Determination Of Mass Ratio Research Articles

An attempt to understand RT Sculptoris

The metal-deficient star RT Sculptoris is a rare binary showing a secularlydecreasing period, probably due to mass transfer from the more to the less massive component. The somewhat difficult photometric solution indicates a semi-detached configuration with one star only very slightly smaller than its limiting lobe. Probably it is the more massive and lower temperature star which fills its lobe. The photometric solution for the mass ratio (q) is especially troublesome, as there are at least two (nearly equally deep) minima in parameter space-one atq=1.10 and another atq=1.67. The few existing radial velocity observations are inadequate for a determination of the mass ratio, but do point to absolute masses which are about half of those expected. We look into the question of whether this result can be understood in terms of low metallicity, and conclude that a significant part of the discrepancy can be so explained. The remainder could be due to accretion luminosity and to evolution. Some comments are made in regard to whether RT Sculptoris is likely to evolve into a contact system.

An Improved Derived Value for the Neutron Magnetic Moment in Nuclear Magnetons

The recent proton to electron mass ratio determination of Van Dyck and Schwinberg can be combined with earlier measurements of Greene et al to obtain a more accurate value of the neutron magnetic moment expressed in nuclear magnetons. We find μn/μN = 1.91304308 (54) (0.28 ppm).

A direct determination of the proton electron mass ratio

The cyclotron frequencies of free protons and electrons in a magnetic field of 5.81 Tesla with superimposed electrostatic quadrupole field have been measured. The increase of energy connected with a transition at cyclotron frequency is detected by the measurement of the time of flight through an inhomogeneous magnetic field. From the ratio of the measured cyclotron frequencies of both particles the proton electron mass ratio is deduced. The resultm p /m e =1,836.1527(11) agrees within the limits of error (0.6 ppm) with the value of the indirect determination.

Masses and Evolution of Cataclysmic Binaries

The determination of masses and mass ratios of cataclysmic binaries is discussed. It is suggested that these systems started as wide binaries, which have lost substantial amounts of mass and still more substantial amounts of angular momentum.

Electrodynamic determination of fine-structure constant and electron-muon mass ratio from Weinberg’s renormalization group equations

Electrodynamic determination of fine-structure constant and electron-muon mass ratio from Weinberg’s renormalization group equations

Mass-Ratio Determination in Contact Binaries

In the wake of recent theoretical work on contact systems (e.g. Whelan, 1972; Biermann and Thomas, 1972; Lucy, 1968), it is of importance to determine fundamental data from observations. This has been done recently by several groups in analysing light curves (Mochnacki and Doughty, 1972; Hutchings and Hill, 1973; Wilson and Devinney, 1973), and it is found that shapes, temperature differences and distributions, and mass-ratios, can be determined in many cases. However, where spectroscopic data are also available, the mass-ratios are not always in agreement. Using the photometric models, it is possible (Hutchings, 1973) to calculate the distortion of line profiles resulting (primarily) from the non-uniform brightness over the component stars in these systems. This distortion leads to the characteristically observed ‘square’ velocity curves for the systems (e.g. Binnendijk, 1967). Correction for the effect in most cases (a) resolves the mass-ratio discrepancy and (b) leads to better estimates for the masses. The faintness of most contact systems makes detailed spectroscopy difficult, but there appears to be a need for further work in the directions outlined here to improve the fundamental data available on them. These results should also be borne in mind in inspecting previous work on contact binaries.

The least-squares determination of mass ratios of spectroscopic binaries.

The least-squares determination of mass ratios of spectroscopic binaries.

On the Reduction of Photographic Star Positions and Proper Motions.

view Abstract Citations References Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS On the Reduction of Photographic Star Positions and Proper Motions. Eichhorn, Heinrich K. Abstract It is shown that a considerable increase in systematic accuracy can be obtained in photographic position work by eliminating the systematic errors which result between the positions of the same stars as obtained from overlapping plates with different centers. Technically, a strict least-squares solution for this problem will necessitate the solution of a system where the number of unknown coordinates is equal to the total number of stars plus the number of stars times plate constants. This method lends itself particularly well to the reduction of photographic star catalogues. A rigorous solution of this system can be easily and practically obtained by iterations which will always converge. Theoretical investigations show that the accuracy to be expected from a solution of that kind can be predicted under the assumption of a smooth distribution of stars. The application of this principle (the practical application of which requires an electronic computer) to parallax work not only increases the accuracy of the parallaxes thus obtained, but also yields accurate positions and motion of the comparison stars, which are very often urgently needed for the determination of mass ratios if observation series from different instruments are to be combined in one solution. Publication: The Astronomical Journal Pub Date: 1960 DOI: 10.1086/108131 Bibcode: 1960AJ.....65R.488E full text sources ADS |

Determination of parallax and mass-ratio of Q Coronae Borealis

Determination of parallax and mass-ratio of Q Coronae Borealis

On the Determination of Mass Ratios of Spectroscopic Binaries.

On the Determination of Mass Ratios of Spectroscopic Binaries.

Photographic Determination of Mass Ratios of Visual Binaries

Photographic Determination of Mass Ratios of Visual Binaries