One model to rule them all: magnetic braking from CVs to low-mass stars

YNAO OpenIR > 大样本恒星演化研究组

	One model to rule them all: magnetic braking from CVs to low-mass stars
	Sarkar, Arnab 1; Ge HW(葛宏伟)2,3,4 ; Yungelson, Lev 5; Tout, Christopher A.1
会议录名称	Proceedings of Science
	2024-11-20
卷号	460
产权排序	第2完成单位
收录类别	EI
会议名称	6th Golden Age of Cataclysmic Variables and Related Objects, GOLDEN 2023
会议日期	2023-09-04
会议地点	Palermo, Italy
摘要	We present the results of the study of the secular evolution of donor stars in cataclysmic variables (CVs) and AM Canum Venaticorum (AM CVn) stars with our double dynamo (DD) formalism of angular momentum loss (AML) by magnetic braking (MB). In our DD model, MB is driven by an interplay between two a − Ω dynamos, one in the convective envelope and the other at the boundary of the radiative core and the convective envelope. We show that (1) our MB model reproduces the period gap (2 Porb/ hr 3) and the period minimum spike (Porb ≈ 80 min) in the distribution of non-magnetic CVs, (2) evolved CVs, where the donor star commences Roche lobe overflow (RLOF) close to or just beyond the end of the main-sequence, populate the region in and beyond the period gap, and are more likely to be detected at Porb ≥ 5.5 hr. This likely contaminates the mass-radius fit of long-period CV donors. We show that (3) some of the evolved CVs become AM CVn stars with 10 Porb/ min 65. Their evolution, driven by AMLMB and AML by gravitational radiation (GR, AMLGR), leaves them extremely H-exhausted to the point of being indistinguishable from AM CVn systems formed via the He-star and the White Dwarf (WD) channels in terms of the absence of H in their spectra. We further show that (4) owing to the presence of a significant radiative region, intermediate-mass giants/sub-giants, which are progenitors of AM CVn stars formed through the He-star channel, may undergo common envelope evolution that does not behave classically, (5) several AM CVn systems with extremely bloated donors, such as Gaia14aae, ZTFJ1637+49 and SRGeJ045359.9+622444 do not match any modelled trajectories if these systems are modelled only with AMLGR without incorporating AMLMB, (6) the uncertainties in MB estimates greatly affect modelling results. This, in turn, affects our efforts to distinguish between different AM CVn formation channels and their relative importance. Finally, we find that (7) a similar MB prescription also explains the spin-down of single, low-mass stars. © Copyright owned by the author(s)
资助项目	National Key Research and Development Program of China[2021YFA1600403]
项目资助者	National Key Research and Development Program of China[2021YFA1600403]
语种	英语
学科领域	天文学 ; 恒星与银河系
文章类型	Conference article (CA)
EI入藏号	20244917492930
EI主题词	White dwarfs
EI分类号	1201.8 - 1301.1.3 - 1301.1.5 - 1301.2.1.1.1 - 1302.1.2 - 212.3 - 301.1 - 301.1.3 - 651 Aerodynamics
文献类型	会议论文
条目标识符	http://ir.ynao.ac.cn/handle/114a53/27859
专题	大样本恒星演化研究组中国科学院天体结构与演化重点实验室
作者单位	1.Institute of Astronomy, University of Cambridge, The Observatories, Madingley Road, Cambridge, CB3 OHA, United Kingdom; 2.Yunnan Observatories, Chinese Academy of Sciences, Kunming, 650216, China; 3.Key Laboratory for Structure and Evolution of Celestial Objects, CAS, Kunming, 650216, China; 4.International Centre of Supernovae, Yunnan Key Laboratory, Kunming, 650216, China; 5.Institute of Astronomy, The Russian Academy of Sciences, 48 Pyatnitskaya Str., Moscow, 119017, Russia
推荐引用方式 GB/T 7714	Sarkar, Arnab,Ge HW,Yungelson, Lev,et al. One model to rule them all: magnetic braking from CVs to low-mass stars[C],2024.