http://chineseinput.net/에서 pinyin(병음)방식으로 중국어를 변환할 수 있습니다.
변환된 중국어를 복사하여 사용하시면 됩니다.
THE PROPOSED QUADRUPLE SYSTEM SZ HERCULIS: REVISED LITE MODEL AND ORBITAL STABILITY STUDY
Hinse, Tobias Cornelius,Goź,dziewski, Krzysztof,Lee, Jae Woo,Haghighipour, Nader,Lee, Chung-Uk American Institute of Physics 2012 The Astronomical journal Vol.144 No.2
<P>In a recent study, Lee et al. presented new photometric follow-up timing observations of the semidetached binary system SZ Herculis and proposed the existence of two hierarchical cirumbinary companions. Based on the light-travel time effect, the two low-mass M-dwarf companions are found to orbit the binary pair on moderate to high eccentric orbits. The derived periods of these two companions are close to a 2:1 mean-motion orbital resonance. We have studied the stability of the system using the osculating orbital elements as presented by Lee et al. Results indicate an orbit-crossing architecture exhibiting short-term dynamical instabilities leading to the escape of one of the proposed companions. We have examined the system's underlying model parameter space by following a Monte Carlo approach and found an improved fit to the timing data. A study of the stability of our best-fitting orbits also indicates that the proposed system is generally unstable. If the observed anomalous timing variations of the binary period is due to additional circumbinary companions, then the resulting system should exhibit a long-term stable orbital configuration much different from the orbits suggested by Lee et al. We, therefore, suggest that based on Newtonian-dynamical considerations, the proposed quadruple system cannot exist. To uncover the true nature of the observed period variations of this system, we recommend future photometric follow-up observations that could further constrain eclipse-timing variations and/or refine light-travel time models.</P>
New light‐travel time models and orbital stability study of the proposed planetary system HU Aquarii
Hinse, T. C.,Lee, J. W.,Goź,dziewski, K.,Haghighipour, N.,Lee, C.x2010,U.,Scullion, E. M. Blackwell Publishing Ltd 2012 Monthly notices of the Royal Astronomical Society Vol.420 No.4
<P><B>ABSTRACT</B></P><P>In this work we propose a new orbital architecture for the two proposed circumbinary planets around the polar eclipsing binary HU Aquarii. We base the new two‐planet, light‐travel time model on the result of a Monte Carlo simulation driving a least‐squares Levenberg–Marquardt minimization algorithm on the observed eclipse egress times. Our best‐fitting model with <IMG src='/wiley-blackwell_img/equation/MNR_20283_mu1.gif' alt ='inline image'/> resulted in high final eccentricities for the two companions leading to an unstable orbital configuration. From a large ensemble of initial guesses, we examined the distribution of final eccentricities and semimajor axes for different <IMG src='/wiley-blackwell_img/equation/MNR_20283_mu2.gif' alt ='inline image'/> parameter intervals and encountered qualitatively a second population of best‐fitting parameters. The main characteristic of this population is described by low‐eccentric orbits favouring long‐term orbital stability of the system. We present our best‐fitting model candidate for the proposed two‐planet system and demonstrate orbital stability over one million years using numerical integrations.</P>