The measurement of radial-velocity differences between the components of close visual binary systems

1971 ◽  
Vol 11 (1) ◽  
pp. 102-108 ◽  
Author(s):  
A. H. Batten ◽  
J. M. Fletcher
1965 ◽  
Vol 5 ◽  
pp. 102-108
Author(s):  
A. H. Batten ◽  
J. M. Fletcher

AbstractThe value obtained for the difference in radial velocity between components of a visual binary that is unresolved on the spectrograph slit appears to depend, sometimes, on whether the measurement is made visually with a microscope or by means of an oscilloscopic setting device. This apparent dependence has been confirmed by measurement of artificially produced double-lined spectrograms, and disappears for line pairs separated by more than 1.5 or 2 times the half-widths of their components. The dependence arises from blending of the two line profiles. There is some evidence that the results obtained from visual measures are affected by the scale of the image being measured. For this reason, oscilloscope measures are probably to be preferred; although their errors are sometimes larger, they seem to be more consistent. Errors arising from this sort of blending are not sufficient to explain measures of relative radial velocity of the components of some visual binaries, that differ widely from the predictions made from the visual orbits.


1971 ◽  
Vol 5 ◽  
pp. 102-108
Author(s):  
A. H. Batten ◽  
J. M. Fletcher

AbstractThe value obtained for the difference in radial velocity between components of a visual binary that is unresolved on the spectrograph slit appears to depend, sometimes, on whether the measurement is made visually with a microscope or by means of an oscilloscopic setting device. This apparent dependence has been confirmed by measurement of artificially produced doublelined spectrograms, and disappears for line pairs separated by more than 1.5 or 2 times the half-widths of their components. The dependence arises from blending of the two line profiles. There is some evidence that the results obtained from visual measures are affected by the scale of the image being measured. For this reason, oscilloscope measures are probably to be preferred; although their errors are sometimes larger, they seem to be more consistent. Errors arising from this sort of blending are not sufficient to explain measures of relative radial velocity of the components of some visual binaries, that differ widely from the predictions made from the visual orbits.


2009 ◽  
Vol 61 (1) ◽  
pp. 19-28 ◽  
Author(s):  
Eri Toyota ◽  
Yoichi Itoh ◽  
Shinichiro Ishiguma ◽  
Seitaro Urakawa ◽  
Daisuke Murata ◽  
...  

2011 ◽  
Vol 7 (S282) ◽  
pp. 33-40
Author(s):  
L. Eyer ◽  
P. Dubath ◽  
N. Mowlavi ◽  
P. North ◽  
A. Triaud ◽  
...  

AbstractTwo upcoming large scale surveys, the ESA Gaia and LSST projects, will bring a new era in astronomy. The number of binary systems that will be observed and detected by these projects is enormous, estimations range from millions for Gaia to several tens of millions for LSST. We review some tools that should be developed and also what can be gained from these missions on the subject of binaries and exoplanets from the astrometry, photometry, radial velocity and their alert systems.


2015 ◽  
Vol 11 (A29B) ◽  
pp. 642-647
Author(s):  
Hiromoto Shibahashi ◽  
Simon J. Murphy ◽  
Donald W. Kurtz

AbstractContinuous and precise space-based photometry has made it possible to measure the orbital frequency modulation of pulsating stars in binary systems with extremely high precision over long time spans. We present the phase modulation (PM) method for finding binaries among pulsating stars. We demonstrate how the orbital elements of a pulsating binary star can be obtained analytically from photometry alone, without spectroscopic radial velocity measurement. Frequency modulation (FM) caused by binary orbital motion also manifests itself in the Fourier transform, as a multiplet with equal spacing of the orbital frequency. The orbital parameters can also be extracted by analysing the amplitudes and phases of the peaks in these multiplets. We derive analytically the theoretical relations between the multiplet properties and the orbital parameters, and present a method for determining these parameters, including the eccentricity and the argument of periapsis. This, too, is achievable with the photometry alone, without spectroscopic radial velocity measurements. We apply these two methods to Kepler mission data and demonstrate that the results are in good agreement with each other. These methods are used to search for invisible binary companions, including planets and invisible massive objects such as neutron stars and stellar-mass black holes.


1980 ◽  
Vol 88 ◽  
pp. 271-286 ◽  
Author(s):  
Margherita Hack ◽  
Umberto Flora ◽  
Paolo Santin

The common peculiarities of these two systems are: a) the companion is a massive object (probably m2≥10) whose spectrum is not observable; b) both systems show evidence, though in different degrees, of mass-transfer and mass-loss; c) both present, in different degrees, hydrogen deficiency; d) ultraviolet observations have shown, in both cases, the presence of lines of highly ionized elements like N V, C IV, Si IV, probably formed in an extended envelope because they do not show orbital radial velocity shifts, and cannot be explained by the effective temperature of the star whose spectrum we observe. The latter property seems to be common to several close binaries, as shown by the ultraviolet observations with IUE by Plavec and Koch (1979); e) both systems present infrared excess, suggesting the presence of an extended envelope (Gehrz et al. 1974; Lee and Nariai, 1967; Humphreys and Ney, 1974; Treffers et al. 1976).


1999 ◽  
Vol 193 ◽  
pp. 26-37 ◽  
Author(s):  
Virpi S. Niemela ◽  
Roberto Gamen ◽  
Nidia I. Morrell ◽  
Sixto Giménez Benítez

Observations of WR stars in binary systems are discussed, emphasizing constraints on our knowledge of the binary frequency of WR stars, and of WR stars as a distinctive class of objects. Radial velocity orbits of newly discovered binaries, e.g., WR 29, a short period WN7+OB binary in our Galaxy, and SMC/AB 7, a massive WN+O7 binary in the Small Magellanic Cloud, are presented. New spectroscopic observations of binary systems with previously known orbits are also reported, showing in the case of WR 21 evidence of change of the orbital elements as derived from different spectral lines. An elliptic orbit for CV Ser is also illustrated.


1983 ◽  
Vol 62 ◽  
pp. 271-285 ◽  
Author(s):  
Alan H. Batten

AbstractThe special problems presented to the computer of orbits by radial-velocity observations of visual binaries are discussed under three heads: (i) problems caused by the small range of velocity variation, (ii) problems caused by the long periods, (iii) inconsistency between visual and spectroscopic observations. It is pointed out that radial-velocity observations, even when they are insufficient for independent determinations of orbital elements, impose constraints on possible values of those elements which may in fact be helpful to the computer of visual orbits. In particular, as is illustrated by reference to ADS 8189, even a few observations of the radial-velocity are sufficient to destroy the mutual independence of the elements e, and ω.


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