Steward Observatory
Recent Submissions
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The Emission Lines in the Vicinity of Hydrogen Alpha in dMe Flare Star SpectraHigh resolution spectral data obtained in the vicinity of hydrogen alpha have been obtained for a number of dMe stars. Centrally reversed Ha emission profiles appear to be a general feature of dMe spectra. Possible mechanisms related to solar phenomena are discussed for forming this type of profile.
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Discrete States of Redshift and Galaxy Dynamics. III. Abnormal Galaxies and StarsThe redshift pattern in M82 is shown to be consistent with the multiple redshift concept as are redshift differentials in other active objects. The presence of multiple redshift states and the general lack, therefore, of violent motion appears consistent with all types of galaxies. Within our own Galaxy evidence is examined for effects of multiple redshift effects in stars. Four possibilities are considered; interstellar material, pre main sequence objects, rotation In massive stars, and highly evolved or peculiar stars. All classes show evidence of the predicted redshift periodicity. Stellar rotation in particular, is shown to occur preferentially in steps of 72.5 km s-1. Implications of the correlations are briefly discussed.
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Discrete States of Redshift and Galaxy Dynamics. II. Systems of GalaxiesIn the first paper in this series, a basic model was developed, for individual galaxies, consisting of two expanding opposed streams of material differing systematically in redshift. I.n this paper, galaxies in pairs and groups are shown to show no evidence of gravitational interaction. Redshift differentials between pairs of galaxies and between galaxies in clusters are found to take on preferred values which are various multiples of a basic 72.5 km s-1. There is also direct evidence that the redshift periodicity phases together between groups to imply that there is also no large scale motion between clusters of galaxies. The various mass discrepancies or peculiarities arising from a dynamical interpretation of differential redshifts are also shown to be of a form that no gravitational interaction and no significant motion requires.
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Galaxies, The Redshift, and GravityWhen apparent velocities of galaxies in clusters, measured by the red - shift, are correlated against magnitude and morphology, strong non -dynamical correlations emerge. The details of the correlations are used to develop a logical theory for the existance of multiple substates of matter, presumably involving the substructure of fundamental particles. Transitions between substates in a time systematic sense are presumed to occur under the ultimate conditions existant in the cores of black holes in galaxy nuclei. Subsequent separation of states and the interrelations between galaxies require that different substates of matter be non -interactive gravitationally.
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Are All Blue Stragglers Binaries?Radial velocity studies for five bright blue stragglers are reported and cluster membership is confirmed for four of them. Two of the stars show no significant radial velocity variations on a timescale of about 75 days and two others show no significant variation on timescales of 15 and 30 days respectively. The star for which cluster membership is uncertain may be a velocity variable. The data do not support the theory of blue straggler production involving mass transfer in a close binary. A spread in formation time of the stars in a cluster is shown to be a plausible explanation of the blue stragglers studied.
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G 240-72 -- A New Magnetic White Dwarf with Unusual PolarizationGD 240 72 ( =LP44 -113), a DC white dwarf, is found to show elliptical polarization. There is no evidence of variability. The circular component, typically 0.5 %,changes sign with wavelength, being negative in blue light a and positive in red. There is /relatively strong component of linear polarization, 1.4% in blue light.
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The Effects of the 35 Day X-Ray Cycle on the Light Curve of HZ HerculisWe report extensive photoelectric UBV photometry of the variable star HZ Her, originally undertaken to discover possible correlations between variations in its 1.7 day light curve and the 35 day cycle of the X -ray source Her X -1. Correlations recently reported by other groups are confirmed. These, as well as other features observed, are provisionally analyzed using a model consisting of a primary star, filling its Roche lobe and being illuminated by X -rays. The X -rays are emitted in a beam fixed in a rotating, precessing, neutron star secondary. Additional light is being contributed by material being transferred from the primary to the secondary.
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A Comparison of Variable and Non-Variable Stars in the Cepheid StripSpectra of three Cepheids (RX Aur, X Cyg and T Mon) and 11 non -variable supergiants are analyzed. Additional evidence is presented for the presence of non -variables within the Cepheid strip. Temperatures determined from Ha line profiles and broad band photometry were used together with model atmospheres and line strengths from the spectra to determine the gravities, turbulent velocities and element abundances. The gravities of the Cepheids appear to be lower than for the non -variables at the same luminosity while the turbulent velocities are higher. No differences of significance are found in the element abundances. The gravity differences can be explained either in terms of mass loss in the Cepheids or very low helium abundance in the non -variables. The former interpretation fails to explain why some Cepheid strip stars do not vary while the latter raises problems in connection with the origin of the elements. If we assume that pulsation causes some mass loss a more consistent picture emerges in which only moderate helium deficiencies are required in the non-variables.
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Fine Structure Within the Redshift-Magnitude Correlation for Galaxies : Proceedings of the 58th IAU Symposium (1973)Previous work on the redshift- magnitude banding correlation is briefly reviewed. New tests of the concept are applied successfully to a second cluster (A2199) and the outer portions of the Coma cluster. Using more than 200 redshifts in Coma, Perseus, and A2199 the presence of a distinct band - related- periodicity in redshift is indicated. Finally, a new sample of accurate redshifts of bright Coma galaxies on a single band is presented, which shows a strong redshift periodicity of 220 km sec -1. An upper limit of 20 km sec -1 is placed on the internal Doppler component of motion in the Coma cluster. Redshift- magnitude bands are, therefore, now recognized to consist of discrete "spin states" organized into "spin groups" which show strong mor- phological associations. Bands are probably in turn organized into band systems. The individual spin states are suggested to represent distinct configurations of matter at the nuclear or fundamental particle structure level. Transitions between states in a time systematic sense of decreasing redshift (increasing internal binding) is suggested to occur in galaxy nuclei. Energy released in such transitions is suggested as the driving energy in radio sources and related objects.
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Diffraction Effects in Pulsating Radio SourcesA pulsar radio emission model is developed to explore the effects of diffraction on pulsar beaming. At very low frequencies (y < 10 MHz), we predict an increase of pulse width and the discovery of new pulsars. The pulse width increase would be very difficult to untangle from interstellar scintillation effects. Observation of these diffraction effects would place restrictions on the size and radius of curvature of the emission regions.
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The Definition, Visibility, and Significance of Redshift-Magnitude BandsRedshift- magnitude bands as they occur in the Coma cluster are formally defined and the original bands as observed in 1972 are shown to have a likelihood of random occurance of only 0.005 independent of their direction. The properties of the Coma bands are transformed to m_p magnitudes and used to show that an independent sample of outlying Coma galaxies shows strong band related characteristics. The proper- ties of the Coma bands are then used to predict band properties for the A2199 cluster. The resultant power spectrum test of a preliminary A2199 sample shows agreement which has a random likelihood of occurance of only 0.001. The A2199 cluster also shows a band related morphological separation as in Coma.
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Polarization and Structure of the Crab Nebula : Proceedings of the 23rd IAU ColloquiumPresent knowledge of the optical, radio and X -ray polarization of the Crab is reviewed and discussed as it bears on the structure of the magnetic field, time scales in the nebula, and relations between nebula and pulsar. Not as much high -resolution polarimetry has been done on the Crab as might have been expected. Loops of field and a large -scale structure can be recognized, but it is not known whether the fields generally are smooth or chaotic on a small scale. Field lines tend to curl around the filaments. The large angular size of the X -ray source poses a difficulty to conventional theory. The form of the nebula does not single out the pulsar as its source, and the exact relation between pulsar and nebula is uncertain. The wave -field or "synchro- Compton" interpretation of the continuum emission is erroneous but has led to interesting observations of circular polarization. Circular polarization of the ordinary synchrotron radiation might be observable in the radio band. Magnetic flux may have been generated in the nebula by winding of lines around the rotating pulsar. Polaroid photographs then suggest that the pulsar rotation axis is roughly NW -SE, but confirmation is lacking.
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X-Ray Beaming and Mass Transfer in HZ HerThe optical and X -ray properties of HZ Her are analyzed within the framework of a model in which the primary is illuminated by X -ray radiation from a degenerate secondary companion. System parameters are derived on the basis of a simplified model and yield a minimum distance to HZ Her of - 5 kpc. It is shown that the X -ray pulses and 35 day on -off characteristics as well as the shape and modulation of the optical light curve can be understood if (i) the primary is illuminated by X -ray emitted in a beam fixed in a rotating neutron star secondary undergoing forced precession and (ii) energy is supplied by mass transfer from primary to secondary resulting in the formation of a disc around the X -ray source which contributes significantly to the total light.
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Stimulated Linear Acceleration Radiation: A Pulsar Radio Emission MechanismThe Einstein coefficient method is used to calculate the absorption coefficient K for a steady flux of electrons undergoing acceleration in a uniform electric field. Under the approximation that the motion is ultrarelativistic, the emission frequency is low, and the emission direction is nearly parallel to the direction of motion, we find that K is negative for certain emission directions. The formalism is applied to pulsars, and it is shown that strong maser action is expected. If the emission takes place near the velocity -of -light cylinder, the computed collisional Bremsstrahlung may be strong enough to produce the recently observed high- energy Y -rays.
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Conditions for Carbon Monoxide Vibration-Rotation LTE in Late StarsCollisional vibration and rotation transition rates are found for carbon monoxide due to H, H2, He and electrons. These rates are compared to the radiative rates of transition in carbon monoxide to establish temperature -pressure regions in which Vibration -Rotation LTE is a good approximation and those regions in which possible non -LTE effects may occur. Comparison of these data with current late star model atmospheres indicates that possible vibrational non -LTE effects may occur in supergiants, but in all late star computed atmospheres rotational LTE should be a good approximation. The further question of total molecular LTE is examined and rate equations set up. Rough order of magnitude estimates are made on the conditions for total LTE in CO.