Kato T.,Kyoto University |
Maehara H.,Kyoto University |
Uemura M.,Hiroshima University |
Henden A.,American Association of Variable Star Observers AAVSO |
And 57 more authors.
Publications of the Astronomical Society of Japan | Year: 2010
Continued from Kato et al. (2009, PASJ, 61, S395), we collected the times of superhump maxima for 68 SU UMa-type dwarf novae, mainly observed during the 2009-2010 season. The newly obtained data confirmed the basic findings reported in Kato et al. (ibid.): the presence of stages A-C and the predominance of positive period derivatives during stage B in systems with superhump periods shorter than 0.07 d. There was a systematic difference in the period derivatives for the systems with superhump periods longer than 0.075 d between this study and Kato et al. (ibid.). We suggest that this difference was possibly caused by a relative lack of frequently outbursting SU UMa-type dwarf novae in this period regime in the present study. We recorded a strong beat phenomenon during the 2009 superoutburst of IY UMa. A close correlation between the beat period and the superhump period suggests that the changing angular velocity of the apsidal motion of the elliptical disk is responsible for the variation of the superhump periods. We also described three new WZ Sge-type objects with established early superhumps and one with likely early superhumps. We suggest that two systems, VX For and EL UMa, are WZ Sge-type dwarf novae with multiple rebrightenings. The O -C variation in OT J213806.6+261957 suggests that the frequent absence of rebrightenings in very short-Porb objects can be the result of a sustained superoutburst plateau at the epoch when usual SU UMa-type dwarf novae return to quiescence, preceding a rebrightening. We also present a formulation for a variety of Bayesian extensions to traditional period analyses. © 2010. Astronomical Society of Japan. Source
Rodenas M.,Research Center del Medio Ambiente |
Dieguez J.J.,Polytechnic University of Valencia |
Perez-Garcia M.L.,Research Center del Medio Ambiente |
Lomba R.,Research Center del Medio Ambiente |
And 2 more authors.
Microchemical Journal | Year: 2012
Carbon disulfide (CS2), a relevant reduced sulfur compound in air, is well-known for its malodor and its significant effect on global atmospheric chemistry. Therefore, a reliable method for determining CS2 in atmospheric samples has been developed based on solid-phase sampling and gas chromatography-mass spectrometry (GC-MS). Two types of solid-phase sampling supports (Orbo-32 and SKC) and the elution with organic solvents - hexane and toluene - were evaluated for low-volume outdoor sampling. Recovery studies and the standard addition method were carried out to demonstrate the proper determination of CS2 in the absence of the influence of interferences such as ozone, hydrogen sulfide or water - important atmospheric pollutants. The proposed methodology was validated by performing experiments in a high-volume smog chamber and by comparison with two reference optical methods, Fourier Transform Infrared (FTIR) and Differential Optical Absorption Spectroscopy (DOAS) installed in these facilities. Satisfactory analytical parameters were reported: fast analysis, a correct repeatability of 6±1% and reproducibility of 14±3%, and low detection limits of 0.3-0.9pgm-3. Finally, the method was successfully applied to industrial samples near a pulp factory area, where a high correlation between industrial emissions and reported carbon disulfide concentrations were observed. © 2011 Elsevier B.V. Source