The light curve analyses and orbital period variations for two contact binary stars,LS Del and V997 Cyg,are presented in this work which was conducted in the frame of the Binary Systems of South and North project Grou...The light curve analyses and orbital period variations for two contact binary stars,LS Del and V997 Cyg,are presented in this work which was conducted in the frame of the Binary Systems of South and North project Ground-based photometric observations were performed at two observatories in France.We used the Transiting Exoplanet Survey Satellite(TESS)data for extracting times of minima and light curve analysis of the targe systems.The O-C diagram for both systems displays a parabolic trend.LS Del and V997 Cyg’s orbital periods are increasing at rates of dP/dt=7.20×10^(-08)days yr^(-1)and dP/dt=2.54×10^(-08)days yr^(-1),respectively Therefore,it can be concluded that mass is being transferred from the less massive star to the more massive component with a rate of dM/dt=-1.96×10^(-7)M_(⊙)yr^(-1)for the LS Del system,and dM/dt=-3.83×10^(-7)M_(⊙)yr-1for V997 Cyg.The parameters of a third possible object in the system are also considered.The PHysics Of Eclipsing BinariEs Python code was used to analyze the light curves.The light curve solutions needed a cold starspot due to the asymmetry in the LS Del system’s light curve maxima.The mass ratio fill-out factor,and star temperature all indicate that both systems are contact binary types in this investigation.Two methods were applied to estimate the absolute parameters of the systems:one method relied on the parallax of Gaia DR3,and the other used a P-M relationship.The positions of the systems are also depicted on the M-L,M-R q-L_(ratio),and logM_(tot)-logJ_(0)diagrams.We recommend that further observations and investigations be done on the existence of a fourth body in this system.展开更多
为了降低研发风险,对eVTOL项目产品化指数问题进行了研究。采用改进的新产品评估指标体系,并利用灰色关联-最小二乘(GC-LS)法得到eVTOL项目产品化指数。该方法有效地减弱了产品化指数模型与层次分析法(AHP)中主观性的影响。对15款已公...为了降低研发风险,对eVTOL项目产品化指数问题进行了研究。采用改进的新产品评估指标体系,并利用灰色关联-最小二乘(GC-LS)法得到eVTOL项目产品化指数。该方法有效地减弱了产品化指数模型与层次分析法(AHP)中主观性的影响。对15款已公开的电动垂直起降飞行器(electric Vertical Take-Off and Landing,eVTOL)项目产品化指数进行了估计,其中14款用于确定最优权重,1款用于检验最优权重下的估计准确性。结果:1)最优权重下的估计结果与实际情况吻合较好。2)最优权重排名前三的为研发进度、安全性和社会接受度。结论:1)GC-LS法给出的最小二乘最优权重比较合理。2)研发进度、安全性和社会接受度三个要素对eVTOL项目产品化指数具有相对更重要的影响。3)利用GC-LS法可较方便准确地估计eVTOL项目的产品化指数。展开更多
基金project was supported by the Scientific Research Projects Coordination Unit of Erciyes University(project number FBA-2022-11737)the TESS mission is provided by the NASA Explorer Program。
文摘The light curve analyses and orbital period variations for two contact binary stars,LS Del and V997 Cyg,are presented in this work which was conducted in the frame of the Binary Systems of South and North project Ground-based photometric observations were performed at two observatories in France.We used the Transiting Exoplanet Survey Satellite(TESS)data for extracting times of minima and light curve analysis of the targe systems.The O-C diagram for both systems displays a parabolic trend.LS Del and V997 Cyg’s orbital periods are increasing at rates of dP/dt=7.20×10^(-08)days yr^(-1)and dP/dt=2.54×10^(-08)days yr^(-1),respectively Therefore,it can be concluded that mass is being transferred from the less massive star to the more massive component with a rate of dM/dt=-1.96×10^(-7)M_(⊙)yr^(-1)for the LS Del system,and dM/dt=-3.83×10^(-7)M_(⊙)yr-1for V997 Cyg.The parameters of a third possible object in the system are also considered.The PHysics Of Eclipsing BinariEs Python code was used to analyze the light curves.The light curve solutions needed a cold starspot due to the asymmetry in the LS Del system’s light curve maxima.The mass ratio fill-out factor,and star temperature all indicate that both systems are contact binary types in this investigation.Two methods were applied to estimate the absolute parameters of the systems:one method relied on the parallax of Gaia DR3,and the other used a P-M relationship.The positions of the systems are also depicted on the M-L,M-R q-L_(ratio),and logM_(tot)-logJ_(0)diagrams.We recommend that further observations and investigations be done on the existence of a fourth body in this system.
文摘为了降低研发风险,对eVTOL项目产品化指数问题进行了研究。采用改进的新产品评估指标体系,并利用灰色关联-最小二乘(GC-LS)法得到eVTOL项目产品化指数。该方法有效地减弱了产品化指数模型与层次分析法(AHP)中主观性的影响。对15款已公开的电动垂直起降飞行器(electric Vertical Take-Off and Landing,eVTOL)项目产品化指数进行了估计,其中14款用于确定最优权重,1款用于检验最优权重下的估计准确性。结果:1)最优权重下的估计结果与实际情况吻合较好。2)最优权重排名前三的为研发进度、安全性和社会接受度。结论:1)GC-LS法给出的最小二乘最优权重比较合理。2)研发进度、安全性和社会接受度三个要素对eVTOL项目产品化指数具有相对更重要的影响。3)利用GC-LS法可较方便准确地估计eVTOL项目的产品化指数。
