2002, A.J., 576, 982) giant planets analogous to Jupiter and Saturn are included if their orbits are stable. The initial disk of planetary embryos is the same as that used for simulating the late stages of terrestrial planet growth within our Solar System and around individual stars in the Alpha Centauri system (Quintana et al. We have simulated the late stages of growth of terrestrial planets in both circumbinary disks around 'close' binary star systems with stellar separations ($ a_B$) in the range 0.05 AU $\\le a_B \\le$ 0.4 AU and binary eccentricities in the range $0 \\le e \\le 0.8$ and circumstellar disks around individual stars with binary separations of tens of AU. If planets form at the right places within such disks, they can remain dynamically stable for very long times.
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Disk material has been observed around one or both components of various young close binary star systems. Most stars reside in binary/multiple star systems however, previous models of planet formation have studied growth of bodies orbiting an isolated single star. Terrestrial Planet Formation in Binary Star Systems Comparison of our results with the prediction of evolutionary models support the observational evidence that theoretical models tend to slightly underestimate the mass of the low-mass stars. Conclusions: We show that the orbital motion of the AB Dor A/C system is remarkably well determined, leading to precise estimates of the dynamical masses. Comparisons with PMS stellar evolution models favor and age of 40-50 Myr for AB Dor A and of 25-120 Myr for AB Dor C. Results: The main star AB Dor A is clearly detected in all the VLBI observations, which allowed us to analyze the orbital motion of the system and to obtain model-independent dynamical masses of 0.90 ± 0.08 M⊙ and 0.090 ± 0.008 M⊙, for AB Dor A and AB Dor C, respectively. The astrometric information resulting from our observations was analyzed along with previously reported VLBI, optical (Hipparcos), and infrared measurements. Methods: We observed in phase-reference mode the binary AB Dor A/C, 0.2'' separation, with the Australian Long Baseline Array at 8.4 GHz.
Aims: We aim to revisit the dynamical masses of the components of AB Dor A/C to refine earlier comparisons between the measurements of stellar parameters and the predictions of stellar models. The well-known PMS binary AB Dor A/C is an important benchmark for this task, since it displays intense and compact radio emission, which makes possible the application of high-precision astrometric techniques to this system. The study of pre-main-sequence (PMS) stars with model-independent measurements of their masses is essential to check the validity of theoretical models of stellar evolution. The AB Doradus system revisited: The dynamical mass of AB Dor A/CĪzulay, R. Three example orbits with periods of 44.6, 180, and 310 yr are presented. When the position angle in some astrometric measurements was flipped by 180°, orbits with periods close to 45 yr are also plausible. An original criterion to establish the upper limit of the orbital period is applied. Otherwise, we find masses of, minimal orbital periods should begin at 105, 150, 335, and 2300 yr for distances of 120, 130, 140, and 150 pc, respectively (no plausible orbits were found assuming a distance of 160 pc). If confirmed as a young object member of AB Doradus, we estimate masses of 11 ± 1 M Jup and 9 ± 1 M Jup with both component masses below the Deuterium-burning mass limit. Gravity-sensitive indicators are more consistent with a field-age binary. While the young L6+T3 case is underluminous in a color–magnitude diagram at the AB Doradus kinematic distance, the young L7+T7.5 case could be viable. Its proper motion and radial velocity as a combined-light source yield a high membership probability for AB Doradus. Peculiarities in the near-infrared spectrum of this source suggest it to be a blended-light binary with L6.0 ± 1.0 and T3.0 ± 1.8 or L7.0 ± 0.6 and T7.5 ± 0.4 components. We present the identification of WISE J135501.90‑825838.9 as a spectral binary system with a slight possibility of planetary-mass components in the 130–200 Myr AB Doradus moving group.
An L+T Spectral Binary with Possible AB Doradus Kinematicsīardalez Gagliuffi, Daniella C.