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

“Light echoes from 16 Smith the Great Eruption of η Carinae have just recently been discovered (Rest et al. 2012), and their continued study with spectroscopy may modify long-held ideas about LBVs.”

“Dust formation in LBV eruptions also points toward eruptive mass loss (Kochanek 2011).”

“SE winds may also account for the bipolar shape of nebulae around LBVs like η Car if the star is a rapid rotator, since equatorial gravity darkening will lead to a higher Ṁ and faster speed in the polar wind (Dwarkadas & Owocki 2002, Owocki et al. 1996).”

“There are also a few reported transitional cases between SNe Ibn and IIn, including SN 2005la and SN 2011hw and 2005la (Pastorello et al. 2008, Smith et al. 2012), suggesting a possible continuum in progenitor H envelope stripping, similar to SNe II-P, IIb, and Ib.”

“Reductions by factors of 2-4 are confirmed by X-ray observations (Cohen et al. 2010, 2011, Kramer et al. 2003).”

“Assuming wind speeds of ∼1000 km s−1, observations suggest a very wide range of mass-loss rates for SN Ibc progenitors, from 10−7M⊙ yr −1 up to values near the line-driving limit, with an average around 10−5 M⊙ yr −1 (Wellons et al. 2012).”

“…& Arnett 2007, Quataert & Shiode 2012, Shiode & Quataert 2013), and stellar collisions or mergers in a binary system (Podsiadlowski et al. 2010, Smith 2011, Smith & Arnett 2014).4 While any of these provides a plausible result, the main criticism for explaining LBV eruptions is that the…”

“Recently it was argued that SN 1961V was actually a true core-collapse SN IIn (Kochanek et al. 2011, Smith et al. 2011a), which would provide evidence for a ∼100 M⊙ LBV-like progenitor that experienced eruptive mass loss before a SN IIn.”

“Consequently, their loosely bound envelopes may be susceptible to strange-mode instabilities (Glatzel & Kiriakidis 1993, Glatzel et al. 1999), runaway mass loss (a.k.a. the “Geyser” model; Humphreys & Davidson 1994, Maeder 1992), or the critical rotation limit (a.k.a. the “Ω limit”; Langer 1998,…”

“Two other SNe IIb, SN 2001ig and SN 2008ax also show possible indications of a companion star (Crockett et al. 2008, Ryder et al. 2006).”

“…collisions (Ofek et al. 2007, Smith & McCray 2007, Smith et al. 2007, 2010b, Woosley et al. 2007), but a number of very luminous SNe IIn have been studied in detail since then, including objects like SN 2006tf (Smith et al. 2008), SN 2003ma (Rest et al. 2011), and SN 2008fz (Drake et al. 2010).”

“SN 2010mc. Ofek et al. (2013b) reported the detection of a precursor event ∼40 d before the peak of the Type IIn SN 2010mc.”

“Smith (2013a) showed that a shock-powered event with CSM interaction could account for the 1845-1860 light curve of η Car, using a SN IIn-type model but with lower explosion energy.”

“…scales; large scales include such complexities as the time-variable discrete absorption components (Cranmer & Owocki 1996, Fullerton et al. 1997, Howarth et al. 1995, Massa et al. 1995), or axisymmetric winds due to rapid rotation (Owocki et al. 1996), and a wide array of magnetically induced…”

“…stars in clusters using radial velocities, which typically find an observed binary fraction of 20-60% (Chini et al. 2012, De Becker et al. 2006, Evans et al. 2006, Garcia & Mermilliod 2001, Gies 1987, Kiminki & Kobulnicky 2012, Kiminki et al. 2012, Mahy et al. 2009, Sana et al. 2008, 2009, 2012).”

“Interestingly, Sanders et al. (2013) report the detection of a SN Ibn in a giant elliptical galaxy with no evidence for ongoing star formation at the explosion site, which challenges the idea that these arise exclusively from very massive progenitor stars.”

“…or decades (like SN 1988Z, Aretxaga et al. 1999) as well as long-lasting IR echoes from distant dust shells illuminated by the SN (Fox et al. 2011, Gerardy et al. 2002) — both of these indicate a considerable amount of mass lost by the progenitor star for centuries before core-collapse, either in…”

“Similarly, Huenemoerder et al. (2012) find from considering X-ray diagnostics that the Ṁ reduction may not be as severe as suggested from UV diagnostics, although their favored rate of Ṁ = 2×10−9 M⊙ yr−1 for the O9.”

“LBVs have been identified in nearby lowZdwarf galaxies (Izotov & Thuan 2009, Izotov et al. 2011), in addition to the very nearby case of HD 5980 in the SMC, and the LBV-like eruptions that precede SNe IIn (see below) often occur in dwarf galaxies.”

“…P Cygni was an LBV. 4Soker and collaborators have discussed a model to power the luminosity in LBV eruptions using accretion onto a companion star (Kashi & Soker 2009), but this invokes an eruption to provide the mass that is then accreted; it does not explain what initiates the mass loss from…”

“It has component masses of roughly 8 and 30 M⊙, with a mass-gainer surrounded by an opaque disk (Grundstrom et al. 2007) and a spatially resolved toroidal nebula (Smith et al. 2011c).”

“…fraction among massive stars in clusters using radial velocities, which typically find an observed binary fraction of 20-60% (Chini et al. 2012, De Becker et al. 2006, Evans et al. 2006, Garcia & Mermilliod 2001, Gies 1987, Kiminki & Kobulnicky 2012, Kiminki et al. 2012, Mahy et al. 2009, Sana et…”

“This makes it hard to explain the nebula around η Car, with most of the mass moving at speeds of 500-600 km s−1.”

“Note that similar considerations of UV diagnostics were noted earlier as well (Cohen et al. 1997, 2008, Drew et al. 1994).”

“Some well studied SNe IIn like SN1998S (Leonard et al. 2000) and SN 2009ip (Levesque et al. 2013, Smith et al. 2014) are consistent with very asymmetric or even disk-like CSM.”

“Reductions by factors of 2-4 are confirmed by X-ray observations (Cohen et al. 2010, 2011, Kramer et al. 2003).”

“Numerical simulations of continuum-driven SE winds show complex structure with both infall and outflow (van Marle et al. 2008, 2009), confirming expectations that these winds should be highly inhomogeneous (Owocki et al. 2004, Shaviv 2000).”

“P Cyg’s nebula has an expansion speed of ∼140 km s−1 (Barlow et al. 1994, Smith & Hartigan 2006), with an implied total kinetic energy of a few 1046 ergs.”

“24 Smith star HR 5171A, which Chesneau et al. (2014) recently resolved as a mass transfer binary using interferometry.”

“Current estimates of the mass lost in η Car’s 19th century eruption are of order 15 M⊙ or more (Smith & Ferland 2007, Smith et al. 2003).”

“…include such complexities as the time-variable discrete absorption components (Cranmer & Owocki 1996, Fullerton et al. 1997, Howarth et al. 1995, Massa et al. 1995), or axisymmetric winds due to rapid rotation (Owocki et al. 1996), and a wide array of magnetically induced inhomogeneities…”

“Note that similar considerations of UV diagnostics were noted earlier as well (Cohen et al. 1997, 2008, Drew et al. 1994).”

“…stars in clusters using radial velocities, which typically find an observed binary fraction of 20-60% (Chini et al. 2012, De Becker et al. 2006, Evans et al. 2006, Garcia & Mermilliod 2001, Gies 1987, Kiminki & Kobulnicky 2012, Kiminki et al. 2012, Mahy et al. 2009, Sana et al. 2008, 2009, 2012).”

“Their inferred histories depend on a number of assumptions, however (Hellings 1984).”

“Numerical simulations of continuum-driven SE winds show complex structure with both infall and outflow (van Marle et al. 2008, 2009), confirming expectations that these winds should be highly inhomogeneous (Owocki et al. 2004, Shaviv 2000).”

“LBVs have been identified in nearby lowZdwarf galaxies (Izotov & Thuan 2009, Izotov et al. 2011), in addition to the very nearby case of HD 5980 in the SMC, and the LBV-like eruptions that precede SNe IIn (see below) often occur in dwarf galaxies.”

“Diverse SLSN light curve shapes are possible, depending on the distribution of the mass and explosion properties (Chatzopoulos & Wheeler 2013, Chevalier & Irwin 2011, Moriya et al. 2013, van Marle et al. 2010).”

“A realization in the past decade is that there is wide diversity among the SN impostors and their progenitors; some events that resemble LBV eruptions may actually arise in lower-mass progenitor stars (Prieto et al. 2008a, Thompson et al. 2009).”

“This, in turn, suggests that influence of rotation and rotational mixing in current single-star models may be overstimated (de Mink et al. 2013, Vanbeveren 2009).”

“Massey (2006) has pointed to the case of P Cygni as a salient example: its 1600 A.D. giant LBV eruption was observed and so we call it an LBV, but it has shown no eruptive LBV-like behavior since then.”

“A possible cause of this inflation of the star’s outer layers may be near-Eddington luminosities in the sub-surface Fe opacity bump (Gräfener et al. 2012, Guzik & Lovekin 2012).”

“There are many ways M & 8 M stars can end their lives 3 (e.g., Woosley et al. 2002; Smartt 2009; Meynet et al. 2010; Langer 2012; Nomoto et al. 2013; Smith 2014).”

“It is frequently cited as one of the most uncertain ingredients in stellar evolution, and is thought to play a crucial role in the advanced stages of stellar evolution for low-mass stars and in all phases of evolution for massive stars (see Smith 2014 for a recent review on this topic).”

“…the formation of the dense molecular clouds and stars (Heyer & Dame 2015); the evolution of stellar populations, their winds and energetic feedback (Smith 2014); the explosions of supernovae (Nomoto, Kobayashi & Tominaga 2013); the formation of supermassive black holes and the interaction of…”