Collision-induced mass loss and mass gain on an extremely massive star. An analytical approach and a static proto-globular cluster test-case

Abstract

The objective of this study is to analytically explore mass loss and gain induced by stellar collisions on a gas-accreting extremely massive star (aEMS, 10^3 <= M/M_sun <= 10^4). We also consider its contribution to the mass budget in the context of forming multiple stellar populations in a typical protoglobular cluster. We used MESA to build a series of aEMS models up to 2e4 M_sun for three [Fe/H] values, covering the metallicity range of Galactic GCs, with different treatments of super-adiabatic convection. We set analytical prescriptions to quantify collision-induced mass loss when a star spirals in and deposits energy into the envelope of the aEMS. We used a Monte Carlo approach to simulate the effects of multiple collisions on an aEMS of initial mass 10^3 M_sun in a static proto-GC, accounting for mass loss and gain from collisions, gas accretion, and stellar winds. We show that assumptions on super-adiabaticity in radiation-dominated layers significantly impact aEMS properties and their collision responses: extended stars tend to lose mass, while compact ones are more likely to gain it. Our MC simulations predict total mass lost and gained, along with timescales and contributions from winds and collisions. The results depend on both the aEMS structure and the gas accretion rate during the collision phase. Under certain conditions, the EMS shows a "conveyor belt" behavior, processing up to 10^5.5 M_sun of material in 5 Myr. This study provides theoretical predictions supporting aEMSs as contributors to the abundance anomalies observed in GCs. It emphasizes the need to include collision dynamics and mass transfer in aEMS formation and evolution models in dense stellar environments. We provide a grid of predictions for stellar M-R-[Fe/H]-structure relations and collision-induced mass loss and gain, suitable for hydro and N-body simulations.

References in corpus (40)

• Modules for Experiments in Stellar Astrophysics (MESA)
• Modules for Experiments in Stellar Astrophysics (MESA): Pulsating Variable Stars, Rotation, Convective Boundaries, and Energy Conservation
• The Hubble Space Telescope UV Legacy Survey of Galactic Globular Clusters. I. Overview of the Project and Detection of Multiple Stellar Populations
• Updated Electron-Conduction Opacities: The Impact on Low-Mass Stellar Models
• The Hubble Space Telescope UV Legacy Survey of Galactic Globular Clusters. IX. The Atlas of Multiple Stellar Populations
• How mergers magnetise massive stars
• What is a globular cluster? An observational perspective
• On the self-enrichment scenario of galactic globular clusters: Constraints on the IMF
• Population III star formation in a Lambda CDM universe, I: The effect of formation redshift and environment on protostellar accretion rate
• The evolution of runaway stellar collision products
• The evolution of rotating very massive stars with LMC composition
• The Evolution of Supermassive Population III Stars
• Looking outside the Galaxy: the discovery of chemical anomalies in 3 old Large Magellanic Cloud clusters
• The chemical composition of red giant stars in four intermediate-age clusters of the Large Magellanic Cloud
• The Hubble Space Telescope UV Legacy Survey of Galactic Globular Clusters. XIX. A Chemical Tagging of the Multiple Stellar Populations Over the Chromosome Maps
• Multiple populations in the old and massive Small Magellanic Cloud globular cluster NGC121
• New Conductive Opacities for White Dwarf Envelopes
• Star-planet interactions: II. Is planet engulfment the origin of fast rotating red giants?
• Long-term evolution of a magnetic massive merger product
• Photometry and astrometry with JWST -- I. NIRCam Point Spread Functions and the first JWST colour-magnitude diagrams of a globular cluster
• Convective envelopes in rotating OB stars
• NGC 6535: the lowest mass Milky Way globular cluster with a Na-O anti-correlation? Cluster mass and age in the multiple population context
• Revisiting nucleosynthesis in globular clusters: the case of NGC 2808 and the role of He and K
• Mixing in massive stellar mergers
• Multiple stellar populations and their evolution in globular clusters: A nucleosynthesis perspective
• Explaining the differences in massive star models from various simulations
• Physics and evolution of the most massive stars in 30 Dor. Mass loss, envelope inflation, and a variable upper stellar mass limit
• Birth of convective low-mass to high-mass second Larson cores
• Stellar models and isochrones from low-mass to massive stars including pre-main sequence phase with accretion
• Exploring the nature and synchronicity of early cluster formation in the Large Magellanic Cloud IV: Evidence for Multiple Populations in Hodge 11 and NGC 2210
• JWST uncovers helium and water abundance variations in the bulge globular cluster NGC 6440
• The Art of Modeling Stellar Mergers and the Case of the B[e] Supergiant R4 in the Small Magellanic Cloud
• Leveraging HST with MUSE: I. Sodium abundance variations within the 2 Gyr-old cluster NGC 1978
• The most massive Population III stars
• Chemistry of multiple stellar populations in the mono-metallic, in situ, bulge globular cluster NGC 6388
• Constraints on the multiplicity of the most massive stars known: R136 a1, a2, a3, and c
• Three Dimensional Natures of Massive Star Envelopes
• The Evolution of Accreting Population III Stars at 10${}^{-6}$-10${}^3$ M${}_{\odot }$/yr
• Leveraging HST with MUSE: II. Na-abundance variations in intermediate age star clusters
• Decoding the bifurcated red-giant branch as a tracer of multiple stellar populations in the young Large Magellanic Cloud cluster NGC 2173