New self-consistent wind parameters to fit optical spectra of O-type stars observed with the HERMES spectrograph

Gormaz-Matamala, A. C.; Curé, M.; Lobel, A.; Panei, J. A.; Cuadra, Jorge; Araya, I.; Arcos, C.; Figueroa-Tapia, Felipe

doi:10.1051/0004-6361/202142383

Cited by 10 publications

(8 citation statements)

References 81 publications

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“…This iterative procedure is hereafter named m-CAK prescription, it was introduced in Gormaz- Matamala et al (2019) and it has demonstrated to provide values for Ṁ of the same order of magnitude than those obtained with self-consistent NLTE studies in the comoving frame such as Krtička & Kubát (2017 or Gormaz-Matamala et al (2021). Moreover, the wind hydrodynamics used as input in the NLTE radiative transport code is able to reproduce reliable synthetic spectra, in agreement with the observations (Gormaz-Matamala et al 2022a).…”

Section: Self-consistent Evolution Modelsmentioning

confidence: 57%

“…We have extended the stellar evolution models performed in Gormaz-Matamala et al (2022b, Paper I), adopting selfconsistent m-CAK prescription (Gormaz-Matamala et al 2019, 2022a for the mass loss rate recipe (Eq. 1), by including the rotational effects.…”

Section: Discussionmentioning

confidence: 99%

“…Because self-consistent mass loss rates are a factor of ∼ 3 lower with respect to Vink's formula at the beginning of MS (i.e., for T eff 40 kK and log g ∼ 4.0, see Gormaz-Matamala et al 2022a), self-consistent evolution models predict that stars will retain more mass during their H-core burning stage and therefore they are larger and more luminous. These changes are proportional to the initial mass of the star; from important differences in the final stellar properties at the end of MS for M zams = 120 M , to almost negligible differences for M zams = 25 M .…”

Section: Input Stellar Parametersmentioning

confidence: 99%

“…The rotation factor Ω is implicitly included in Eq. 7 by means of φ = rot R * /r, whereas the additional terms are the same as described by Araya et al (2017Araya et al ( , 2021 or Gormaz-Matamala et al (2022a). In this work, we use moderate to intermediate values of Ω (= 0.4), therefore all our wind solutions are in the fast wind regime and not in the Ω-slow wind regime which starts approximately from Ω 0.75 (Araya et al 2018).…”

Section: Enhancing Mass Loss Due To Rotational Effectsmentioning

confidence: 99%

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Evolution of rotating massive stars with new hydrodynamic wind models

Gormaz-Matamala¹,

Cuadra²,

Meynet³

et al. 2023

Preprint

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Context. Mass loss due to radiatively line-driven winds is central to our understanding of the evolution of massive stars in both single and multiple systems. This mass loss plays a key role modulating the stellar evolution at different metallicities, particularly in the case of massive stars with M * ≥ 25 M . Aims. We extend the evolution models introduced in Paper I, where the mass loss recipe is based on the simultaneous calculation of the wind hydrodynamics and the line-acceleration, by incorporating the effects of stellar rotation. Methods. As in Paper I, we introduce a grid of self-consistent line-force parameters (k, α, δ) for a set of standard evolutionary tracks using Genec. Based on this grid, we analyse the effects of stellar rotation, CNO abundances and He/H ratio on the wind solutions, to derive extra terms for the recipe predicting the self-consistent mass loss rate, Ṁsc . With that, we generate a new set of evolutionary tracks with rotation for M ZAMS = 25, 40, 70, and 120 M , and metallicities Z = 0.014 (Galactic) and 0.006 (LMC). Results. Besides the expected correction factor due to rotation, the mass loss rate decreases when the surface become more heliumrich, especially at the later moments of the main sequence phase. The self-consistent approach gives lower mass loss rates than the standard values adopted in previous Genec evolution models. This decrease impacts strongly on the tracks of the most massive models. Weaker winds allow the star to retain more mass, but also more angular momentum. As a consequence at a given age, weaker wind models rotate faster and show a less efficient mixing in their inner stellar structure. Conclusions. The self-consistent tracks predict an evolution of the rotational velocities through the main sequence in close agreement with the range of sin i values found by recent surveys of Galactic O-type stars. As subsequent implications, the weaker winds from self-consistent models also suggest a reduction of the contribution of the isotope 26 Al to the interstellar medium due to stellar winds of massive stars during the MS phase. Moreover, the higher luminosities found for the self-consistent evolutionary models suggest that some populations of massive stars might be less massive than previously thought, as in the case of Ofpe stars at the Galactic Centre. Therefore, this study opens a wide range of consequences for further research based on the evolution of massive stars.

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Section: Self-consistent Evolution Modelsmentioning

confidence: 57%

Section: Discussionmentioning

confidence: 99%

Section: Input Stellar Parametersmentioning

confidence: 99%

Section: Enhancing Mass Loss Due To Rotational Effectsmentioning

confidence: 99%

See 2 more Smart Citations

Evolution of rotating massive stars with new hydrodynamic wind models

Gormaz-Matamala¹,

Cuadra²,

Meynet³

et al. 2023

Preprint

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“…For optically thin winds we adopt the mass-loss rate from Gormaz-Matamala et al (2022b), based on their self-consistent m-CAK prescription (Gormaz-Matamala et al 2019, 2022a…”

Section: Mass-loss Prescriptionmentioning

confidence: 99%

On the Maximum Black Hole Mass at Solar Metallicity

Romagnolo,

Gormaz-Matamala,

Belczynski

2024

ApJL

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In high-metallicity environments the mass that black holes (BHs) can reach just after core collapse widely depends on how much mass their progenitor stars lose via winds. On one hand, new theoretical and observational insights suggest that early-stage winds should be weaker than what many canonical models prescribe. On the other hand, the proximity to the Eddington limit should affect the formation of optically thick envelopes already during the earliest stages of stars with initial masses M ZAMS ≳ 100 M ⊙, hence resulting in higher mass-loss rates during the main sequence. We use the evolutionary codes MESA and Genec to calculate a suite of tracks for massive stars at solar metallicity Z ⊙ = 0.014, which incorporate these changes in our wind-mass-loss prescription. In our calculations we employ moderate rotation, high overshooting, and magnetic angular momentum transport. We find a maximum BH mass M BH , max = 28.3 M ⊙ at Z ⊙. The most massive BHs are predicted to form from stars with M ZAMS ≳ 250 M ⊙, with the BH mass directly proportional to its progenitor’s M ZAMS. We also find in our models that at Z ⊙ almost any BH progenitor naturally evolves into a Wolf–Rayet star due to the combined effect of internal mixing and wind mass loss. These results are considerably different from most recent studies regarding the final mass of stars before their collapse into BHs. While we acknowledge the inherent uncertainties in stellar evolution modeling, our study underscores the importance of employing the most up-to-date physics in BH mass predictions.

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Evolution of massive stars with new hydrodynamic wind models

Gormaz-Matamala

Curé

Meynet

et al. 2022

A&A

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Context. Mass-loss by radiatively line-driven winds is central to our understanding of massive star evolution either single or in multiple systems. It for instance plays a key role in making massive star evolution different at different metallicities, specially in the case of very massive stars (M * ≥ 25M ).Aims. Here we present evolutionary models for a set of massive stars, introducing a new prescription for the mass-loss rate obtained from hydrodynamical calculations in which the wind velocity profile, (r), and the line-acceleration, g line , are obtained in a self consistently way. These new prescriptions cover the most part of the Main-Sequence phase of O-type stars. Methods. We perform a grid of self-consistent mass-loss rates Ṁsc , for a set of standard evolutionary tracks (i.e., using the old prescription for mass-loss rate) under different values for initial mass and metallicity. Based in this grid, we elaborate a statistical analysis to create a new simple formula predicting the values of Ṁsc just from the stellar parameters, without assuming any extra condition for the wind description. Therefore, replacing mass-loss rates at the Main Sequence stage from the standard Vink's formula by our new recipe, we generate a new set of evolutionary tracks for M ZAMS = 25, 40, 70 and 120 M and metallicities Z = 0.014 (Galactic), Z = 0.006 (LMC), and Z = 0.002 (SMC). Results. Our new derived formula for mass-loss rate predicts a dependence Ṁ ∝ Z a , where a is not longer constant but dependent on the stellar mass: ranging from a ∼ 0.53 when M * ∼ 120 M , to a ∼ 1.02 when M * ∼ 25 M . We found important differences between standard and our new self-consistent tracks. Models adopting the new recipe for Ṁ (which starts being around ∼ 3 times weaker than mass-loss rate from the old formulation) retain more mass during their evolution, which is expressed in larger radii and consequently more luminous tracks over the Hertzsprung-Russell diagram. These differences are more prominent for the cases of M ZAMS = 70 and 120 M at solar metallicity, where we found self-consistent tracks are ∼ 0.1 dex brighter and keep extra mass up to 20 M , compared with the classical models using the previous formulation for mass-loss rate. Later increments in the mass-loss rate for tracks when self-consistency is not longer used, attributed to the LBV stage, produce different final stellar radii and masses before the end of H-burning stage, which are analysed case to case. Moreover, we observed remarkable differences for the evolution of the radionuclide isotope 26 Al in the core and the surface of the star. Since Ṁsc are weaker than the commonly adopted values for evolutionary tracks, self-consistent tracks predict a later modification in the abundance number of 26 Al in the stellar winds. This new behaviour could provide useful information about the real contribution of this isotope from massive stars to the Galactic interstellar medium.

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New self-consistent wind parameters to fit optical spectra of O-type stars observed with the HERMES spectrograph

Cited by 10 publications

References 81 publications

Evolution of rotating massive stars with new hydrodynamic wind models

Evolution of rotating massive stars with new hydrodynamic wind models

On the Maximum Black Hole Mass at Solar Metallicity

Evolution of massive stars with new hydrodynamic wind models

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