2023/06/03 by Andreas Burkert, S. Gillessen, Burkert, Andreas +11 · 4 citations
Physics and Astronomy · Engineering · #Astrophysical Phenomena and Observations #Experimental and Theoretical Physics Studies #Mechanical Engineering and Vibrations Research
paper · pdf · doi:10.48550/arxiv.2306.02076
The orbital distribution of the S-star cluster surrounding the supermassive black hole in the center of the Milky Way is analyzed. A tight, roughly exponential dependence of the pericenter distance rp on orbital eccentricity e⋆ is found, log (rp)∼(1-e⋆), which cannot be explained simply by a random distribution of semi-major axes and eccentricities. No stars are found in the region with high e⋆ and large log rp or in the region with low e⋆ and small log rp. G-clouds follow the same correlation. The likelihood P(log rp,(1-e⋆)) to determine the orbital parameters of S-stars is determined. P is very small for stars with large e⋆ and large log rp. S-stars might exist in this region. To determine their orbital parameters, one however needs observations over a longer time period. On the other hand, if stars would exist in the region of low log rp and small e⋆, their orbital parameters should by now have been determined. That this region is unpopulated therefore indicates that no S-stars exist with these orbital characteristics, providing constraints for their formation. We call this region, defined by log (rp/AU) < 1.57+2.6(1-e⋆), the zone of avoidance. Finally, it is shown that the observed frequency of eccentricities and pericenter distances is consistent with a random sampling of log rp and e⋆. However, only if one takes into account that no stars exist in the zone of avoidance and that orbital parameters cannot yet be determined for stars with large rp and large e⋆.