ASAS J174406+2446.8 is identified as a marginal-contact binary with a possible cool third body  

作　　者：Xiang-Dong Shi Sheng-Bang Qian Lin-Jia Li Wei-Wei Na Xiao Zhou 

机构地区：[1]Yunnan Observatories,Chinese Academy of Sciences,Kunming 650216,China [2]University of Chinese Academy of Sciences,Beijing 100049,China [3]Key Laboratory of the Structure and Evolution of Celestial Objects,Chinese Academy of Sciences,Kunming 650216,China [4]Center for Astronomical Mega-Science,Chinese Academy of Sciences,Beijing 100101,China [5]Yuxi Normal University,Yuxi 653100,China

出　　处：《Research in Astronomy and Astrophysics》2020年第6期265-272,共8页天文和天体物理学研究（英文版）

基　　金：supported by the National Natural Science Foundation of China(Nos.11933008,11703080 and 11803084);the Yunnan Natural Science Foundation(No.2018FB006)。

摘　　要：ASAS J174406+2446.8 was originally found as aδScuti-type pulsating star with the period P=0.189068 d by ASAS survey.However,the LAMOST stellar parameters reveal that it is far beyond the red edge of pulsational instability strip on the log g-T diagram ofδScuti pulsating stars.To understand the physical properties of the variable star,we observed it by the 1.0-m Cassegrain reflecting telescope at Yunnan Observatories.Multi-color light curves in B,V,R_c and I_c bands were obtained and are analyzed by using the W-D program.It is found that this variable star is a shallow-contact binary with an EB-type light curve and an orbital period of 0.3781 d rather than aδScuti star.It is a W-subtype contact binary with a mass ratio of 1.135(±0.019)and a fill-out factor of 10.4%(±5.6)%.The situation of ASAS J174406+2446.8 resembles those of other EB-type marginal-contact binaries such as UU Lyn,ⅡPer and GW Tau.All of them are at a key evolutionary phase from a semi-detached configuration to a contact system predicted by the thermal relaxation oscillation theory.The linear ephemeris was corrected by using 303 new determined times of light minimum.It is detected that the O-C curve shows a sinusoidal variation that could be explained by the light-travel-time effect via the presence of a cool red dwarf.The present investigation reveals that some of theδScuti-type stars beyond the red edge of pulsating instability strip on the log g-T diagram are misclassified eclipsing binaries.To understand their structures and evolutionary states,more studies are required in the future.

关 键 词：STARS BINARIES close-stars BINARIES eclipsing-stars δScuti-stars individual(ASAS J174406+2446.8) 

分 类 号：P144[天文地球—天体物理]