Science Abstracts


Book Description




Science with the VLT Interferometer


Book Description

It has always been ESO's aim to operate the VLT in an interferometric mode (VLTI) which allows the coherent combination of stellar light beams col lected by the four 8-m telescopes and by several smaller auxiliary telescopes. In December 1993, in response to financial difficulties, the ESO Council de cided to postpone implement at ion of the VLTI, Coude trains and associated adaptive optics for all the UTs but included provisions for continuing tech nological and development programmes devoted to the aim of reintroducing these capabilities at the earliest possible date. The desirability of carrying out the full VLTI programme as originally envisaged at the earliest possible moment has not, however, diminished, es pecially in view of VLTI's exceptional capabilities and resulting potential for new and exciting discoveries. In recent years, interferometric projects have begun to playa central role in ground-based high-resolution astronomy, and numerous instruments have been completed or are in the process of construc tion. Several large-aperture interferometers will probably co me on-line near the turn of the century. The impending presence of these new instruments represents an important incentive both for clarifying the scientific cases for various VLTI implementation plans and for ensuring VLTI's competitiveness in the international context over the next 1O~20 years.




Encyclopedia of Astronomy & Astrophysics


Book Description

In a unique collaboration, Nature Publishing Group and Institute of Physics Publishing have published the most extensive and comprehensive reference work in astronomy and astrophysics. This unique resource covers the entire field of astronomy and astrophysics and this online version includes the full text of over 2,750 articles, plus sophisticated search and retrieval functionality and links to the primary literature. The Encyclopaedia's authority is assured by editorial and advisory boards drawn from the world's foremost astronomers and astrophysicists. This first class resource is an essential source of information for undergraduates, graduate students, researchers and seasoned professionals, as well as for committed amateurs, librarians and lay people wishing to consult the definitive astronomy and astrophysics reference work.




Fundamental Stellar Properties: The Interaction Between Observation and Theory


Book Description

This Symposium began with a proposal for a meeting to honour Emer itus Professor Robert Hanbury Brown on the occasion of his 80th birthday. He requested that any such meeting should be on a topic that would be of benefit to the Sydney University Stellar Interferometer (SUSI) program. With SUSI and several other high angular resolution instruments either in operation or coming on line within the next decade, and with advances in astrometry, spectroscopy and in theoretical models of stellar atmospheres and interiors, it appeared to be both appropriate and timely to hold a symposium on "Fundamental Stellar Properties: the Interaction between Observation and Theory. " The emphasis of the meeting was on the critical assessment of the qual ity, accuracy, and prospects for improvement of the observational data and theoretical models, on the outstanding problems in stellar astrophysics, and on the feasibility of achieving the observational and theoretical advances required for their solution. Invited papers comprised the major part of the oral program and the speakers responded to the challenge issued by the Scientific Organising Committee to critically review the current status and prospects for their area of expertise. The Symposium was opened by the Chancellor of the University of Sydney, Emeritus Professor Dame Leonie Kramer, who welcomed the 126 participants from 22 countries on behalf of the University. The oral program included . 52 invited reviews and papers and 10 contributed papers.




Visual Double Stars: Formation, Dynamics and Evolutionary Tracks


Book Description

This workshop is devoted to Double stars. The general topics of the meeting were: for mation, dynamics and evolutionary tracks. In accordance with the pure tradition of the Saint James way, "pilgrims" from all over the world come to meet together in Santiago. Although with a common interest (double stars), this meeting was a multidisciplinary one, since scientists with different backgrounds participated in it. As a matter of fact, we think that this is the first workshop jointly supported by IAU Commissions 7 (Celestial mechanics) and 26 (Double and multiple stars). It is our belief that this meeting will be the origin of a more close relations and common research. This meeting was held under the invitation of the University of Santiago de Compostela to commemorate its fifth centenary, and organized by the Astronomical Observatory named after its founder, Ramon M. Aller, who made significant contributions in the study of visual double stars, and was one of the pioneers who put the seeds of the present blossoming of Astronomy in Spain. The Scientific Organizing Committee was formed by Drs. C. Allen, P. Couteau, J. A. Docobo, R. Dvorak, A. Elipe, S. Ferraz-Mello (co-chairman), H.A.McAlister, M. Valtonen, C.Worley (chairman) and H. Zinnecker. The Local Organizing Committee was formed by Drs. J. A. Docobo (chairman), A.




Planets in Binary Star Systems


Book Description

In 1988, in an article on the analysis of the measurements of the variations in the radial velocities of a number of stars, Campbell, Walker, and Yang reported an - teresting phenomenon;the radial velocity variations of Cephei seemed to suggest the existence of a Jupiter-like planet around this star. This was a very exciting and, at the same time, very surprising discovery. It was exciting because if true, it would have marked the detection of the ?rst planet outside of our solar system. It was surprising because the planet-hosting star is the primary of a binary system with a separation less than 19 AU, a distance comparable to the planetary distances in our solar system. The moderatelyclose orbit of the stellar companionof Cephei raised questions about the reality of its planet. The skepticism over the interpretation of the results (which was primarily based on the idea that binary star systems with small sepa- tions would not be favorable places for planet formation) became so strong that in a subsequent paper in 1992, Walker and his colleagues suggested that the planet in the Cephei binary might not be real, and the variations in the radial velocity of this star might have been due to its chromospheric activities.







An Introduction to Optical Stellar Interferometry


Book Description

During the last two decades, optical stellar interferometry has become an important tool in astronomical investigations requiring spatial resolution well beyond that of traditional telescopes. This book, first published in 2006, was the first to be written on the subject. The authors provide an extended introduction discussing basic physical and atmospheric optics, which establishes the framework necessary to present the ideas and practice of interferometry as applied to the astronomical scene. They follow with an overview of historical, operational and planned interferometric observatories, and a selection of important astrophysical discoveries made with them. Finally, they present some as-yet untested ideas for instruments both on the ground and in space which may allow us to image details of planetary systems beyond our own.