Probing the formation of planetesimals in the Galactic Centre using Sgr A* flares

Abstract

Flares in X-ray and near infrared are observed above the quiescent emission of the supermassive black hole (SBH) in the Galactic Centre (GC) at a rate of approximately once per day. One proposed energy source for these flares is the tidal disruption of planetesimals with radius $\gtrsim 10$ km passing within $\sim$ 1 AU of the SBH. Very little is known about the formation and evolution of planetesimals in galactic nuclei such as the GC, making predictions for flaring event rates uncertain. We explore two scenarios for the formation of planetesimals in the GC: (1) in a large-scale cloud bound to the SBH, and (2) in debris discs around stars. We model their orbital evolution around the SBH using the Fokker-Planck equation and investigate the effect of gravitational interactions with various relevant perturbers. Our predicted flaring rate, $\approx 0.6\mathrm{da}{\mathrm{y}}^{-1}$, is nearly independent of the distribution of perturbers. Moreover, it is insensitive to scenarios (1) or (2). The assumed number of planetesimals per star is consistent with debris discs around stars in the Solar neighbourhood. In scenario (1) this implies that the number of planetesimals formed in the large-scale cloud is strongly correlated with the number of stars, and this requires finetuning for our results to be consistent with the observed flaring rate. We favour the alternative explanation that planetesimals in the GC are formed in debris discs around stars, similar to the Solar neighbourhood.

arXiv commentAccepted for publication in MNRAS. 21 pages, 12 figures

References in corpus (46)

• A Fundamental Relation Between Supermassive Black Holes and Their Host Galaxies
• Monitoring stellar orbits around the Massive Black Hole in the Galactic Center
• Comprehensive analytic formulae for stellar evolution as a function of mass and metallicity
• Measuring Distance and Properties of the Milky Way's Central Supermassive Black Hole with Stellar Orbits
• The Galactic Center Massive Black Hole and Nuclear Star Cluster
• Chandra X-ray Spectroscopic Imaging of Sgr A* and the Central Parsec of the Galaxy
• Near-infrared flares from accreting gas around the supermassive black hole at the Galactic Centre
• SINFONI in the Galactic Center: young stars and IR flares in the central light month
• Rapid X-ray flaring from the direction of the supermassive black hole at the Galactic Centre
• The Stellar Cusp Around the Supermassive Black Hole in the Galactic Center
• Resonant Relaxation in Stellar Systems
• A Disk of Young Stars at the Galactic Center as Determined by Individual Stellar Orbits
• Stellar Processes Near the Massive Black Hole in the Galactic Center
• Evidence for Warped Disks of Young Stars in the Galactic Center
• The nuclear star cluster of the Milky Way: proper motions and mass
• Massive perturber-driven interactions of stars with a massive black hole
• The structure of the nuclear stellar cluster of the Milky Way
• A size of ~1 AU for the radio source Sgr A* at the centre of the Milky Way
• Resonant relaxation near a massive black hole: the stellar distribution and gravitational wave sources
• Multi-physics simulations using a hierarchical interchangeable software interface
• The Astrophysical Multipurpose Software Environment
• XMM-Newton observation of the brightest X-ray flare detected so far from SgrA*
• Surface Brightness Profile of the Milky Way's Nuclear Star Cluster
• A Chandra/HETGS Census of X-ray Variability From Sgr A* During 2012
• Evolution of the Dark Matter Distribution at the Galactic Center
• The star formation history of the Milky Way's Nuclear Star Cluster
• The Distribution of Stars and Stellar Remnants at the Galactic Center
• Really Cool Stars and the Star Formation History at the Galactic Center
• Kinematics of the old stellar population at the Galactic Center
• Stellar Dynamics of Extreme-Mass-Ratio Inspirals
• The two states of Sgr A* in the near-infrared: bright episodic flares on top of low-level continuous variability
• Evidence for a Long-Standing Top-Heavy IMF in the Central Parsec of the Galaxy
• Dynamical evolution of the young stars in the Galactic center: N-body simulations of the S-stars
• Sgr A* flares: tidal disruption of asteroids and planets?
• NuSTAR detection of high-energy X-ray emission and rapid variability from Sagittarius A* flares
• 3D stellar kinematics at the Galactic center: measuring the nuclear star cluster spatial density profile, black hole mass, and distance
• Collisionally Regenerated Dark Matter Structures in Galactic Nuclei
• The efficiency of resonant relaxation around a massive black hole
• The Millennium Galaxy Catalogue: The $M_{bh}$--$L_{spheroid}$ derived supermassive black hole mass function
• Dynamical and evolutionary constraints on the nature and origin of hypervelocity stars
• Resonant relaxation near a massive black hole: the dependence on eccentricity
• Tidal disruption of a super-Jupiter by a massive black hole
• Relativity and the evolution of the Galactic center S-star orbits
• Constraining the dark cusp in the Galactic Center by long-period binaries
• Stripping a debris disk by close stellar encounters in an open stellar cluster
• Are SMBHs shrouded by "super-Oort" clouds of comets and asteroids?

Cited by in corpus (3)

• The origin of interstellar asteroidal objects like 1I/2017 U1 'Oumuamua
• Formation and evolution of nuclear star clusters with in-situ star-formation: Nuclear cores and age segregation
• Relaxation near supermassive black holes driven by nuclear spiral arms: anisotropic hypervelocity stars, S-stars and tidal disruption events