and traditions of England. The paper discusses the need to extend this to other languages, cultures and traditions, although for trainee teachers and undergraduates, it is argued that the current system provides a unique and valuable resource.