Very Massive Stars and Pair-Instability Supernovae: Mass-loss Framework for low Metallicity

Abstract

Very massive stars (VMS) up to 200-300 $M_{\odot }$ have been found in the Local Universe. If they would lose little mass they produce intermediate-mass black holes or pair-instability supernovae (PISNe). Until now, VMS modellers have extrapolated mass-loss vs. metallicity ($Z$) exponents from optically-thin winds, resulting in a range of PISN thresholds that might be unrealistically high in $Z$, as VMS develop optically-thick winds. We utilize the transition mass-loss rate of Vink and Gräfener (2012) that accurately predicts mass-loss rates of Of/WNh ("slash") stars that characterize the morphological transition from absorption-dominated O-type spectra to emission-dominated WNh spectra. We develop a wind efficiency framework, where optically thin winds transition to enhanced winds, enabling us to study VMS evolution at high redshift where individual stars cannot be resolved. We present a MESA grid covering $Z_{\odot }/2$ to $Z_{\odot }/100$. VMS above the transition evolve towards lower luminosity, skipping the cool supergiant phase but directly forming pure He stars at the end of hydrogen burning. Below the transition, VMS evolve as cooler luminous blue variables (LBVs) or yellow hypergiants (YHGs), naturally approaching the Eddington limit. Strong winds in this YHG/LBV regime -- combined with a degeneracy in luminosity -- result in a mass-loss runaway where a decrease in mass increases wind mass loss. Our models indicate an order-of-magnitude lower threshold than usually assumed, at $Z_{\odot }/20$ due to our mass-loss runaway. While future work on LBV mass loss could affect the PISN threshold, our framework will be critical for establishing definitive answers on the PISN threshold and galactic chemical evolution modelling.

Accepted for publication in MNRAS, 18 pages, 8 figures, 2 appendix

References in corpus (34)

• Modules for Experiments in Stellar Astrophysics (MESA)
• Modules for Experiments in Stellar Astrophysics (MESA): Pulsating Variable Stars, Rotation, Convective Boundaries, and Energy Conservation
• Pulsational Pair-Instability Supernovae
• Pulsational pair instability as an explanation for the most luminous supernovae
• The R136 star cluster hosts several stars whose individual masses greatly exceed the accepted 150 Msun stellar mass limit
• Mind the gap: The location of the lower edge of the pair instability supernovae black hole mass gap
• Very massive stars, pair-instability supernovae and intermediate-mass black holes with the SEVN code
• The empirical metallicity dependence of the mass-loss rate of O- and early B-type stars
• Mass loss from late-type WN stars and its Z-dependence: very massive stars approaching the Eddington limit
• The most massive stars in the Arches cluster
• The evolution of rotating very massive stars with LMC composition
• Pair creation supernovae at low and high redshift
• The VLT-FLAMES Tarantula Survey XVII. Physical and wind properties of massive stars at the top of the main sequence
• On the consistent treatment of the quasi-hydrostatic layers in hot star atmospheres
• On the evolution and fate of supermassive stars
• Metallicity-dependent wind parameter predictions for OB stars
• A consistent solution for the velocity field and mass-loss rate of massive stars
• Properties of WNh stars in the Small Magellanic Cloud: evidence for homogeneous evolution
• Rotating massive O stars with non-spherical 2D winds
• The Deaths of Very Massive Stars
• Wind-envelope interaction as the origin of the slow cyclic brightness variations of luminous blue variables
• On the optically-thick winds of Wolf-Rayet stars
• The temperature dependency of Wolf-Rayet-type mass loss: An exploratory study for winds launched by the hot iron bump
• Numerical simulations of continuum-driven winds of super-Eddington stars
• Resolving the core of R136 in the optical
• New mass-loss rates of B supergiants from global wind models
• A Study of Primordial Very Massive Star Evolution
• SNAPSHOT: Connections between Internal and Surface Properties of Massive Stars
• Evolution of massive stars with new hydrodynamic wind models
• Reverse Algols and hydrogen-rich Wolf-Rayet stars from very massive binaries
• Empirical properties of Very Massive Stars
• Exploring the influence of different velocity fields on Wolf-Rayet star spectra
• SN 1961V: A Pulsational Pair-Instability Supernova
• iPTF14hls in the circumstellar medium interaction model: A promising candidate for a pulsational pair-instability supernova

Cited by in corpus (22)

• Very massive stars and Nitrogen emitting galaxies
• Impact of gas hardening on the population properties of hierarchical black hole mergers in AGN disks
• Observable and ionizing properties of star-forming galaxies with very massive stars and different IMFs
• Very Massive Star Models: I. Impact of Rotation and Metallicity and Comparisons with Observations
• The landscape of binary core-collapse supernova progenitors and the late emergence of Wolf-Rayet winds
• Improving 1D stellar atmosphere models with insights from multi-dimensional simulations I. 1D vs 2D stratifications and spectral comparison for O stars
• Mergers all the way down: stellar collisions and kinematics of a dense hierarchically forming massive star cluster in a dwarf starburst
• Development of convective envelopes in massive stars: Implications for gravitational wave sources
• The initial mass-remnant mass relation for core collapse supernovae
• Very massive stars at low metallicity: evolution, synthetic spectroscopy, and impact on the integrated light of starbursts
• Impact of accretion-induced chemically homogeneous evolution on stellar and compact binary populations
• Metal-poor single Wolf-Rayet stars: The interplay of optically thick winds and rotation
• The impact of wind mass loss on nucleosynthesis and yields of very massive stars at low metallicity
• Evolutionary models for the Very Massive Stars in the R136 cluster of 30 Doradus in the Large Magellanic Cloud
• MARTA: The connection between chemical enrichment, feedback, and dust in a Wolf-Rayet galaxy at z$\sim$2
• Near-Eddington mass loss of hydrogen-rich Wolf-Rayet stars
• Dynamically consistent analysis of Galactic WN4b stars
• Cosmic wallflowers: the circumgalactic origins of isolated ultra-compact star clusters at $z>7$
• Evolution of stars with 60 and 200 Msun: predictions for WNh stars in the Milky Way
• The wind properties of O-type stars at sub-SMC metallicity
• FROST-CLUSTERS -- III. Metallicity-dependent intermediate mass black hole formation by runaway collisions in dense star clusters
• Evolution of Massive Main-sequence Stars in Rapid Population Synthesis. I. Framework and Implementation