REVIEW
Mass-loss predictions for O and B stars as a function of metallicity
Astrophysics · Submitted 29 Jan 2001 · 47 references
Pith's verdict: A solid, widely used mass-loss recipe, but its single Z^0.85 term is an average that hides real per-temperature spread in the B-supergiant regime.
T0 · AI review
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Referee report
The paper
The paper claims
Mass loss from massive O and B stars follows a single power law in metal abundance over roughly 1/30 to 3 times solar metallicity.
The reading
What carries the argument
The load-bearing machinery is the Unified Monte Carlo wind model: a model atmosphere with non-LTE level populations supplies the density and temperature structure, then photon packets are followed through about 50-60 shells and more than $10^5$ spectral lines of H through Zn, with multiple scatterings counted, until the radiative momentum transferred matches the wind momentum. This avoids the core-halo split of classical line-driving treatments and lets the authors compute a self-consistent $Ṁ$ for each grid point. The metallicity dependence is extracted as the slope of $log Ṁ$ versus $log(Z/Z_⊙)$ at fixed temperature and wind-speed ratio, and the bi-stability jumps are handled by fitting the characteristic wind density at the jump and converting it to a jump temperature.
Extended reading notes
Core claim
The central claim is that, over $1/30 ≤ Z/Z_⊙ ≤ 3$, the mass-loss rate of massive stars obeys a single power law in metal abundance when the terminal wind speed is held fixed: $Ṁ ∝ Z^{0.85} v_∞^p$, with $p=-1.23$ for stars hotter than about $25{,}000$ K and $p=-1.60$ for B supergiants cooler than that. Feeding in the cited scaling $v_∞ ∝ Z^{0.13}$ turns this into an overall dependence $Ṁ ∝ Z^{0.69}$ for the hot stars and $Ṁ ∝ Z^{0.64}$ for the B supergiants. The exponent is reported as constant across that range, which is what licenses adding a single $+0.85 log(Z/Z_⊙)$ term to the earlier Vink et al. (2000) recipe on both sides of the $25{,}000$ K bi-stability jump. The authors also locate additional jumps caused by iron and carbon recombination and give formulae for their temperatures as functions of wind density.
Load-bearing premise
The load-bearing premise is that the exponent calibrated at $T_{eff}=50{,}000$ K and $v_∞/v_{esc}=2.0$, $m=0.85±0.10$, transfers unchanged to every other temperature and wind-speed ratio, with bi-stability jumps assumed to cancel on average; the paper itself notes that a pure power law may fail at the extremes and that the LMC abundance is uncertain, but the temperature-by-temperature constancy is asserted rather than tabulated.
Editorial extensions
If this is right
- At $Z/Z_⊙=1/30$, the new exponent predicts an O-star mass-loss rate roughly a factor of ten below solar, where the old square-root rule would give only about a factor of five.
- Evolutionary calculations that adopt the recipe should retain more envelope mass in low-metallicity massive stars and therefore end with different pre-supernova structures than calculations using $m=1/2$.
- Population synthesis must include the bi-stability jumps at about $25{,}000$ K, $15{,}000$ K, and $35{,}000$ K; the recipe gives each jump temperature from the characteristic wind density.
- At low metallicity, where CNO rather than iron dominates the line acceleration near the sonic point, oxygen-based abundance estimates are the appropriate input, and iron-based estimates need the conversion given in Table 5.
- The publicly available routine lets other workers test the recipe against new low-metallicity observations.
Reading between the lines
- A natural next test is to run the recipe inside a stellar-evolution code and see whether the lower low-$Z$ mass loss changes the predicted maximum black-hole mass or the stripped-envelope supernova fraction.
- The $0.85$ exponent is close to the classical force-multiplier estimate $m=(1-α)/(α-δ) ≈ 0.8$; if multiple scattering mainly changes the normalization, the residual scatter in the fits should correlate with iron abundance rather than total $Z$.
- The LMC comparison improves when one adopts $Z=0.8Z_⊙$ from a single O star; individual stellar abundances for the LMC and SMC samples would turn that post-hoc choice into a real test.
- Because the carbon jump at $35{,}000$ K appears only at low $Z$ and low wind density, a targeted survey of hot, low-$Z$ dwarfs could look for the terminal-velocity change that the paper leaves open.
Original abstract
We have calculated a grid of massive star wind models and mass-loss rates for a wide range of metal abundances between 1/100 and 10 Z/Zsun. The calculation of this grid completes the Vink et al. (2000) mass-loss recipe with an additional parameter Z. We have found that the exponent of the power law dependence of mass loss vs. metallicity is constant in the range between 1/30 and 3 Z/Zsun. The mass-loss rate scales as Mdot \propto Z^0.85 Vinf^p with p = -1.23 for stars with Teff \ga 25000 K, and p = -1.60 for the B supergiants with Teff \la 25000 K. Taking also into account the metallicity dependence of Vinf, using the power law dependence Vinf \propto Z^0.13 from Leitherer et al. (1992), the overall result of mass loss as a function of metallicity can be represented by Mdot \propto Z^0.69 for stars with Teff \ga 25000 K, and Mdot \propto Z^0.64 for B supergiants with Teff \la 25000 K. Our mass-loss predictions are successful in explaining the observed mass-loss rates for Galactic and Small Magellanic Cloud O-type stars, as well as in predicting the observed Galactic bi-stability jump. Hence, we believe that our predictions are reliable and suggest that our mass-loss recipe be used in future evolutionary calculations of massive stars at different metal abundance. A computer routine to calculate mass loss is publicly available.
The compiled record
The paper's own sentences, arranged, kept beside the review and separate from it. Each label is drawn from a closed vocabulary; the number beside it is the probability the classifier gave that label. Numbers in the tables are the authors', checked by code. No sentence in this record was written by a model.
The abstract, sentence by sentence
We have calculated a grid of massive star wind models and mass-loss rates for a wide range of metal abundances between 1/100 and 10 Z/Zsun. The calculation of this grid completes the Vink et al. (2000) mass-loss recipe with an additional parameter Z. We have found that the exponent of the power law dependence of mass loss vs. metallicity is constant in the range between 1/30 and 3 Z/Zsun. The mass-loss rate scales as Mdot \propto Z^0.85 Vinf^p with p = -1.23 for stars with Teff \ga 25000 K, and p = -1.60 for the B supergiants with Teff \la 25000 K. Taking also into account the metallicity dependence of Vinf, using the power law dependence Vinf \propto Z^0.13 from Leitherer et al. (1992), the overall result of mass loss as a function of metallicity can be represented by Mdot \propto Z^0.69 for stars with Teff \ga 25000 K, and Mdot \propto Z^0.64 for B supergiants with Teff \la 25000 K. Our mass-loss predictions are successful in explaining the observed mass-loss rates for Galactic and Small Magellanic Cloud O-type stars, as well as in predicting the observed Galactic bi-stability jump. Hence, we believe that our predictions are reliable and suggest that our mass-loss recipe be used in future evolutionary calculations of massive stars at different metal abundance. A computer routine to calculate mass loss is publicly available.
background contribution method result interpretation main claim
| # | sentence | role | the authors' own work | states the main conclusion | strength |
|---|---|---|---|---|---|
| s0 | We have calculated a grid of massive star wind models and mass-loss rates for a wide range of metal abundances between 1/100 and 10 Z/Zsun. | contribution 0.72 | 0.97 | 0.05 | asserted 1.00 |
| s1 | The calculation of this grid completes the Vink et al. (2000) mass-loss recipe with an additional parameter Z. | contribution 0.76 | 0.74 | 0.08 | asserted 1.00 |
| s2 | We have found that the exponent of the power law dependence of mass loss vs. metallicity is constant in the range between 1/30 and 3 Z/Zsun. | result 1.00 | 0.96 | 0.19 | asserted 1.00 |
| s3 | The mass-loss rate scales as Mdot \propto Z^0.85 Vinf^p with p = -1.23 for stars with Teff \ga 25000 K, and p = -1.60 for the B supergiants with Teff \la 25000 K. | result 1.00 | 0.91 | 0.18 | asserted 1.00 |
| s4 | Taking also into account the metallicity dependence of Vinf, using the power law dependence Vinf \propto Z^0.13 from Leitherer et al. (1992), the overall result of mass loss as a function of metallicity can be represented by Mdot \propto Z^0.69 for stars with Teff \ga 25000 K, and Mdot \propto Z^0.64 for B supergiants with Teff \la 25000 K. | result 1.00 | 0.66 | 0.37 | asserted 0.99 |
| s5 | Our mass-loss predictions are successful in explaining the observed mass-loss rates for Galactic and Small Magellanic Cloud O-type stars, as well as in predicting the observed Galactic bi-stability jump. | result 0.84 | 0.83 | 0.32 | asserted 1.00 |
| s6 | Hence, we believe that our predictions are reliable and suggest that our mass-loss recipe be used in future evolutionary calculations of massive stars at different metal abundance. | interpretation 0.52 | 0.35 | 0.55 | hedged possibility 0.81 |
| s7 | A computer routine to calculate mass loss is publicly available. | contribution 0.81 | 0.57 | 0.03 | asserted 1.00 |
What was examined, and what was not
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Figures
Figures reproduced from arXiv:astro-ph/0101509 by the authors.
References
How later papers used it
481 later papers cite it
16 later papers by other authors are listed below: 15 used its method or tool and 1 used its data or values. 2 more papers by the same authors are listed: 1 used its method or tool and 1 compared its own results with it.
Uses its method or tool 16 of 225 papers with this label · 1 by the same authors
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Included stellar winds from both components following this paper's prescription.
The eclipsing binary systems with $\delta$ Scuti component -- II. AB Cas (2022) · 1.00 · paraphrased: the licence does not allow quoting
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Used this paper's prescription for the core hydrogen burning phase.
Massive black holes regulated by luminous blue variable mass loss and magnetic fields (2019) · 1.00 · paraphrased: the licence does not allow quoting
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Wind driven mass loss follows the prescriptions of [ref] for stars with $>10^4K$ and surface hydrogen mass fraction $X_H>0.4$, [ref] for $>10^4K$ and surface $X_H<0.4$, and [ref] at all other times, with wind-scaling factors of 1.0.
The cosmic carbon footprint of massive stars stripped in binary systems (2021) · Pre-supernova evolution · 1.00
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For the mass loss in our models, we adopt the so-called “Dutch" scheme, employing the Vink et al. [ref] prescription for hot phases and the de Jager, Nieuwenhuijzen, and van der Hucht [ref] prescription for cool phases.
The Effect of Mass Loss and Convective Overshooting on the Pre-Collapse Structure, Composition, and Neutrino Emission of Red Supergiants (2026) · Modeling Red Supergiants with · 1.00
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Followed this paper for the winds.
Close Encounters of Wide Binaries Induced by the Galactic Tide: Implications for Stellar Mergers and Gravitational-Wave Sources (2024) · 1.00 · paraphrased: the licence does not allow quoting
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Computed mass loss rates for hydrogen-rich models following this paper, using a metallicity scaling of (Z/Zsun)^0.85.
Related progenitor models for long-duration gamma ray bursts and Type Ic superluminous supernovae (2018) · 1.00 · paraphrased: the licence does not allow quoting
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Employed a prescription combining the models of this paper for effective temperatures above 4000 K.
A Model for Eruptive Mass Loss in Massive Stars (2024) · 1.00 · paraphrased: the licence does not allow quoting
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Evolved stars to black holes using a package that includes updated prescriptions for stellar winds and mass loss from this paper.
Reconstructing the Genealogy of LIGO-Virgo Black Holes (2024) · 1.00 · paraphrased: the licence does not allow quoting
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Stellar winds are included using the algorithms from [ref] with an efficiency factor of 1.
The Stellar Merger Scenario for Black Holes in the Pair-instability Gap (2020) · setup · 1.00
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For each progenitor star with zero-age main-sequence (ZAMS) mass $M_⋆$ at $t=2.2$ Myr, we apply metallicity-dependent wind mass loss using the [ref] prescription over the remaining main-sequence lifetime ($∼1 - 2$ Myr for $M_⋆≳250$), obtaining a pre-collapse mass $M_pre$.
Repopulating the pair-instability mass gap without sustained growth to massive IMBHs: the case of 47\,Tuc (2026) · Seed Models · 1.00
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Adopted the Dutch wind model, which combines the models of this paper and another work.
Metallicity Ceiling in Quasars from Recycled Stellar Winds (2022) · 1.00 · paraphrased: the licence does not allow quoting
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Both sets rely on the wind mass-loss recipe of [ref] .
A model of anisotropic winds from rotating stars for evolutionary calculations (2023) · Numerical method · 1.00
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Adopted this paper's metallicity-dependent stellar wind prescriptions to determine the final stellar mass at core collapse.
Populating the upper black hole mass gap through stellar collisions in young star clusters (2020) · 1.00 · paraphrased: the licence does not allow quoting
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Followed this paper's theoretical prescription for wind mass loss during hot phases with surface hydrogen mass fraction at least 0.4.
How much hydrogen is in Type Ib and IIb supernova progenitors? (2021) · 1.00 · paraphrased: the licence does not allow quoting
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This configuration applies [ref] for thin and low-$Γ_e$ thick winds (see more in Section [ref]).
The Stellar Winds Atlas I: Current uncertainties in mass-loss rates (2026) · Wind Scheme Implementations · 1.00
By the same authors
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Hot O stars ($T_eff>10$kK) with surface hydrogen mass fraction $X_s>0.4$ use the metallicity-dependent mass loss recipe from [ref] .
Superadiabaticity and the metallicity independence of the Humphreys-Davidson limit (2021) (same authors) · Mass loss · 1.00
Uses its data or values 1 of 27 papers with this label
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Used equation (21) of this paper, which suggests the mass loss rate scales with metallicity as Z^0.85.
Effect of mass loss due to stellar winds on the formation of supermassive black hole seeds in dense nuclear star clusters (2021) · 0.80 · paraphrased: the licence does not allow quoting
Compares with it 1 of 30 papers with this label · 1 by the same authors
By the same authors
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For example, in Fig. [ref], we notice that while both the [ref] rates and our hydrodynamical predictions agree at the Arches transition, the two prescriptions exhibit very different behaviour above and below the transition.
Hydrodynamical mass-loss rates for Very Massive Stars II. New theoretical mass-loss predictions at solar metallicity (Z = 0.02) (2026) (same authors) · Comparison to other recipes · 1.00
How the literature uses it
69 arXiv papers cite this in 155 sentences
Papers citing it · 69 sentences without a confident label
Contests it 6 papers
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Again these comparisons and simple averages show quite clearly that the sudden increase in mass-loss rate predicted at the supposed bi-stability jump by the [ref] prescription is not present in these observational results.
X-Shooting ULLYSES: Massive Stars at low metallicity IX: Empirical constraints on mass-loss rates and clumping parameters for OB supergiants in the Large Magellanic Cloud · Is there a generic mass loss jump in the range $T_eff ∼15 - 35$ kK? · contest 0.91
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All research groups come to the conclusion that the [ref] prescription should be used cautiously, as it may overestimate the mass loss by up to a factor of 10–100 for stars cooler than 25 kK, agreeing more closely with the trends predicted by [ref] .
X-Shooting ULLYSES: Massive stars at low metallicity XV. On the metallicity dependence of B-supergiant mass-loss rates · Introduction · contest 0.75
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Consequently, population synthesis codes adopting [ref] , [ref] , or [ref] likely overestimate mass-loss rates in the optically thin winds regime, accelerating the depletion of hydrogen (H)-rich envelopes and leading to premature formation of WR stars.
The Stellar Winds Atlas I: Current uncertainties in mass-loss rates · Mass-loss rates · contest 0.85
Uses its method or tool 27 papers
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* Optically thin winds: For $logg≥3.0$ we use [ref] , hereafter GM23, while for $logg<3.0$ we adopt [ref] , hereafter V01.
The Stellar Winds Atlas II: Black Hole Formation at Solar Metallicity · Free-Electron Scattering transition (FESc) Models · 0.99
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The initial mass function is evolved through the single stellar evolution code $SSE$ by [ref] , with updated wind mass loss prescription [ref] , (pulsational) pair instability or (P)PISN recipe [ref] and supernova kick Maxwellian distribution (with $σ=265km/s$) from [ref] ; scaled by fallback mass for BHs [ref] .
Repopulating the pair-instability mass gap without sustained growth to massive IMBHs: the case of 47\,Tuc · Methods · 1.00
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We parameterise the wind terminal speed as a temperature dependent multiple of the escape speed, [equation] The escape speed is [equation] To mimic the usual bi-stability behaviour we adopt a two-branch scaling [ref] , [equation] We take $η_hot=2.6$, $η_cool=1.3$, and $T_bist=2.1×10^4 K$.
Habitable Zones Around Massive Stars: From the Main Sequence to Supergiants · Stellar evolution tracks · 0.92
Uses its data or values 4 papers
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The mass-loss prescription relevant for our work uses the mass-loss rate of [ref] during the main sequence phase, that of [ref] for the RSG phase, and those of [ref] and [ref] for the WR phase.
Multi-Dimensional MHD simulations of young Core-Collapse Supernova Remnants · Stellar model · 0.91
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We adopt $f_DC = 0.6$ for $Z = 0.003$ and $f_DC = 0.45$ for $Z = 0.007$, reflecting the stronger wind mass loss at higher metallicity [ref] .
Repopulating the pair-instability mass gap without sustained growth to massive IMBHs: the case of 47\,Tuc · Seed Models · 0.94
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Furthermore, [ref] found that the metallicity exponent ($α$) of the mass loss rate is constant in a wide range of metallicities $1/30 ≤Z/≤3$, with $= 0.019$ [ref] .
Stellar Black Holes and Compact Stellar Remnants · Mass loss through stellar winds · 0.92
Compares with it 10 papers
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In the context of the present study, the main difference in the predictions of these schemes is that [ref] predict significantly higher mass-loss rates for stars below $T_eff ∼22-25$ kK than for hotter stars, whereas [ref] do not predict such a jump but instead a steady decrease of mass-loss rates with decreasing temperature.
X-Shooting ULLYSES: Massive Stars at low metallicity IX: Empirical constraints on mass-loss rates and clumping parameters for OB supergiants in the Large Magellanic Cloud · Is there a generic mass loss jump in the range $T_eff ∼15 - 35$ kK? · 0.93
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We show that different but widely used models for extremely massive star wind rates ( [ref] versus [ref] ) result in final IMBH masses differing by a factor of $∼4$.
FROST-CLUSTERS -- III. Metallicity-dependent intermediate mass black hole formation by runaway collisions in dense star clusters · Summary and conclusions · 0.81
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We show that the mass-loss rates from [ref] , despite representing the weaker optically thin wind regime, predict similar mass-loss rates to [ref] and [ref] at $logL ≳6.3$, and higher than [ref] for $logL ≲6.05$.
The Stellar Winds Atlas I: Current uncertainties in mass-loss rates · Mass-loss rates · 0.99
Cites it as support 1 paper
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At the metallicities of interest for this channel, $Z ≲0.004$, the radiatively driven winds are strongly reduced as predicted by [ref] and empirically verified by [ref] .
Merging binary black holes formed through chemically homogeneous evolution in short-period stellar binaries · The role of stellar winds: mass loss and angular momentum loss · 0.97
Cites it as background 10 papers
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Although these early results already hinted at the possibility of a corresponding increase in $Ṁ$, such an increase was quantified by [ref] .
X-Shooting ULLYSES: Massive Stars at low metallicity IX: Empirical constraints on mass-loss rates and clumping parameters for OB supergiants in the Large Magellanic Cloud · Introduction · 0.81
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The most widely used prescription for stellar mass loss in the hot upper Hertzsprung–Russell diagram, and a benchmark, is the pioneering work by [ref] , which features a bi-stability jump.
X-Shooting ULLYSES: Massive stars at low metallicity XV. On the metallicity dependence of B-supergiant mass-loss rates · Introduction · 0.85
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In particular, the second bi-stability jump occurring at T $∼$ 8800 K due to the recombination of Fe iii to Fe ii is the most relevant in the context of yellow hypergiants and post-RSG objects [ref] .
Spatial and spectral constraints on resolved mass-loss of the massive Post-RSG star IRAS 17163-3907 and its Fried Egg Nebula · Introduction · 0.82
Discussion
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