Star Formation and Dynamics in the Galactic Centre

TL;DR

This paper reviews the complex processes of star formation and dynamical evolution near the supermassive black hole at the Galactic Centre, discussing various formation scenarios and their challenges.

Contribution

It provides a comprehensive review of existing theories on star formation and dynamics in the Galactic Centre, highlighting key challenges and recent developments.

Findings

Multiple formation scenarios are discussed, including in situ and migration models.

Challenges remain in explaining the formation of early-type stars near the SMBH.

The review identifies key issues to address for understanding star formation in extreme environments.

Abstract

The centre of our Galaxy is one of the most studied and yet enigmatic places in the Universe. At a distance of about 8 kpc from our Sun, the Galactic centre (GC) is the ideal environment to study the extreme processes that take place in the vicinity of a supermassive black hole (SMBH). Despite the hostile environment, several tens of early-type stars populate the central parsec of our Galaxy. A fraction of them lie in a thin ring with mild eccentricity and inner radius ~0.04 pc, while the S-stars, i.e. the ~30 stars closest to the SMBH (<0.04 pc), have randomly oriented and highly eccentric orbits. The formation of such early-type stars has been a puzzle for a long time: molecular clouds should be tidally disrupted by the SMBH before they can fragment into stars. We review the main scenarios proposed to explain the formation and the dynamical evolution of the early-type stars in the GC. In particular, we discuss the most popular in situ scenarios (accretion disc fragmentation and molecular cloud disruption) and migration scenarios (star cluster inspiral and Hills mechanism). We focus on the most pressing challenges that must be faced to shed light on the process of star formation in the vicinity of a SMBH.