AD Cancri: A shallow contact solar-type eclipsing binary and evidence for a dwarf third component and a 16 year magnetic cycle

	AD Cancri: A shallow contact solar-type eclipsing binary and evidence for a dwarf third component and a 16 year magnetic cycle
	Qian SB(钱声帮)1,2 ; Yuan JZ(袁金照)1,2,3 ; Soonthornthum, B 4; Zhu LY(朱俐颖)1,2,3 ; He JJ(何家佳)1,2,3 ; Yang YG(杨远贵)1,2,3
刊名	ASTROPHYSICAL JOURNAL
	2007-12-10
卷号	671 期号:1 页码:811-820
关键词	binaries : close binaries : eclipsing stars : individual (AD Cancri) stars : magnetic fields
ISSN号	0004-637X
通讯作者	Qian, SB (reprint author), Chinese Acad Sci, Natl Astron Observ, Yunnan Observ, PO Box 110, Kunming 650011, Peoples R China.
产权排序	第一完成单位
英文摘要	CCD photometric observations of AD Cancri obtained from 2000 March 7 to 2004 December 20 are presented. Variations of the light levels at the primary minimum and both maxima are found. Uniform solutions of four sets of photometric data were derived by using the Wilson-Devinney method. The solutions suggest that AD Cancri is a shallow W-type contact binary (f 8.3% +/- 1.3%) with a highmass ratio of 1/q = 0.770 +/- 0.002. The long-term variation of the light curve is explained by variable dark-spot models of the more massive component star with a possible 17 yr cycle. Our 13 times of light minimum over 5 years, including others collected from the literature, have been used for the period study. The complex period changes can be sorted into a long-term period increase at rate of dP/dt +(4.94 +/- 0.16) x 10(-7) days yr(-1), a 16.2 yr periodic component (A(3) = 0.0155 days), and a very small amplitude period oscillation (A(4) = 0.0051 days, P-4 = 6.6 yr). The existence of third light may indicate that there is a tertiary component in the binary system. Solving the four-band light curves of Samec & Bookmyer, it is found that the contribution of the tertiary component to the total light of the triple system increases with wavelength, which suggests that it is very cool and may be a very red main-sequence star. The small-amplitude period oscillation may be caused by the light-time effect of the cool tertiary component (M-3 similar to 0.41 M-circle dot). The 16.2 yr periodic component in the orbital period and the 17 yr cyclic activity of the dark spot on the more massive component both may reveal that the more massive component displays solar-type magnetic activity with a cycle length of about 16 yr.
学科主题	Astronomy & Astrophysics
WOS标题词	Science & Technology ; Physical Sciences
类目[WOS]	Astronomy & Astrophysics
研究领域[WOS]	Astronomy & Astrophysics
关键词[WOS]	THERMAL RELAXATION OSCILLATION ; ORBITAL PERIOD MODULATION ; LIGHT-CURVE ANALYSIS ; OVERCONTACT BINARY ; ADDITIONAL COMPONENTS ; CLOSE BINARIES ; MASS-RATIO ; LEONIS ; ERIDANI ; SYSTEMS
收录类别	SCI
原文出处	http://iopscience.iop.org/0004-637X/671/1/811/
语种	英语
WOS记录号	WOS:000253331400069
内容类型	期刊论文
源URL	[http://ir.ynao.ac.cn/handle/114a53/5794]
专题	云南天文台_双星与变星研究组
作者单位	1.National Astronomical Observatories/Yunnan Observatory, Chinese Academy of Sciences, P.O. Box 110, 650011 Kunming, China 2.United Laboratory of Optical Astronomy, Chinese Academy of Sciences, 100012 Beijing, China 3.Graduate School of the Chinese Academy of Sciences, 100012 Beijing, China 4.Department of Physics, Faculty of Science, Chiang Mai University, Chiang Mai 50200, Thailand
推荐引用方式 GB/T 7714	Qian SB,Yuan JZ,Soonthornthum, B,et al. AD Cancri: A shallow contact solar-type eclipsing binary and evidence for a dwarf third component and a 16 year magnetic cycle[J]. ASTROPHYSICAL JOURNAL,2007,671(1):811-820.
APA	Qian SB,Yuan JZ,Soonthornthum, B,Zhu LY,He JJ,&Yang YG.(2007).AD Cancri: A shallow contact solar-type eclipsing binary and evidence for a dwarf third component and a 16 year magnetic cycle.ASTROPHYSICAL JOURNAL,671(1),811-820.
MLA	Qian SB,et al."AD Cancri: A shallow contact solar-type eclipsing binary and evidence for a dwarf third component and a 16 year magnetic cycle".ASTROPHYSICAL JOURNAL 671.1(2007):811-820.