First observed interaction of the circumstellar envelope of an S-star with the environment of Sgr A*

ATel #14306; Florian Peißker, Basel Ali, Michal Zajacek, Andreas Eckart, S. Elaheh Hosseini, Vladimir Karas, Yann Clenet, Nadeen B. Sabha, Lucas Labadie, Matthias Subroweit
on 7 Jan 2021; 08:51 UT
Credential Certification: Florian Peissker (peissker@ph1.uni-koeln.de)

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Here we report the dynamic interaction of a circumstellar envelope of an S-star with the environment of Sgr A* or the IRS16 complex. The L'-band observations were carried out with COMIC/ADONIS+RASOIR (1999) and NACO (2002-2018). Around S50, we observe a spherical dust envelope (1999) that interacts with a possible wind that is created at the position of Sgr A* or IRS16 (2002-2018). The dusty component of the system is known as X7 and to date, it was believed that the nature of the system can be described as a bow shock. Whereas the description of the X7/S50 system follows a Wilkinoide shape until 2009, we observe an increasingly prominent detachment of the system after 2009. Based on the L'-band size of X7, the Br\gamma emission line maps (observed with SINFONI), and the derived close 3d distance between S33 and S50, we speculate that an almost destructive event took place in 2009. The possible interaction of the two S-stars resulted in a detachment of the gaseous and dusty shell from its host star. Whereas a tidal disruption event, that would lead to increased flaring activity of the supermassive black hole (SMBH) Sgr A*, can not be excluded, we observe an overall stable shell throughout the years (besides the prominent elongation). In 2018, the position angle with respect to Sgr A* does not coincide with the position of the SMBH anymore. Hence, a wind that is created at the position of Sgr A* may not be the only origin of the dynamic interaction with X7/S50. We consider, that the IRS16 could be responsible. In this scenario, the S-cluster can be described as a (gravitational) lens. This would be consistent with the mini-cavity footprint. However, we encourage galactic center groups with access to L'-band observations to witness the dynamical evolution of the X7/S50 system. If the elongation of X7 does continue to increase, it should be soon as half of the size of the S-cluster. The related paper is accepted by ApJ, a preprint is available at https://arxiv.org/abs/2101.02077