Greatly Enhanced Eccentricity Oscillations in Quadruple Systems Composed of Two Binaries: Implications for Stars, Planets, and Transients
Ondrej Pejcha, Joe M. Antognini, Benjamin J. Shappee, Todd A. Thompson
备注：
8 pages, 5 figures, 1 table. Accepted to MNRAS. Added a figure showing the distribution of binary inclinations at the moment of collision. For a brief video explaining the key results of this paper, see http://youtu.be/x3xArX667r8
We study the orbital evolution of hierarchical quadruple systems composed of two binaries on a long mutual orbit, where each binary acts as a Kozai-Lidov (KL) perturber on the other. We find that the coupling between the two binaries qualitatively changes the behavior of their KL cycles. The binaries can experience coherent eccentricity oscillations as well as excursions to very high eccentricity that occur over a much larger fraction of the parameter space than in triple systems. For a ratio of outer to inner semi-major axes of 10 to 20, about 30 to 50% of equal-mass quadruples reach eccentricity 1-e < 10^{-3} in one of the binaries. This is about 4 to 12 times more than for triples with equivalent parameters. Orbital "flips" and collisions without previous tidal interaction are similarly enhanced in quadruples relative to triples. We argue that the frequency of evolutionary paths influenced by KL cycles is comparable in the triple and quadruple populations even though field quadruples are a factor of ~5 less frequent than triples. Additionally, quadruples might be a non-negligible source of triples and provide fundamentally new evolutionary outcomes involving close binaries, mergers, collisions, and associated transients, which occur without any fine tuning of parameters. Finally, we study the perturbations to a planetary orbit due to a distant binary and we find that the fraction of orbital flips is a factor of 3 to 4 higher than for the corresponding triple system given our fiducial parameters with implications for hot Jupiters and star-planet collisions.
Quadruple system HD 135160 in a unique 2+2 configuration
Astronomical Institute of Charles University, Faculty of Mathematics and Physics（查理大学数学物理学院天文研究所）；University of North Carolina at Chapel Hill（北卡罗来纳大学教堂山分校）；High Point University（海普特大学）；Variable Stars South, Congarinni Observatory（变星南天观测站孔加里尼天文台）；European Organisation for Astronomical Research in the Southern Hemisphere (ESO)（欧洲南方天文台）
TIC 433545934: The first 2+2 type doubly eclipsing binary with extra, mutual eclipses
HUN–REN–SZTE Stellar Astrophysics Research Group（匈牙利科学院-罗兰大学恒星天体物理学研究组）；Baja Astronomical Observatory of University of Szeged（塞格德大学巴亚天文台）；Konkoly Observatory, Research Centre for Astronomy and Earth Sciences（孔科利天文台，地球与天文学研究中心）；Department of Physics, Kavli Institute for Astrophysics and Space Research, M.I.T.（麻省理工学院物理系，卡弗里天体物理学与空间研究研究所）；Astronomical Institute, Faculty of Mathematics and Physics, Charles University（查理大学数学与物理学院天文研究所）；FZU - Institute of Physics of the Czech Academy of Sciences（捷克科学院物理研究所（FZU））；Research Centre for Theoretical Physics and Astrophysics, Institute of Physics, Silesian University in Opava（奥帕瓦西里西亚大学物理研究所理论物理与天体物理学研究中心）；Astronomical Institute, Academy of Sciences（科学院天文研究所）；Department of Experimental Physics, University of Szeged（塞格德大学实验物理系）
Eccentric millisecond pulsar + subdwarf B star from rotationally delayed accretion-induced-collapse scenario
International Centre of Supernovae (ICESUN), Yunnan Key Laboratory of Supernova Research, Yunnan Observatories, Chinese Academy of Sciences (CAS)（国际超新星中心，云南省超新星研究重点实验室，中国科学院云南天文台）
