| 其他摘要 | Eclipsing Am binaries are the eclipsing binaries consisting of Am type chemically peculiar star.Chemically Peculiar Stars（ CP stars） are the stars with abnormal strong or weak spectral lines of some elements, the formation and evolution of which are always open questions in astrophysics. Most CP stars are main sequence A and B type stars. The main classification of CP star shouldbe Am star, magnetic CP star, Hg-Mn star and He-abnormal star. CP starsalso consist of some triple even quadruple systems. Am star shows the highestbinaries percentage (up to 90% or higher), and many Am stars are found in eclipsing binaries. As we all know, eclipsing binary is a significant way to obtainthe fundamental physical parameters of stars, such as mass,radius and others,so photometric observation and analysis of eclipsing Am binaries can derive thephysical parameters,mass transfer and other information of Am star, which willpromote the investigation of CP stars effectively. A brief overview and researchprogress of CP stars were given in this paper. In 2009, Renson & Manfroid reported a catalogue of Am and Ap stars with 73 eclipsing Am binaries inside.Basing on this,we make investigation and survey about the eclipsing Am binaries, and obtain a more complete catalogue of eclipsing Am binaries currently.Two eclipsing Am binaries with periods shorter than 1 day were chose as ourtargets: V1073Cyg and TYC6408-989-1. According to the result of investigationand combining with the observation light curves and the orbital analysis, theconclusions are shown as follow: 1. We made a supplement to the catalogue of eclipsing Am binaries referringto the correlatable papers so far, another 17 eclipsing Am binaries were foundand listed in the supplement table with period and spectral type. The statisticalanalysis about the periods of eclipsing Am binaries showed that the peak of theperiods distribution was 2-4 days, which concentrative distributed in 2-3 days.Few binaries’ periods were longer than 20 days or shorter than 1 days. There areonly four systems with period in 1 days: TYC6408-989-1, V1073Cyg, V2787Ori and IW Per, and IW Per comes from the supplement catalogue of eclipsing Ambinaries. 2.For the W Uma type eclipsing Am binary V1073Cyg, photometric observation together with the analysis of light curve and orbital period lead to that theorbital period of V1073Cyg is decreasing continuously with P ˙ = ?4.91(±0.93) ×10?8d yr?1 superposed by a cyclic change. The period decrease can be causedby the synthetical effect of mass transfer between the components and angularmomentum loss. The cyclic change, of which the period is 84.52(±0.52)yrandthe semi-amplitude is 4.95(±0.42)AU, can be explained by the swing of binary'sbarycenter due to the existence of a third body with M3 = 0.488(±0.048)M⊙.Light curve analysis revealed that V1073Cyg is an over-contact system and about20% of the total luminosity comes from the third body. The light curve analysiswas consistent with the O ? C theoretical analysis for the third body very well,so we confirm that V1073Cyg should be a triple system. 3.The light curve of TYC6408-989-1 is EB type. For the first detailed photometric observation and investigation of this system, integrated V band lightcurve was acquire by the 70 cm telescope in Li-jiang station. The analysis of lightcurve can be carried out with W-D program in three modes, and the mass ratiowas in the range of 0.205-0.274. We can conjecture that TYC6408-989-1 may bea near contact binary. Further efforts will be made to require more observationdata in multiple bands of this system, so that we can accomplish more detailedinvestigation about this system. |
修改评论