Mass Loss: Its Effect on the Evolution and Fate of High-Mass Stars

“Since massive stars have short lifetimes, their ultraviolet (UV) radiation (reprocessed in various forms) is the most observable tracer of star formation and is used to calculate the star formation rates (Kennicutt 1998, Kennicutt & Evans 2012).”

“Perhaps new open-source codes like MESA (Paxton et al. 2011) will facilitate this.”

“This single-star paradigm then permitted one to extend even further, to compute models for the collective radiative output of entire stellar populations as a function of age (e.g., codes like starburst99; Leitherer et al. 1999).”

“Later, estimates for the solar wind (Parker 1958) powered by hot gas pressure had such low mass-loss rates that winds would not matter much in stellar evolution.”

“Since massive stars have short lifetimes, their ultraviolet (UV) radiation (reprocessed in various forms) is the most observable tracer of star formation and is used to calculate the star formation rates (Kennicutt 1998, Kennicutt & Evans 2012).”

“They leave behind exotic corpses such as black holes, neutron stars, pulsars, magnetars, and all the bizarre high-energy phenomena that occur when compact objects remain bound in a binary system (e.g., Remillard & McClintock 2006).”

“The fact that GRB progenitors have shed most of their envelopes while still retaining a great deal of angular momentum (MacFadyen & Woosley 1999) would seem to strongly favor their origin in binary evolution with mass transfer to spin up the star, or even a merger.”

“…very massive, and they made the first SNe, the first stellar mass black holes, the first dust, ejected the first metals back into the ISM, enhanced or dominated reionization, and probably triggered the formation of the earliest generations of low-mass stars (Bromm & Larson 2004, Heger et al. 2003).”

“…from several young clusters suggest that, when corrected for obervational bias, the fraction of massive stars in binary systems whose orbital period is so short that the stars must exhange mass or merge is something like 3/4 (Kiminki & Kobulnicky 2012, Kobulnicky & Fryer 2007, Sana et al. 2012).”

“…stars are close to their Eddington limit, i.e. the limit on the hydrostatic stability of stars given by the balance between the inward-directed gravitational force and the outward-directed radiative force (Lamers & Fitzpatrick 1988; Maeder 1992; Humphreys & Davidson 1994; Langer 2012; Smith 2014).”

“…stars in a binary system is a common occurrence (e.g., Sana et al. 2012), with implications for a number of topics in stellar evolution (e.g., Podsiadlowski et al. 2004; de Mink et al. 2014; De Marco & Izzard 2017) and energetic transients (e.g., Soker & Tylenda 2006; Chevalier 2012; Smith 2014).”

“Before an SN explodes, the massive star progenitor may suffer from certain degree of envelope stripping either by binary evolution or stellar wind, or the combination of both (Heger et al. 2003; Groh et al. 2013; Smith 2014; Yoon 2015; Fang et al. 2019).”

“During the giant eruptions, they increase their bolometric luminosities for months to years accompanied by extreme mass-loss (Smith 2014).”

“Mass loss in massive stars (MZAMS & 8M ) is among the most poorly understood aspects of stellar evolution (Smith 2014), and core-collapse supernovae (CCSNe) provide a complementary window into studying massloss processes that the stars of the Milky Way and its satellites cannot provide.”

“Some of these massive stars lose their hydrogen and/or helium envelopes before explosion, either through winds or interaction with a binary companion (e.g., Heger et al. 2003; Smith 2014).”

“However, we need to address gaps in our understanding of mass loss from massive stars (Smith 2014) before we can quantify systematic errors and rely on the accuracy of such a measurement.”

“…stars in numerical simulations depends on many different physical parameters that are related to the efficiency of convective energy transport, convective overshoot, semiconvection, rotation, mass loss, binarity, and metallicity, among others (e.g., Maeder & Meynet 2000; Langer 2012; Smith 2014).”

“…to Vink, de Koter & Lamers (2001) for the MS phase, and according to de Jager, Nieuwenhuijzen & van der Hucht (1988) during the evolved supergiant phase, and we apply a multiplicative factor η to the mass loss at all times (see, e.g., Smith 2014; Renzo et al. 2017, on mass loss in massive stars).”

“The majority of core-collapse SNe are Type II, which exhibit Hydrogen (H) emission lines in their optical spectra and in most cases are likely the last evolutionary stage of red supergiants (RSG; Smith 2014).”

“…mass loss at rates exceeding 105 M⊙ yr −1 (although exact mass-loss rates are highly uncertain; Maeder & Meynet 1987; Hamann et al. 1995; Smith 2014), and so observational and theoretical evidence suggest that some pre-SN WR stars ought to be hydrogen- and helium-deficient…”

“The mass loss of massive stars dominates their evolution and determines their fate (Smith 2014).”

“First, the most massive ZAMS star (∼ 100 M ) evolves and loses a fraction of its mass due to winds (see Smith 2014, for a comprehensive review), and then explodes to form a ∼ 50 M BH.”

“The composition and distribution of this material contain information about the mass-loss process, as many of the binary stripping scenarios couple the phases of mass-transfer to the original binary separation (e.g., Smith 2014).”

“The mechanisms responsible for mass-loss, such as radiation-driven winds and eruptions, are not fully understood and they can have a critical impact on the evolution, the nucleosynthesis, and on the final fate of massive stars (e.g., [50,51]).”

“…a class of supernova (“Type IIn”) whose progenitors undergo eruptions (ejecting 0.01–1Me of material) in the years immediately preceding core-collapse (Smith 2014, and references therein) plus the identification in nearby galaxies of relatively lowluminosity transients (“supernova impostors”),…”

“They are thought to originate from the deaths of very massive stars that have lost a considerable amount of their envelope through episodic mass-loss (GalYam et al. 2007; Taddia et al. 2013, see also Smith 2014).”

“While it is generally accepted that this process will scale with both the luminosity of the star and its metallicity (as UV absorption lines are required to absorb photons), many of the details remain uncertain (see [9] for a comprehensive review).”

“Wind mass-loss rates M are still considerably uncertain and could in reality be lower or higher compared to what is assumed in our models (Smith 2014).”

“INTRODUCTION The effects of binarity and the role of mass loss in the decades to years preceding the terminal explosion are among the least understood aspects of massive stellar evolution (e.g. Langer 2012, Smith 2014 for recent reviews).”

“Outbursts of this sort are usually associated with Luminous Blue Variables (LBVs) for which eruptions are considered a natural part of their evolution, despite the exact physics responsible for them is poorly known (Smith 2014).”

“…is mounting from observations of interacting (Type IIn) SNe that their progenitors undergo extreme episodes of mass-loss shortly before core collapse, creating dense circumstellar material (CSM; see review by Smith 2014), but exactly what mechanism is powering these death throes remains unclear.”

“Supergiant systems and luminous blue variables (LBV) can also exhibit mass loss rates in excess of 10−6 M yr−1 (Smith 2014), and therefore for a binary system in a moderately close orbit the compact object can capture enough matter to sustain super-Eddington accretion.”

“…physical processes that trigger and drive the large outbursts remain unexplained, yet are undoubtedly a critical component of the post-main-sequence evolution of massive stars, providing a potential pathway to the Wolf–Rayet phase (see Smith 2014 for a review; but also see Smith & Tombleson 2014).”

“For progenitors experiencing mass loss, stellar winds may strip the H-rich envelope, and possibly some of the He-rich envelope, prior to core-collapse (e.g., Smith 2014; Renzo et al. 2017).”

“They can achieve the highest mass-loss rates of any known types of stars, and they exhibit a wide diversity of irregular and eruptive variability (Conti 1984; Humphreys & Davidson 1994; van Genderen 2001; Clark et al. 2005a; Smith et al. 2004; Smith & Owocki 2006; Smith et al. 2011; Smith 2014).”

“While Woosley & Heger (2006) observe that only 1% of massive stars may reach the rapid rotation regime, there are high uncertainties in the stellar mass loss and magnetic braking calculations (Smith 2014).”

“In binary model systems for SE SNe, the mass-loss rate (and the potential for the presence of a dense CSM) is driven by the binary interactions (e.g., Smith 2014).”

“Several explanations have been proposed to explain these observations, ranging from Luminous Blue Variable-like eruptions (e.g., Smith & Owocki 2006; Smith 2014), to stellar H-envelope ejection as a result of binary interaction (e.g., Podsiadlowski et al. 1992), to internal gravity wave driven mass…”

“Massive stars play a role in the formation of the elements through their ejection of processed material in their winds (Kudritzki & Puls 2000; Vink et al. 2001; Crowther 2007; Smith 2014) and the ejecta from core-collapse supernovae (CCSNe; Maeder 1992; Rauscher et al. 2002; Heger et al. 2003).”

“Alternative explanations other than eruptive mass loss for the lack of RSGs above 20 − 30 M ⊙ include envelope inflation (e.g., Sanyal et al. 2015, 2017) and binary interactions (e.g., Smith 2014; Morozova et al. 2015; Margutti et al. 2017).”

“…extreme case of SN 2006gy requires a mass-loss rate of the order of ∼1 Me yr−1, which is obviously beyond the normal rates inferred from Galactic massive stars (e.g., Hamann et al. 2006; Sander et al. 2012; Smith 2014) and cannot be explained by the current standard theory of steady stellar winds.”

“The average mass-loss rate is∼0.15Me yr −1, or even higher if the wind velocity is higher, lying well in the range of LBV eruptions (Smith 2014).”

“Over the past few decades observations of core-collapse supernovae (CCSNe) ranging from radio to X-rays have revealed that massive stars may undergo enhanced or eruptive mass loss in the final years and decades prior to core collapse (e.g., Smith 2014).”

“However, the mass-loss rates of red supergiants (RSGs) and the role of eruptive mass-loss remain unclear, and the influence on stellar evolution remains uncertain (Smith & Owocki 2006; Smith 2014).”

“Mass loss environment Mass loss is a key process in stellar evolution, and thus is a powerful probe of the progenitor systems of SNe (Puls et al. 2008; Smith 2014).”

“…/m nras/article-abstract/485/1/988/5333346 by U niversity of O xford - Bodleian Library user on 15 M arch 2019 eLBV’s (see review by Smith 2014, and references therein), the explosive mass-loss likely interacts with a more prolonged, quasisteady, enhanced wind outflow prior to…”

“Recently, evidence has been accumulating that some massive stars experience the enhanced mass loss (M M10 yr4 1 - -˙ ) just prior (∼year—decades) to their demise (see Smith 2014, and references therein).”

“This corresponds to a DPR of ∼ 10−7−10−5 M yr−1 for an LBV assuming a lifetime of ∼ 104 yr (Smith 2014), which is comparable to the upper DPR range of WC dustars.”

“Most Type cIIb/Ibc SNe arise from explosions of tidally-stripped binary progenitors with main-sequence masses less than ∼ 25M rather than from explosions of the classical Wolf-Rayet stars originating in more massive stars (Smith 2014).”

“The progenitors for IIn showing signs of slower wind velocities (40–100 km s−1) and smaller mass-loss rates (10−4–10−3 M yr−1) are likely extreme red supergiant (RSG) or yellow hypergiant (YHG) progenitors (Smith 2014).”

“…that precede SNe (Foley et al. 2007; Pastorello et al. 2007; Fraser et al. 2013, 2015; Humphreys et al. 2012; Mauerhan et al. 2013; Ofek et al. 2013) and mass-loss rates ∼ 0.001− 1M yr−1 inferred from observations of circumstellar interaction in Type IIn SNe (e.g., Kiewe et al. 2012; Smith 2014).”

“LBVs have a large range of possible mass-loss rates stemming from quiescent stellar winds or eruptions, from 10−5 M yr−1 to 1 M yr−1 (Smith 2014).”

“Based on the massive star models in the literature (Smith 2014; A19, page 13 of 22 Brott et al. 2011; Vink et al. 2001) and considering that the wind mass-loss rates for these very massive stars cannot be predicted to better than within a factor of ∼2 (with some of this coming from the metallicity…”

“It is known that massive stars lose large amounts of material during their life-times through strong winds or eruptive events ( ÛM > 10−6 M yr−1; Smith 2014; Mauron & Josselin 2011; Vink et al. 2001; Crowther 2007; Groh 2014a).”

“…of faster Wolf-Rayet winds with the slower winds of the red supergiant phase coupled with a shorter-than expected Wolf-Rayet phase; envelope ejection due to binary interaction; or mass shedding due to gravity-wave powered mass loss (e.g., Smith 2014, Zhao & Fuller 2020, Wu & Fuller 2021).”

“Super-nova progenitor stars typically lose significant mass to stellar winds over their lifetime (Vink et al. 2001; Langer 2012; Smith 2014; Woosley et al. 2021).”

“LBVs undergoing a giant eruption (Smith 2014) would be needed to satisfy the required massloss rates, which would exceed 1 × 10−3M⊙ yr −1 for LBV wind velocities at 4.0 × 1016 cm.”

“There are two main mechanisms that can give rise to significant envelope stripping: line-driven winds from isolated massive stars (e.g., Conti 1976; Smith 2014) or binary mass transfer (e.g., Iben & Tutukov 1985; Yoon et al. 2010; Claeys et al. 2011; Yoon 2015).”

“SN IIn progenitors are generally thought to be massive stars (like luminous blue variables, LBVs) that lose their hydrogen envelopes to wind- driven mass loss and outbursts (Gal-Yam et al. 2007; Gal-Yam & Leonard 2009; Kiewe et al. 2012; Taddia et al. 2013; Smith 2014).”

“The colored regions correspond to values for various evolved massive stars from [1, 30], including the AGB, super-AGB, RSG, extreme RSG (eRSG), yellow supergiants (YSG), YHG, luminous blue variable (LBV) winds, LBV giant eruptions, and binary Roche-lobe overflow (RLOF).”

“…radiative properties of the shock front are directly dependent on the circumstellar density, radio/X-ray observations also probe the mass-loss history of the progenitor star in the years prior to explosion, a phase in stellar evolution that is poorly understood (see Smith 2014 for a recent review).”

“The lower limit corresponds to a weak wind for a late O-type or an early B-type star (Puls et al. 2008; Smith 2014).”

“Using an O-type stellar wind luminosity of ∼ 1049−51 ergs in a lifetime of 5 Myr (Leitherer et al. 1999; Smith 2014; Ramachandran et al. 2019) and assuming O-type stars comprise 0.2% of the total number of stars formed (Kroupa initial mass function), we can calculate the total energy output over…”

“Because these lines appear soon after the SN explosion, it is expected that the shell of circumstellar matter (CSM) was ejected by the star within a few years before the SN explosion itself (Smith 2014).”

“This prescription is argued to over-estimate the mass-loss rate (e.g., Smith 2014).”

“…naturally accounts for the discrepancy between the large inferred rate of SESNe compared to massive WR stars (Georgy et al. 2009; Smith et al. 2011; Eldridge et al. 2013; Smith 2014), and for the low ejecta masses inferred from the modeling of the bolometric light-curves of type Ibc SNe (Mej .”

“For wind mass loss, we use the “Dutch” wind scheme in MESA (Glebbeek et al. 2009), reduced by multiplication with a factor of 0.3 (Puls et al. 2008; Smith 2014).”

“Such an effect could provide an additional energy source that makes the explosions brighter and cause the early spectra of the transients to look like SNe IIn (e.g., Chatzopoulos et al. 2013; Smith 2014; Liu et al. 2018).”

“A fraction of massive stars undergo strongly enhanced mass loss near the very ends of their lives, forming a dense circumstellar medium (CSM) around themselves (e.g., Smith 2014).”

“M ⊙ (Smartt et al. 2009; Smith 2014; Smartt 2015; Smith 2017) and not at these lower masses (however, see Beasor et al. (2024b)) .”

“The repeating brief luminosity spikes in 2009-2011 we also attributed to binary close encouters (Mauerhan et al. 2013, 2014; Smith 2014), either through direct stellar collisions at periaston in an eccentric system as in the η Car system (Smith 2011) or potentially due to periastron accretion…”

“…(Piro 2015) 7 p r=˙ ( )M r r v4 2 w, where ρ(r) is the average density at a radius r, and vw≈ 100–1000 km s−1 is the terminal velocity of stellar wind of a hydrogen-poor star (He star; Smith 2014). and energy injection from a magnetar or an ejecta-CSM interaction to fit the LC of iPTF13dcc.”

“Particularly, Puls et al. (2008) and Smith (2014) suggest that the algorithms are overestimated by a factor of three (see also Renzo et al. 2017, for details).”

“Smith (2014) classified eruptive mass loss into super-Eddington winds and non-terminal explosions.”

“…are poorly understood, winds (Puls et al. 2008), episodic ejections (Smith & Owocki 2006; Pastorello et al. 2007; Shiode & Quataert 2014), binary interactions (Smith 2014), and common-envelope formation and ejection (Chugai & Chevalier 2006; Chevalier 2012) are some of the favored scenarios.”

“Both channels result in a Wolf−Rayet star that loses its remaining envelope through line-driven winds (Smith 2014; Yoon 2017), but their relative roles in driving type-Ic and type-Ib (in which only hydrogen has been stripped) explosions remain unknown.”

“If the mass-loss velocity is vw∼ 10 km s −1 for the extended progenitors of SNe II (mainly red supergiants; RSGs; Smith 2014; Moriya et al. 2017), this confined CSM must have been created by the pre-SN activity in the last ∼30 yr, with a corresponding mass-loss rate of∼10−3Me yr −1 (Groh 2014;…”

“We vary the ejecta mass uniformly and randomly between 0.01 – 1.00 M ⊙ , typical of pre-SN outbursts in the time frame that the CSM around SN 2023ixf was formed (e.g., Smith 2014).”

“In particular, the important conjecture that S Dor variations are caused by optically thick winds at constant LBol may be wrong, and steady super-Eddington winds may not be the correct or dominant driving mechanism in many giant LBV eruptions (see review by Smith 2014).”

“On the other hand, large amplitude variability, such as occurs in RSGs and LBVs can alter and/or hasten the subsequent evolution of the star (Heger et al. 1997; Yoon & Cantiello 2010; Owocki 2015; Smith & Owocki 2006; Smith 2014).”

“…as well as on the radiative and mechanical mass loss (e.g. Krtička et al. 2011), which all significantly affect the different predictions and outputs of the 1D stellar evolution models (e.g. Meynet & Maeder 2000; Maeder & Meynet 2000, 2010; Smith 2014; Meynet et al. 2015; Renzo et al. 2017).”

“Throughout their lives, massive stars shed mass through steady winds, but these winds can be punctuated by episodic mass loss events (Smith 2014).”

“These prominent lines likely originate in dense circumstellar material (CSM) that was ejected shortly before the SN explosion itself (see Smith 2014 for a review of pre-SN mass loss).”

“Kudritzki & Puls (2000), Puls et al. (2008), and Smith (2014) provide comprehensive reviews of massive star winds and mass loss.”

“Note that envelope removal will typically lead to lowluminosity W-R stars of high-Z and/or high-luminosity (and subsequently high mass) owing to a thin hydrogen layer remaining, which requires removal from sufficiently high stellar winds (Smith 2014; Trani et al. 2014, and references therein).”