Dust-enshrouded star near supermassive black hole: predictions for high-eccentricity passages near low-luminosity galactic nuclei

Abstract

Supermassive black holes reside in cores of galaxies, where they are often surrounded by a nuclear cluster and a clumpy torus of gas and dust. Mutual interactions can set some stars on a plunging trajectory towards the black hole. We model the pericentre passage of a dust-enshrouded star during which the dusty envelope becomes stretched by tidal forces and is affected by the interaction with the surrounding medium. In particular, we explore under which conditions these encounters can lead to periods of enhanced accretion activity. We discuss different scenarios for such a dusty source. To this end, we employed a modification of the Swift integration package. Elements of the cloud were modelled as numerical particles that represent the dust component that interacts with the optically thin gaseous environment. We determine the fraction of the total mass of the dust component that is diverted from the original path during the passages through the pericentre at $\sim 10^3$ Schwarzschild radii and find that the main part of the dust ($\gtrsim 90\%$ of its mass) is significantly affected upon the first crossing. The fraction of mass captured at the second passage generally decreases to very low values. As an example, we show predictions for the dusty source evolution assuming the current orbital parameters of the G2 cloud (also known as Dusty S-Cluster Object, DSO) in our Galactic centre. Encounter of a core-less cloud with a supermassive black hole is, most likely, a non-repeating event: the cloud is destroyed. However, in the case of a dust-enshrouded star, part of the envelope survives the pericentre passage. We discuss an offset of $\lesssim 0.3$ arcsec between the centre of mass of the diverted part and the star along the eccentric orbit. Finally, we examine an interesting possibility of a binary star embedded within a common wind envelope that becomes dispersed at the pericentre passage.

18 pages, 15 figures, Astronomy and Astrophysics accepted

References in corpus (5)

• Advection-Dominated Accretion and the Black Hole Event Horizon
• The Submillimeter Bump in Sgr A* from Relativistic MHD Simulations
• Computing the dust distribution in the bowshock of a fast moving, evolved star
• Origin of the S Stars in the Galactic Center
• On highly eccentric stellar trajectories interacting with a self-gravitating disc in Sgr A*

Cited by in corpus (21)

• Detection of Galactic Center source G2 at 3.8 $\mu$m during periapse passage
• Stellar transits across a magnetized accretion torus as a mechanism for plasmoid ejection
• S62 and S4711: Indications of a population of faint fast moving stars inside the S2 orbit -- S4711 on a 7.6 year orbit around Sgr~A*
• Monitoring the Dusty S-Cluster Object (DSO/G2) on its Orbit towards the Galactic Center Black Hole
• Standardizing reverberation-measured C IV time-lag quasars, and using them with standardized Mg II quasars to constrain cosmological parameters
• Monitoring dusty sources in the vicinity of Sgr A*
• Polarized near-infrared light of the Dusty S-cluster Object (DSO/G2) at the Galactic Center
• A Stellar Wind Origin for the G2 Cloud: Three-Dimensional Numerical Simulations
• Alive but Barely Kicking: News from 3+ years of Swift and XMM-Newton X-ray Monitoring of Quasi-Periodic Eruptions from eRO-QPE1
• Near- and mid-infrared observations in the inner tenth of a parsec of the Galactic center -- Detection of proper motion of a filament very close to Sgr~A*
• No asymmetric outflows from Sagittarius A* during the pericenter passage of the gas cloud G2
• A new bow-shock source with bipolar morphology in the vicinity of Sgr A*
• A binary system in the S cluster close to the supermassive black hole Sagittarius A*
• Effect of extinction on quasar luminosity distances determined from UV and X-ray flux measurements
• The apparent tail of the Galactic center object G2/DSO
• First observed interaction of the circumstellar envelope of an S-star with the environment of Sgr A*
• Dusty plasma in active galactic nuclei
• No Microwave Flare of Sagittarius A* around the G2 Periastron Passing
• Candidate Young Stellar Objects in the S-cluster: The Kinematic Analysis of a Sub-population of the Low-mass G-objects close to Sgr A*
• Closing the gap: Follow-up observations of peculiar dusty objects close to Sgr A* using ERIS
• Dips in the sub-TeV gamma-ray light curves from central parts of galaxies due to transiting luminous stars