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

Bell violation for unknown continuous-variable states

We describe a new Bell test for two-particle entangled systems that engages an unbounded continuous variable. The continuous variable state is allowed to be arbitrary and inaccessible to direct measurements. A systematic method is introduced to perform the required measurements indirectly. Our results provide new perspectives on both the study of local realistic theory for continuous-variable systems and on the nonlocal control theory of quantum information.Comment: 8 pages, published versio

Evaluation of surface energy and radiation balance systems for FIFE

The energy balance and radiation balance components were determined at six sites during the First International Satellite Land Surface Climatology Project Field Experiment (FIFE) conducted south of Manhattan, Kansas during the summer of 1987. The objectives were: to determine the effect of slope and aspect, throughout a growing season, on the magnitude of the surface energy balance fluxes as determined by the Energy Balance Method (EBM); to investigate the calculation of the soil heat flux density at the surface as calculated from the heat capacity and the thermal conductivity equations; and to evaluate the performance of the Surface Energy and Radiation Balance System (SERBS). A total of 17 variables were monitored at each site. They included net, solar (up and down), total hemispherical (up and down), and diffuse radiation, soil temperature and heat flux density, air and wet bulb temperature gradients, wind speed and direction, and precipitation. A preliminary analysis of the data, for the season, indicate that variables including net radiation, air temperature, vapor pressure, and wind speed were quite similar at the sites even though the sites were as much as 16 km apart and represented four cardinal slopes and the top of a ridge

Extended mapping and characteristics techniques for inverse aerodynamic design

Some ideas for using hodograph theory, mapping techniques and methods of characteristics to formulate typical aerodynamic design boundary value problems are developed. The inverse method of characteristics is shown to be a fast tool for design of transonic flow elements as well as supersonic flows with given shock waves

Chemical Evolution of the Juvenile Universe

Only massive stars contribute to the chemical evolution of the juvenile universe corresponding to [Fe/H]<-1.5. If Type II supernovae (SNe II) are the only relevant sources, then the abundances in the interstellar medium of the juvenile epoch are simply the sum of different SN II contributions. Both low-mass (~8-11M_sun) and normal (~12-25M_sun) SNe II produce neutron stars, which have intense neutrino-driven winds in their nascent stages. These winds produce elements such as Sr, Y, and Zr through charged-particle reactions (CPR). Such elements are often called the light r-process elements, but are considered here as products of CPR and not the r-process. The observed absence of production of the low-A elements (Na through Zn including Fe) when the true r-process elements (Ba and above) are produced requires that only low-mass SNe II be the site if the r-process occurs in SNe II. Normal SNe II produce the CPR elements in addition to the low-A elements. This results in a two-component model that is quantitatively successful in explaining the abundances of all elements relative to hydrogen for -3<[Fe/H]<-1.5. This model explicitly predicts that [Sr/Fe]>-0.32. Recent observations show that there are stars with [Sr/Fe]<-2 and [Fe/H]<-3. This proves that the two-component model is not correct and that a third component is necessary to explain the observations. This leads to a simple three-component model including low-mass and normal SNe II and hypernovae (HNe), which gives a good description of essentially all the data for stars with [Fe/H]<-1.5. We conclude that HNe are more important than normal SNe II in the chemical evolution of the low-A elements, in sharp distinction to earlier models. (Abridged)Comment: 10 pages, 9 figures, to appear in Pub. Astron. Soc. Australi

Probing r-Process Production of Nuclei Beyond Bi209 with Gamma Rays

We estimate gamma-ray fluxes due to the decay of nuclei beyond Bi209 from a supernova or a supernova remnant assuming that the r-process occurs in supernovae. We find that a detector with a sensitivity of about 10**(-7) photons/cm**2/s at energies of 40 keV to 3 MeV may detect fluxes due to the decay of Ra226, Th229, Am241, Am243, Cf249, and Cf251 in the newly discovered supernova remnant near Vela. In addition, such a detector may detect fluxes due to the decay of Ac227 and Ra228 produced in a future supernova at a distance of about 1 kpc. As nuclei with mass numbers A > 209 are produced solely by the r-process, such detections are the best proof for a supernova r-process site. Further, they provide the most direct information on yields of progenitor nuclei with A > 209 at r-process freeze-out. Finally, detection of fluxes due to the decay of r-process nuclei over a range of masses from a supernova or a supernova remnant provides the opportunity to compare yields in a single supernova event with the solar r-process abundance pattern.Comment: 24 pages, 3 figures, to appear in the October 10, 1999 issue of Ap