MESA (r11554) inlists for the models shown the "Stellar response after stripping as a model ... more MESA (r11554) inlists for the models shown the "Stellar response after stripping as a model for common-envelope outcomes" paper (2107.14526). The inlists reproduce both the pre-stripped and stripped stellar models. Contents: strippedStars_MESA_inlists.zip single_star_evolution<br> - inlist_project<br> - run_star_extras.f stripped_star<br> - inlist_project<br> - run_star_extras.f
Common-envelope (CE) evolution in massive binary systems is thought to be one of the most promisi... more Common-envelope (CE) evolution in massive binary systems is thought to be one of the most promising channels for the formation of compact binary mergers. In the case of merging binary black holes (BBHs), the essential CE phase takes place at a stage when the first BH is already formed and the companion star expands as a supergiant. We aim to decipher the kinds of BH binaries with supergiant companions that could potentially evolve through and survive a CE phase. To this end, we compute envelope binding energies from detailed massive stellar models at different evolutionary stages and metallicities. We make multiple physically extreme choices of assumptions that favor easier CE ejection as well as account for recent advancements in mass-transfer stability criteria. We find that even with the most optimistic assumptions, a successful CE ejection in BH binaries is only possible if the donor is a massive convective-envelope giant, namely a red supergiant (RSG). The same is true for neut...
Luminous red novae (LRNe) are astrophysical transients associated with the partial ejection of a ... more Luminous red novae (LRNe) are astrophysical transients associated with the partial ejection of a binary system’s common envelope shortly before its merger. Here we present the results of our photometric and spectroscopic follow-up campaign of AT 2018bwo (DLT 18x), a LRN discovered in NGC 45, and investigate its progenitor system using binary stellar-evolution models. The transient reached a peak magnitude of Mr = −10.97 ± 0.11 and maintained this brightness during its optical plateau of tp = 41 ± 5 days. During this phase, it showed a rather stable photospheric temperature of ∼3300 K and a luminosity of ∼1040 erg s−1. Although the luminosity and duration of AT 2018bwo is comparable to the LRNe V838 Mon and M31-2015LRN, its photosphere at early times appears larger and cooler, likely due to an extended mass-loss episode before the merger. Toward the end of the plateau, optical spectra showed a reddened continuum with strong molecular absorption bands. The IR spectrum at +103 days aft...
Metallicity is known to significantly affect the radial expansion of a massive star: the lower th... more Metallicity is known to significantly affect the radial expansion of a massive star: the lower the metallicity, the more compact the star, especially during its post-main sequence evolution. Our goal is to study this effect in the context of binary evolution. Using the stellar-evolution code MESA, we computed evolutionary tracks of massive stars at six different metallicities between 1.0 Z⊙ and 0.01 Z⊙. We explored variations of factors known to affect the radial expansion of massive stars (e.g., semiconvection, overshooting, or rotation). Using observational constraints, we find support for an evolution in which already at a metallicity Z ≈ 0.2 Z⊙ massive stars remain relatively compact (∼100 R⊙) during the Hertzprung-gap (HG) phase and most of their expansion occurs during core-helium burning (CHeB). Consequently, we show that metallicity has a strong influence on the type of mass transfer evolution in binary systems. At solar metallicity, a case-B mass transfer is initiated short...
Proceedings of the International Astronomical Union
X-ray binaries with black hole (BH) accretors and massive star donors at short orbital periods of... more X-ray binaries with black hole (BH) accretors and massive star donors at short orbital periods of a few days can evolve into close binary BH (BBH) systems that merge within the Hubble time. From an observational point of view, upon the Roche-lobe overflow such systems will most likely appear as ultra-luminous X-ray sources (ULXs). To study this connection, we compute the mass transfer phase in systems with BH accretors and massive star donors (M > 15 Mʘ) at various orbital separations and metallicities. In the case of core-hydrogen and core-helium burning donors (cases A and C of mass transfer) we find the typical duration of super-Eddington mass transfer of up to 106 and 105 yr, with rates of 10−6 and 10−5Mʘ yr-1, respectively. Given that roughly 0.5 ULXs are found per unit of star formation rate, we estimate the rate of BBH mergers from stable mass transfer evolution to be at most 10 Gpc−3 yr−1.
MESA (r11554) inlists for the models shown the "Stellar response after stripping as a model ... more MESA (r11554) inlists for the models shown the "Stellar response after stripping as a model for common-envelope outcomes" paper (2107.14526). The inlists reproduce both the pre-stripped and stripped stellar models. Contents: strippedStars_MESA_inlists.zip single_star_evolution<br> - inlist_project<br> - run_star_extras.f stripped_star<br> - inlist_project<br> - run_star_extras.f
Common-envelope (CE) evolution in massive binary systems is thought to be one of the most promisi... more Common-envelope (CE) evolution in massive binary systems is thought to be one of the most promising channels for the formation of compact binary mergers. In the case of merging binary black holes (BBHs), the essential CE phase takes place at a stage when the first BH is already formed and the companion star expands as a supergiant. We aim to decipher the kinds of BH binaries with supergiant companions that could potentially evolve through and survive a CE phase. To this end, we compute envelope binding energies from detailed massive stellar models at different evolutionary stages and metallicities. We make multiple physically extreme choices of assumptions that favor easier CE ejection as well as account for recent advancements in mass-transfer stability criteria. We find that even with the most optimistic assumptions, a successful CE ejection in BH binaries is only possible if the donor is a massive convective-envelope giant, namely a red supergiant (RSG). The same is true for neut...
Luminous red novae (LRNe) are astrophysical transients associated with the partial ejection of a ... more Luminous red novae (LRNe) are astrophysical transients associated with the partial ejection of a binary system’s common envelope shortly before its merger. Here we present the results of our photometric and spectroscopic follow-up campaign of AT 2018bwo (DLT 18x), a LRN discovered in NGC 45, and investigate its progenitor system using binary stellar-evolution models. The transient reached a peak magnitude of Mr = −10.97 ± 0.11 and maintained this brightness during its optical plateau of tp = 41 ± 5 days. During this phase, it showed a rather stable photospheric temperature of ∼3300 K and a luminosity of ∼1040 erg s−1. Although the luminosity and duration of AT 2018bwo is comparable to the LRNe V838 Mon and M31-2015LRN, its photosphere at early times appears larger and cooler, likely due to an extended mass-loss episode before the merger. Toward the end of the plateau, optical spectra showed a reddened continuum with strong molecular absorption bands. The IR spectrum at +103 days aft...
Metallicity is known to significantly affect the radial expansion of a massive star: the lower th... more Metallicity is known to significantly affect the radial expansion of a massive star: the lower the metallicity, the more compact the star, especially during its post-main sequence evolution. Our goal is to study this effect in the context of binary evolution. Using the stellar-evolution code MESA, we computed evolutionary tracks of massive stars at six different metallicities between 1.0 Z⊙ and 0.01 Z⊙. We explored variations of factors known to affect the radial expansion of massive stars (e.g., semiconvection, overshooting, or rotation). Using observational constraints, we find support for an evolution in which already at a metallicity Z ≈ 0.2 Z⊙ massive stars remain relatively compact (∼100 R⊙) during the Hertzprung-gap (HG) phase and most of their expansion occurs during core-helium burning (CHeB). Consequently, we show that metallicity has a strong influence on the type of mass transfer evolution in binary systems. At solar metallicity, a case-B mass transfer is initiated short...
Proceedings of the International Astronomical Union
X-ray binaries with black hole (BH) accretors and massive star donors at short orbital periods of... more X-ray binaries with black hole (BH) accretors and massive star donors at short orbital periods of a few days can evolve into close binary BH (BBH) systems that merge within the Hubble time. From an observational point of view, upon the Roche-lobe overflow such systems will most likely appear as ultra-luminous X-ray sources (ULXs). To study this connection, we compute the mass transfer phase in systems with BH accretors and massive star donors (M > 15 Mʘ) at various orbital separations and metallicities. In the case of core-hydrogen and core-helium burning donors (cases A and C of mass transfer) we find the typical duration of super-Eddington mass transfer of up to 106 and 105 yr, with rates of 10−6 and 10−5Mʘ yr-1, respectively. Given that roughly 0.5 ULXs are found per unit of star formation rate, we estimate the rate of BBH mergers from stable mass transfer evolution to be at most 10 Gpc−3 yr−1.
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Papers by Jakub Klencki