The discrepancy between dynamical and theoretical masses for low-mass multiple systems

Multiple systems prove to be excellent benchmarks for testing evolutionary models. By monitoring the motions of the components in the system we can derive orbital solutions that yield robust dynamical masses to test the theory against. However, the models and the dynamical masses are not alway in agreement, which is especially apparent for low-mass systems. Because not many multiple systems in the low-mass regime with short enough periods to obtain orbital solutions in reasonable time-frames have been observed, systems with constrained orbits become important calibrators for the models. In this talk I will present results from the AstraLux multiple system monitoring program, explaining how we can take advantage of the Lucky Imaging technique to observe otherwise unresolved systems to find faint companions, which have short enough orbits that orbital fits start to provide constrained results. I will in detail discuss the triplet-system 2MASS J10364483+1521394, which shows a 30 percent higher dynamical mass for the individual components compared to mass-values obtained from theoretical models.

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