scholarly journals Observations of Binary Protostellar Systems

2004 ◽  
Vol 221 ◽  
pp. 213-222
Author(s):  
Ralf Launhardt

A major gap in our understanding of star formation concerns the origins of binary stars although there is growing evidence that most stars form in binary and multiple systems. While some theoretical predictions of fragmentation models are indirectly supported by statistical studies of evolved binary stars at shorter wavelengths, direct observations of the formation phase became only possible with the advance of large millimeter interferometers. Molecular line spectroscopy and dust continuum observations at high angular resolution can address some of the key questions in binary star formation theories. Observing methods and results of recent studies of binary protostellar systems are reviewed in this paper.

2001 ◽  
Vol 200 ◽  
pp. 547-554 ◽  
Author(s):  
Stéphane Guilloteau

ALMA, the Atacama Large Millimeter / Sub-millimeter Array will be the first instrument allowing very high angular resolution (down to 0.01″) with sufficient sensitivity to image thermal emission from dust and molecules in proto-planetary disks at wavelengths where these disks are optically thin. Its unsurpassed characteristics will make it a premier instrument to study the formation of binary and multiple systems. I present here the projected characteristics of ALMA, in particular the expected sensitivities and frequency coverage, and illustrates some possible applications relevant to the study of binary star formation.


1991 ◽  
Vol 147 ◽  
pp. 526-528
Author(s):  
Hans Zinnecker

I propose and briefly elaborate on a major new mechanism for the formation of wide, low-mass binary stars: the fragmentation of a collapsing, initially elongated dense molecular core rotating end over end. This initial structure will develop into two independent gravitationally bound stellar condensations orbiting each other in a rather eccentric orbit.


1991 ◽  
Vol 147 ◽  
pp. 526-528
Author(s):  
Hans Zinnecker

I propose and briefly elaborate on a major new mechanism for the formation of wide, low-mass binary stars: the fragmentation of a collapsing, initially elongated dense molecular core rotating end over end. This initial structure will develop into two independent gravitationally bound stellar condensations orbiting each other in a rather eccentric orbit.


1985 ◽  
Vol 111 ◽  
pp. 97-119
Author(s):  
Harold A. McAlister

With the advent of speckle interferometry, high angular resolution has begun to play a routine role in the study of binary stars. Speckle and other interferometric techniques not only bring enhanced resolution to this classic and fundamental field but provide an equally important gain in observational accuracy. These methods also offer the potential for performing accurate differential photometry for binary stars of very small angular separation. This paper reviews the achievements of modern interferometric techniques in measuring stellar masses and luminosities and discusses the special calibration problems encountered in binary star interferometry. The future possibilities for very high angular resolution studies of close binaries are also described.


Author(s):  
Oleg Malkov ◽  
Aleksey Karchevsky ◽  
Pavel Kaygorodov ◽  
Dana Kovaleva ◽  
Nikolay Skvortsov

Binary star DataBase (BDB) is the database of binary/multiple systems of various observational types. BDB contains data on physical and positional parameters of 260,000 components of 120,000 stellar systems of multiplicity 2 to more than 20, taken from a large variety of published catalogues and databases. We describe the new features in organization of the database, integration of new catalogues and implementation of new possibilities available to users. The development of the BDB index-catalogue, Identification List of Binaries, is discussed. This star catalogue provides cross-referencing between most popular catalogues of binary stars. We describe ideas and methods for reliable cross-identification of different entities (systems, pairs, components) in binary and multiple stellar systems.


2001 ◽  
Vol 200 ◽  
pp. 210-218 ◽  
Author(s):  
Andrea M. Ghez

We review current observations of binary star populations with particular attention to what insight these populations can give us into the problem of how binary stars form. Significant progress has been made in the past few years, revealing variations as a function of site, primary star mass, and binary star separations. The variations in the binary star population with type of star formation site in comparison with the field, suggests that ∼30% of the field binaries formed in loose T associations and ∼70% formed in the dense progenitors of open clusters. Variations with mass and separation on the whole are well matched by the predictions of fragmentation followed by competitive accretion. However, there remains much work to be done on both the observational and theoretical end before a complete picture of binary star formation can be developed.


2011 ◽  
Vol 7 (S282) ◽  
pp. 409-416
Author(s):  
C. J. Clarke

AbstractBinary stars provide an excellent calibration of the success or otherwise of star formation simulations, since the reproduction of their statistical properties can be challenging. Here, I summarise the direction that the field has taken in recent years, with an emphasis on binary formation in the cluster context, and discuss which observational diagnostics are most ripe for meaningful theoretical comparison. I focus on two issues: the prediction of binary mass ratio distributions and the formation of the widest binaries in dissolving clusters, showing how in the latter case the incidence of ultra-wide pairs constrains the typical membership number of natal clusters to be of order a hundred. I end by drawing attention to recent works that include magnetic fields and which will set the direction of future research in this area.


2011 ◽  
Vol 7 (S282) ◽  
pp. 271-278 ◽  
Author(s):  
A. Prša ◽  
E. F. Guinan ◽  
E. J. Devinney ◽  
P. Degroote ◽  
S. Bloemen ◽  
...  

AbstractWith the launch of NASA's Kepler mission, stellar astrophysics in general, and the eclipsing binary star field in particular, has witnessed a surge in data quality, interpretation possibilities, and the ability to confront theoretical predictions with observations. The unprecedented data accuracy and an essentially uninterrupted observing mode of over 2000 eclipsing binaries is revolutionizing the field. Amidst all this excitement, we came to realize that our best models to describe the physical and geometric properties of binaries are not good enough. Systematic errors are evident in a large range of binary light curves, and the residuals are anything but Gaussian. This is crucial because it limits us in the precision of the attained parameters. Since eclipsing binary stars are prime targets for determining the fundamental properties of stars, including their ages and distances, the penalty for this loss of accuracy affects other areas of astrophysics as well. Here, we propose to substantially revamp our current models by applying the lessons learned while reducing, modeling, and analyzing Kepler data.


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