On the Missing Red Giants near the Galactic Center

Abstract

There is a long-acknowledged deficiency of bright red giants relative to fainter old stars within a few arc seconds of Sgr A*. We explore whether this could be due to tidal stripping by the central black hole. This requires putting the stars onto highly eccentric orbits, for which we evaluate diffusion by both scalar resonant and non-resonant relaxation of the orbital angular momentum. We conclude that tidal stripping does not discriminate sufficiently between main-sequence and red giant stars. While the tidal loss cone increases with stellar radius, the rate of diffusion into the loss cone increases only logarithmically, whereas the lifetime on the red giant branch decreases more rapidly than $R_{\ast }^{-1}$. In agreement with previous studies, we find that stellar collisions are a more likely explanation for the deficiency of bright red giants relative to fainter ones.

11 pages, 5 figures, 2 tables

References in corpus (34)

• The Galactic Center Massive Black Hole and Nuclear Star Cluster
• The First Measurement of Spectral Lines in a Short-Period Star Bound to the Galaxy's Central Black Hole: A Paradox of Youth
• The Two Young Star Disks in the Central Parsec of the Galaxy: Properties, Dynamics and Formation
• Detection of the Schwarzschild precession in the orbit of the star S2 near the Galactic centre massive black hole
• The Absolute Magnitude of the Sun in Several Filters
• Resonant Relaxation in Stellar Systems
• The mass distribution in the Galactic Centre from interferometric astrometry of multiple stellar orbits
• Evidence for Warped Disks of Young Stars in the Galactic Center
• The nuclear star cluster of the Milky Way: proper motions and mass
• The structure of the nuclear stellar cluster of the Milky Way
• Strong mass segregation around a massive black hole
• Red Giant Branch stars: the theoretical framework
• Properties of the Remnant Clockwise Disk of Young Stars in the Galactic Center
• High angular resolution integral-field spectroscopy of the Galaxy's nuclear cluster: a missing stellar cusp?
• The Distribution of Stars and Stellar Remnants at the Galactic Center
• The distribution of stars near the super-massive black hole in the Galactic Center
• Stellar Populations in the Central 0.5 pc of the Galaxy I: A New Method for Constructing Luminosity Functions and Surface-Density Profiles
• The Milky Way's nuclear star cluster: Old, metal-rich, and cuspy
• The distribution of old stars around the Milky Way's central black hole I: Star counts
• Steady state relativistic stellar dynamics around a massive black hole
• The Nuclear Cluster of the Milky Way: Total Mass and Luminosity (long version)
• Red giant collisions in the galactic centre
• The stars of the galactic center
• Scalar Resonant Relaxation of Stars Around a Massive Black Hole
• On Socially Distant Neighbors: Using Binaries to Constrain the Density of Objects in the Galactic Center
• The statistical mechanics of relativistic orbits around a massive black hole
• Depletion of bright red giants in the Galactic center during its active phases
• Mapping the Galactic centre's dark cluster via Resonant Relaxation
• An order-disorder phase transition in black-hole star clusters
• Making Bright Giants Invisible At The Galactic Centre
• Order-disorder phase transition in black-hole star clusters -- III. A mono-energetic cluster
• Order-disorder phase transition in black-hole star clusters. II. A scale-free cluster
• Photometric Classification of Stars Around the Milky Way's Central Black Hole: I. Central Parsec
• Red giant - jet collisions in galactic nuclei I: 3D hydrodynamical model of a few stellar orbits