The Formation of a 70 M<sub>⊙</sub> Black Hole at High Metallicity

Belczyński, Krzysztof; Hirschi, Raphaël; Kaiser, Etienne A.; Liu, Jifeng; Casares, J.; Lu, Youjun; O’Shaughnessy, R.; Heger, Alexander; Justham, Stephen; Soria, Roberto

doi:10.3847/1538-4357/ab6d77

Cited by 74 publications

(50 citation statements)

References 69 publications

(71 reference statements)

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“…Derived black-hole masses turn out to be relatively high, 25M , which, with current wind prescriptions, can only be created in low metallicity environments. With lower values of the mass-loss rate during the evolution of the star, such as proposed here in this paper (or as in magnetic massive stars, Petit et al 2017), the 'heavy' black holes as detected by gravitational waves might in principle also be produced in highmetallicity environments (Belczynski et al 2020). So far though, in the Galaxy, no observations of such heavy mass black holes (from single stars) exist as all of them have a mass less than 15M (as found in studies such as Shaposhnikov & Titarchuk 2007;Torres et al 2020).…”

Section: Implications For Stellar Evolutionmentioning

confidence: 78%

New predictions for radiation-driven, steady-state mass-loss and wind-momentum from hot, massive stars

Björklund

Sundqvist

Puls

et al. 2021

A&A

114

103

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Context. Reliable predictions of mass-loss rates are important for massive-star evolution computations. Aims. We aim to provide predictions for mass-loss rates and wind-momentum rates of O-type stars, while carefully studying the behaviour of these winds as functions of stellar parameters, such as luminosity and metallicity. Methods. We used newly developed steady-state models of radiation-driven winds to compute the global properties of a grid of O-stars. The self-consistent models were calculated by means of an iterative solution to the equation of motion using full non-local thermodynamic equilibrium radiative transfer in the co-moving frame to compute the radiative acceleration. In order to study winds in different galactic environments, the grid covers main-sequence stars, giants, and supergiants in the Galaxy and both Magellanic Clouds. Results. We find a strong dependence of mass-loss on both luminosity and metallicity. Mean values across the grid are Ṁ~L*2.2 and Ṁ~L*0.95; however, we also find a somewhat stronger dependence on metallicity for lower luminosities. Similarly, the mass loss-luminosity relation is somewhat steeper for the Small Magellanic Cloud (SMC) than for the Galaxy. In addition, the computed rates are systematically lower (by a factor 2 and more) than those commonly used in stellar-evolution calculations. Overall, our results are in good agreement with observations in the Galaxy that properly account for wind-clumping, with empirical Ṁ versus Z* scaling relations and with observations of O-dwarfs in the SMC. Conclusions. Our results provide simple fit relations for mass-loss rates and wind momenta of massive O-stars stars as functions of luminosity and metallicity, which are valid in the range Teff = 28 000–45 000 K. Due to the systematically lower values for Ṁ, our new models suggest that new rates might be needed in evolution simulations of massive stars.

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Section: Implications For Stellar Evolutionmentioning

confidence: 78%

New predictions for radiation-driven, steady-state mass-loss and wind-momentum from hot, massive stars

Björklund

Sundqvist

Puls

et al. 2021

A&A

114

103

View full text Add to dashboard Cite

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“…Based on observations made with the Mercator Telescope, operated on the island of La Palma by the Flemish Community, at the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrofísica de Canarias, and on observations made with the FEROS spectrograph attached to the 2.2 m MPG/ESO telescope at the La Silla observatory. a problem that has been addressed by a series of recent studies (Groh et al 2019;Eldridge et al 2020;Safarzadeh et al 2019;Belczynski et al 2020).…”

Section: Introductionmentioning

confidence: 99%

The “hidden” companion in LB-1 unveiled by spectral disentangling

Shenar

Bodensteiner

Abdul-Masih

et al. 2020

A&A

127

144

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Context. The intriguing binary LS V +22 25 (LB-1) has drawn much attention following claims of it being a single-lined spectroscopic binary with a 79-day orbit comprising a B-type star and a ≈70 M⊙ black hole – the most massive stellar black hole reported to date. Subsequent studies demonstrated a lack of evidence for a companion of such great mass. Recent analyses have implied that the primary star is a stripped He-rich star with peculiar sub-solar abundances of heavy elements, such as Mg and Fe. However, the nature of the secondary, which was proposed to be a black hole, a neutron star, or a main sequence star, remains unknown. Aims. Based on 26 newly acquired spectroscopic observations secured with the HERMES and FEROS spectrographs covering the orbit of the system, we perform an orbital analysis and spectral disentangling of LB-1 to elucidate the nature of the system. Methods. To derive the radial velocity semi-amplitude K2 of the secondary and extract the spectra of the two components, we used two independent disentangling methods: the shift-and-add technique and Fourier disentangling with FDBinary. We used atmosphere models to constrain the surface properties and abundances. Results. Our disentangling and spectral analysis shows that LB-1 contains two components of comparable brightness in the optical. The narrow-lined primary, which we estimate to contribute ≈55% in the optical, has spectral properties that suggest that it is a stripped star: it has a small spectroscopic mass (≈1 M⊙) for a B-type star and it is He- and N-rich. Unlike previous reports, the abundances of heavy elements are found to be solar. The “hidden” secondary, which contributes about 45% of the optical flux, is a rapidly rotating (vsini ≈ 300 km s−1) B3 V star with a decretion disk – a Be star. As a result of its rapid rotation and dilution, the photospheric absorption lines of the secondary are not readily apparent in the individual observations. We measure a semi-amplitude for this star of K2 = 11.2 ± 1.0 km s−1 and adopting a mass of M2 = 7 ± 2 M⊙ typical for B3 V stars, we derive an orbital mass for the stripped primary of M1 = 1.5 ± 0.4 M⊙. The orbital inclination of 39 ± 4° implies a near-critical rotation for the Be secondary (veq ≈ 470 km s−1). Conclusions. LB-1 does not contain a compact object. Instead, it is a rare Be binary system consisting of a stripped star (the former mass donor) and a Be star rotating at near its critical velocity (the former mass accretor). This system is a clear example that binary interactions play a decisive role in the production of rapid stellar rotators and Be stars.

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“…PISNe and PPSNe have a strong imprint upon the BH mass spectrum, as these processes are expected to yield a prominent "gap" in BH mass between roughly 40 and 120 M e for BHs formed through single star evolution (e.g., Belczynski et al 2016a;Spera & Mapelli 2017). While the upper and lower boundaries of this mass gap are uncertain and depend upon various assumptions concerning the evolution of massive stars (e.g., Belczynski et al 2016a;Spera & Mapelli 2017;Woosley 2017;Giacobbo et al 2018;Limongi & Chieffi 2018;Farmer et al 2019;Marchant et al 2019;Stevenson et al 2019;Belczynski et al 2020;Mapelli et al 2020;Renzo et al 2020), studies of the first few GW events seems to corroborate, in general, the theoretical predictions of this mass gap (Fishbach & Holz 2017;Talbot & Thrane 2018;The LIGO Scientific Collaboration et al 2019a).…”

Section: Introductionmentioning

confidence: 99%

Populating the Upper Black Hole Mass Gap through Stellar Collisions in Young Star Clusters

Kremer

Spera

Becker

et al. 2020

ApJ

146

117

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Theoretical modeling of massive stars predicts a gap in the black hole (BH) mass function above ∼40-50 M e for BHs formed through single star evolution, arising from (pulsational) pair-instability supernovae (PISNe). However, in dense star clusters, dynamical channels may exist that allow construction of BHs with masses in excess of those allowed from single star evolution. The detection of BHs in this so-called "upper-mass gap" would provide strong evidence for the dynamical processing of BHs prior to their eventual merger. Here, we explore in detail the formation of BHs with masses within or above the pair-instability gap through collisions of young massive stars in dense star clusters. We run a suite of 68 independent cluster simulations, exploring a variety of physical assumptions pertaining to growth through stellar collisions, including primordial cluster mass segregation and the efficiency of envelope stripping during collisions. We find that as many as ∼20% of all BH progenitors undergo one or more collisions prior to stellar collapse and up to ∼1% of all BHs reside within or above the pair-instability gap through the effects of these collisions. We show that these BHs readily go on to merge with other BHs in the cluster, creating a population of massive BH mergers at a rate that may compete with the "multiple-generation" merger channel described in other analyses. This has clear relevance for the formation of very massive BH binaries as recently detected by the Laser Interferometer Gravitational-Wave Observatory/Virgo in GW190521. Finally, we describe how stellar collisions in clusters may provide a unique pathway to PISNe and briefly discuss the expected rate of these events and other electromagnetic transients.

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The Formation of a 70 M_⊙ Black Hole at High Metallicity

Cited by 74 publications

References 69 publications

New predictions for radiation-driven, steady-state mass-loss and wind-momentum from hot, massive stars

New predictions for radiation-driven, steady-state mass-loss and wind-momentum from hot, massive stars

The “hidden” companion in LB-1 unveiled by spectral disentangling

Populating the Upper Black Hole Mass Gap through Stellar Collisions in Young Star Clusters

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The Formation of a 70 M⊙ Black Hole at High Metallicity

Cited by 74 publications

References 69 publications

New predictions for radiation-driven, steady-state mass-loss and wind-momentum from hot, massive stars

New predictions for radiation-driven, steady-state mass-loss and wind-momentum from hot, massive stars

The “hidden” companion in LB-1 unveiled by spectral disentangling

Populating the Upper Black Hole Mass Gap through Stellar Collisions in Young Star Clusters

Contact Info

Product

Resources

About

The Formation of a 70 M_⊙ Black Hole at High Metallicity