Abundances in the Uranium-Rich Star CS 31082-001

The recent discovery by Cayrel et al. of U in CS 31082-001 along with Os and Ir at greatly enhanced abundances but with [Fe/H]=-2.9 strongly reinforces the argument that there are at least two kinds of SNII sources for r-nuclei. One source is the high-frequency H events responsible for heavy r-nuclei (A>135) but not Fe. The H-yields calculated from data on other ultra-metal-poor stars and the sun provide a template for quantitatively predicting the abundances of all other r-elements. In CS 31082-001 these should show a significant deficiency at A<135 relative to the solar r-pattern. It is proposed that CS 31082-001 should have had a companion that exploded as an SNII H event. If the binary survived the explosion, this star should now have a compact companion, most likely a stellar-mass black hole. Comparison of abundance data with predicted values and a search for a compact companion should provide a stringent test of the proposed r-process model. The U-Th age determined by Cayrel et al. for CS 31082-001 is, to within substantial uncertainties, in accord with the r-process age determined from solar system data. The time gap between Big Bang and onset of normal star formation only allows r-process chronometers to provide a lower limit on the age of the universe.Comment: 5 pages, 1 figur

SS Ari: a shallow-contact close binary system

Two CCD epochs of light minimum and a complete R light curve of SS Ari are presented. The light curve obtained in 2007 was analyzed with the 2003 version of the W-D code. It is shown that SS Ari is a shallow contact binary system with a mass ratio $q=3.25$ and a degree of contact factor f=9.4(\pm0.8%). A period investigation based on all available data shows that there may exist two distinct solutions about the assumed third body. One, assuming eccentric orbit of the third body and constant orbital period of the eclipsing pair results in a massive third body with $M_3=1.73M_{\odot}$ and P_3=87.0$yr. On the contrary, assuming continuous period changes of the eclipsing pair the orbital period of tertiary is 37.75yr and its mass is about$0.278M_{\odot}$. Both of the cases suggest the presence of an unseen third component in the system.Comment: 28 pages, 9 figures and 5 table

High Fill-Out, Extreme Mass Ratio Overcontact Binary Systems. X. The new discovered binary XY Leonis Minoris

The new discovered short-period close binary star, XY LMi, was monitored photometrically since 2006. It is shown that the light curves are typical EW-type and show complete eclipses with an eclipse duration of about 80 minutes. By analyzing the complete B, V, R, and I light curves with the 2003 version of the W-D code, photometric solutions were determined. It is discovered that XY LMi is a high fill-out, extreme mass ratio overcontact binary system with a mass ratio of q=0.148 and a fill-out factor of f=74.1%, suggesting that it is on the late evolutionary stage of late-type tidal-locked binary stars. As observed in other overcontact binary stars, evidence for the presence of two dark spots on both components are given. Based on our 19 epoches of eclipse times, it is found that the orbital period of the overcontact binary is decreasing continuously at a rate of dP/dt=-1.67\times10^{-7}\,days/year, which may be caused by the mass transfer from the primary to the secondary or/and angular momentum loss via magnetic stellar wind. The decrease of the orbital period may result in the increase of the fill-out, and finally, it will evolve into a single rapid-rotation star when the fluid surface reaching the outer critical Roche Lobe.Comment: 19 pages, 4 figures, 9 table

Kinematics and flux evolution of superluminal components in QSO B1308+326

Search for Doppler-boosting effect in flux evolution of superluminal components in blazars has been an important subject, which can help clarify their kinematic and emission properties. The kinematics and flux evolution observed at 15GHz for the three superluminal components (knot-c, -i and -k) in QSO B1308+326 (z=0.997) were investigated in detail. It is shown that the precessing jet nozzle model previously proposed by Qian et al. (1991, 2014, 2017, 2022a, 2022b) can be used to fully simulate their kinematics on pc-scales with a nozzle precession period of 16.9 yr. With the acceleration/deceleration in their motion found in the model-simulation of their kinematics we can derive their bulk Lorentz factor and Doppler factor as function of time and predict their Doppler-boosting effect. Interestingly, the flux evolution of the three superluminal components can be well interpreted in terms of their Doppler-boosting effect. The full explanation of both their kinematic behavior and flux evolution validates our precessing nozzle model and confirms that superluminal components are physical entities moving relativistically toward us at small viewing angles.Comment: 13 pages, 41 figure

Flux evolution and kinematics of superluminal components in blazar 3C345

The precessing jet-nozzle scenario previously proposed was applied to model-fit the kinematics of five superluminal components (C19,C20,C21,B5 and B7) of jet-B in blazar 3C345. Based on a specific pattern for the the precessing common trajectory of jet-B, the kinematic properties (including trajectory,coordinates, core separation and apparent velocity) were model-fitted and their flux evolution could be studied. Through model-simulation of their kinematic behavior, the bulk Lorentz factor, viewing angle and Doppler factor were derived as continuous functions of time and the association of their flux evolution with their Doppler-boosting effect was investigated. The 43GHz light-curves of the five superluminal components can be well interpreted in terms of their Doppler effect. The close association of their flux evolution with the Doppler-boosting effect firmly validates our precessing nozzle scenario and supports the traditional point-view that superluminal components are physical entities (traveling shocks or plasmoids) participating relativistic motion toward us at small angles. The model-simulation of kinematic behavior of superluminal components by using our precessing nozzle scenario with specific patterns (helical or ballistic) assumed for the precessing common trajectories yields the model-derived bulk Lorentz factor, apparent velocity, viewing angle and Doppler factor as continuous functions of time, which are most applicable to study the connection of flux evolution with Doppler boosting effect for the superluminal components.Comment: 18 pages and 63 figure

On a precessing jet-nozzle scenario with a common helical trajectory-pattern for blazar 3C345

The kinematics and flux evolution of the superluminal knots in blazar 3C345 were interpreted in the framework of the precessing jet-nozzle scenario with a precessing common helical trajectory-pattern. We show that the jet in 3C345 precesses with a period of 7.3yr and the superluminal knots move consistently along a precessing common helical trajectory-pattern in their inner jet regions, which can extend to core distances of about 1.2mas or traveled distances of about 300pc (for knots C4 and C9). Through model-fitting of the observed kinematic behavior of the superluminal knots, their bulk Lorentz factor and Doppler factor were derived as continuous functions of time, which were used to investigate their flux evolution. We found that the light curves measured at 15, 22 and 43GHz can be well model-fitted in terms of their Doppler boosting profiles associated with their superluminal motion. Flux fluctuations on shorter time scales also exist due to knots' intrinsic variations in flux density and spectral index. The close association of the flux evolution with the Doppler boosting effect is important, firmly vadidating the precessing jet-nozzle scenario being fully appropriate to explain both the kinematics and emission properties of the superluminal knots in 3C345. We have proposed both the precessing jet-nozzle scenarios with a single jet and double jets (this paper and Qian[2022b]) to understand the VLBI phenomena in 3C345. VLBI-observations with higher resolutions deep into the core regions (core distances less than 0.1mas) are required to test them.Comment: 21 pages, 68 figure