The Explosion of Helium Stars Evolved with Mass Loss
About: This article is published in The Astrophysical Journal.The article was published on 2020-02-12 and is currently open access. It has received 134 citations till now. The article focuses on the topics: Stars & Helium.
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TL;DR: In 2019, the LIGO Livingston detector observed a compact binary coalescence with signal-to-noise ratio 12.9 and the Virgo detector was also taking data that did not contribute to detection due to a low SINR but were used for subsequent parameter estimation as discussed by the authors.
Abstract: On 2019 April 25, the LIGO Livingston detector observed a compact binary coalescence with signal-to-noise ratio 12.9. The Virgo detector was also taking data that did not contribute to detection due to a low signal-to-noise ratio, but were used for subsequent parameter estimation. The 90% credible intervals for the component masses range from to if we restrict the dimensionless component spin magnitudes to be smaller than 0.05). These mass parameters are consistent with the individual binary components being neutron stars. However, both the source-frame chirp mass and the total mass of this system are significantly larger than those of any other known binary neutron star (BNS) system. The possibility that one or both binary components of the system are black holes cannot be ruled out from gravitational-wave data. We discuss possible origins of the system based on its inconsistency with the known Galactic BNS population. Under the assumption that the signal was produced by a BNS coalescence, the local rate of neutron star mergers is updated to 250-2810.
1,189 citations
TL;DR: In this article, the authors present 39 candidate gravitational wave events from compact binary coalescences detected by Advanced LIGO and Advanced Virgo in the first half of the third observing run (O3a) between 1 April 2019 15:00 UTC and 1 October 2019 15.00.
Abstract: We report on gravitational wave discoveries from compact binary coalescences detected by Advanced LIGO and Advanced Virgo in the first half of the third observing run (O3a) between 1 April 2019 15:00 UTC and 1 October 2019 15:00. By imposing a false-alarm-rate threshold of two per year in each of the four search pipelines that constitute our search, we present 39 candidate gravitational wave events. At this threshold, we expect a contamination fraction of less than 10%. Of these, 26 candidate events were reported previously in near real-time through GCN Notices and Circulars; 13 are reported here for the first time. The catalog contains events whose sources are black hole binary mergers up to a redshift of ~0.8, as well as events whose components could not be unambiguously identified as black holes or neutron stars. For the latter group, we are unable to determine the nature based on estimates of the component masses and spins from gravitational wave data alone. The range of candidate events which are unambiguously identified as binary black holes (both objects $\geq 3~M_\odot$) is increased compared to GWTC-1, with total masses from $\sim 14~M_\odot$ for GW190924_021846 to $\sim 150~M_\odot$ for GW190521. For the first time, this catalog includes binary systems with significantly asymmetric mass ratios, which had not been observed in data taken before April 2019. We also find that 11 of the 39 events detected since April 2019 have positive effective inspiral spins under our default prior (at 90% credibility), while none exhibit negative effective inspiral spin. Given the increased sensitivity of Advanced LIGO and Advanced Virgo, the detection of 39 candidate events in ~26 weeks of data (~1.5 per week) is consistent with GWTC-1.
768 citations
TL;DR: In this article, the authors provide an answer to the question "How Were the Elements from Iron to Uranium Made?" (Abridged) by combining new results and important breakthroughs in the related nuclear, atomic and astronomical fields of science.
Abstract: The production of about half of the heavy elements found in nature is assigned to a specific astrophysical nucleosynthesis process: the rapid neutron capture process (r-process). Although this idea has been postulated more than six decades ago, the full understanding faces two types of uncertainties/open questions: (a) The nucleosynthesis path in the nuclear chart runs close to the neutron-drip line, where presently only limited experimental information is available, and one has to rely strongly on theoretical predictions for nuclear properties. (b) While for many years the occurrence of the r-process has been associated with supernovae, more recent studies have cast substantial doubts on this environment. Alternative scenarios include the mergers of neutron stars, neutron-star black hole mergers, but possibly also rare classes of supernovae as well as hypernovae/collapsars with polar jet ejecta and also accretion disk outflows related to the collapse of fast rotating massive stars with high magnetic fields. Stellar r-process abundance observations, have provided insights into, and constraints on the frequency of and conditions in the responsible stellar production sites. One of them, neutron star mergers, was just identified and related to the Gravitational Wave event GW170817. High resolution observations, increasingly more precise due to improved experimental atomic data, have been particularly important in defining the heavy element abundance patterns of the old halo stars, and thus determining the extent, and nature, of the earliest nucleosynthesis in our Galaxy. Combining new results and important breakthroughs in the related nuclear, atomic and astronomical fields of science, this review attempts to provide an answer to the question "How Were the Elements from Iron to Uranium Made?" (Abridged)
321 citations
TL;DR: In this paper, the authors present a critical assessment of the SN1987A supernova cooling bound on axions and other light particles, showing that neutrinos do not cool the disk and do not affect its neutrino output.
Abstract: We present a critical assessment of the SN1987A supernova cooling bound on axions and other light particles. Core collapse simulations used in the literature to substantiate the bound omitted from the calculation the envelope exterior to the proto-neutron star (PNS). As a result, the only source of neutrinos in these simulations was, by construction, a cooling PNS. We show that if the canonical delayed neutrino mechanism failed to explode SN1987A, and if the precollapse star was rotating, then an accretion disk would form that could explain the late-time ($t\ensuremath{\gtrsim}5\text{ }\text{ }\mathrm{sec}$) neutrino events. Such accretion disk would be a natural feature if SN1987A was a collapse-induced thermonuclear explosion. Axions do not cool the disk and do not affect its neutrino output, provided the disk is optically thin to neutrinos, as it naturally is. These considerations cast doubt on the supernova cooling bound.
160 citations
TL;DR: The delayed neutrino-heating mechanism is emerging as the key driver of supernova explosions, but there remain many issues to address, such as the chaos of the involved dynamics.
Abstract: Most supernova explosions accompany the death of a massive star. These explosions give birth to neutron stars and black holes, and eject solar masses of heavy elements. However, determining the mechanism of explosion has been a half-century journey of great numerical and physical complexity. Here we present the status of this theoretical quest and the physics and astrophysics upon which its resolution seems to depend. The delayed neutrino-heating mechanism is emerging as the key driver of supernova explosions, but there remain many issues to address, such as the chaos of the involved dynamics.
120 citations
References
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TL;DR: In this paper, the evolutionary significance of the observed luminosity function for main-sequence stars in the solar neighborhood is discussed and it is shown that stars move off the main sequence after burning about 10 per cent of their hydrogen mass and that stars have been created at a uniform rate in a solar neighborhood for the last five billion years.
Abstract: The evolutionary significance of the observed luminosity function for main-sequence stars in the solar neighborhood is discussed. The hypothesis is made that stars move off the main sequence after burning about 10 per cent of their hydrogen mass and that stars have been created at a uniform rate in the solar neighborhood for the last five billion years. Using this hypothesis and the observed luminosity function, the rate of star creation as a function of stellar mass is calculated. The total number and mass of stars which have moved off the main sequence is found to be comparable with the total number of white dwarfs and with the total mass of all fainter main-sequence stars, respectively.
8,607 citations
TL;DR: In this article, solar photospheric and meteoritic CI chondrite abundance determinations for all elements are summarized and the best currently available photosphere abundances are selected, including the meteoritic and solar abundances of a few elements (e.g., noble gases, beryllium, boron, phosphorous, sulfur).
Abstract: Solar photospheric and meteoritic CI chondrite abundance determinations for all elements are summarized and the best currently available photospheric abundances are selected. The meteoritic and solar abundances of a few elements (e.g., noble gases, beryllium, boron, phosphorous, sulfur) are discussed in detail. The photospheric abundances give mass fractions of hydrogen (X ¼ 0:7491), helium (Y ¼ 0:2377), and heavy elements (Z ¼ 0:0133), leading to Z=X ¼ 0:0177, which is lower than the widely used Z=X ¼ 0:0245 from previous compilations. Recent results from standard solar models considering helium and heavy-element settling imply that photospheric abundances and mass fractions are not equal to protosolar abundances (representative of solar system abundances). Protosolar elemental and isotopic abundances are derived from photospheric abundances by considering settling effects. Derived protosolar mass fractions are X0 ¼ 0:7110, Y0 ¼ 0:2741, and Z0 ¼ 0:0149. The solar system and photospheric abundance tables are used to compute self-consistent sets of condensation temperatures for all elements. Subject headings: astrochemistry — meteors, meteoroids — solar system: formation — Sun: abundances — Sun: photosphere
4,305 citations
"The Explosion of Helium Stars Evolv..." refers background in this paper
...The mass fraction of Mg in the sun is 6.6×10−4 (Lodders 2003), all of which is believed to be made in core-collapse supernovae and WR-winds....
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...Adopting iron and oxygen mass fractions in the sun of 1.37×10−3 and 6.60×10−3 respectively (Lodders 2003), the mass ratio of oxygen to iron in the sun is 4.8....
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Max Planck Society1, McGill University2, University of Toronto3, University of Manchester4, University of Sheffield5, German Aerospace Center6, ASTRON7, University of Amsterdam8, Lebedev Physical Institute9, University of Warwick10, West Virginia University11, University of Virginia12, National Radio Astronomy Observatory13, University of British Columbia14
TL;DR: Pulsar J0348+0432 is only the second neutron star with a precisely determined mass of 2 M☉
Abstract: Many physically motivated extensions to general relativity (GR) predict significant deviations at energies present in massive neutron stars. We report the measurement of a 2.01 \(\pm \) 0.04 solar mass (M\(_\odot \)) pulsar in a 2.46-h orbit around a 0.172 \(\pm \) 0.003 M\(_\odot \) white dwarf. The high pulsar mass and the compact orbit make this system a sensitive laboratory of a previously untested strong-field gravity regime. Thus far, the observed orbital decay agrees with GR, supporting its validity even for the extreme conditions present in the system. The resulting constraints on deviations support the use of GR-based templates for ground-based gravitational wave detection experiments. Additionally, the system strengthens recent constraints on the properties of dense matter and provides novel insight to binary stellar astrophysics and pulsar recycling.
3,224 citations
"The Explosion of Helium Stars Evolv..." refers methods in this paper
...Abbott et al. (2018) concluded that the radii of the two merger components (whose masses are most likely between ∼1.1 M and ∼1.7 M ) are 11.9+1.4−1.4 km for EOSs that permit neutron stars with masses larger than 1.97 M as required by observations (Antoniadis et al. 2013)....
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TL;DR: In this article, the authors examined the current understanding of the lives and deaths of massive stars, with special attention to the relevant nuclear and stellar physics, and focused on their post-helium-burning evolution.
Abstract: amount of energy, a tiny fraction of which is sufficient to explode the star as a supernova. The authors examine our current understanding of the lives and deaths of massive stars, with special attention to the relevant nuclear and stellar physics. Emphasis is placed upon their post-helium-burning evolution. Current views regarding the supernova explosion mechanism are reviewed, and the hydrodynamics of supernova shock propagation and ‘‘fallback’’ is discussed. The calculated neutron star masses, supernova light curves, and spectra from these model stars are shown to be consistent with observations. During all phases, particular attention is paid to the nucleosynthesis of heavy elements. Such stars are capable of producing, with few exceptions, the isotopes between mass 16 and 88 as well as a large fraction of still heavier elements made by the r and p processes.
1,981 citations
"The Explosion of Helium Stars Evolv..." refers background or methods in this paper
...A popular ansatz for the explosion temperature, Texp, is given by (Woosley et al. 2002) 4 3 πr3faT 4exp ≈ Eexp (13) where Eexp is the energy of the explosion, usually taken to be the final kinetic energy, r is the radius, at the time the supernova shock begins to move outwards, of the zone that…...
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...For solar metallicity, they found a maximum black hole mass around 10 M when using presupernova models from Woosley et al. (2002), which had a larger mass loss rate than this present study (see their Figure 9)....
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...…and preliminary mass cut before fallback. h Fallback mass. i Emission time of 90% of the total radiated neutrino energy. j Total radiated neutrino energy (at 10 s after bounce, when typically ∼99% of the neutrino energy has been radiated). k Red supergiant progenitor from Woosley et al. (2002)....
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...As in Sukhbold et al. (2016), explosions were calculated using two different one-dimensional hydrodynamics codes, Prometheus-Hot Bubble (henceforth P-HOTB; Janka & Müller 1996; Kifonidis et al. 2003) and KEPLER (Weaver et al. 1978; Woosley et al. 2002)....
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...…stellar density is 5×1010 g cm−3. b Measured for SN 1987A calibration models when the central stellar density is 5×1010 g cm−3. c Red supergiant progenitor from the model series of Woosley et al. (2002). d M4 and µ4 measured roughly at core bounce, because pre-collapse data are not available. al....
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TL;DR: More than 70% of all massive stars will exchange mass with a companion, leading to a binary merger in one-third of the cases, greatly exceed previous estimates and imply that binary interaction dominates the evolution of massive stars, with implications for populations ofmassive stars and their supernovae.
Abstract: The presence of a nearby companion alters the evolution of massive stars in binary systems, leading to phenomena such as stellar mergers, x-ray binaries, and gamma-ray bursts. Unambiguous constraints on the fraction of massive stars affected by binary interaction were lacking. We simultaneously measured all relevant binary characteristics in a sample of Galactic massive O stars and quantified the frequency and nature of binary interactions. More than 70% of all massive stars will exchange mass with a companion, leading to a binary merger in one-third of the cases. These numbers greatly exceed previous estimates and imply that binary interaction dominates the evolution of massive stars, with implications for populations of massive stars and their supernovae.
1,779 citations
"The Explosion of Helium Stars Evolv..." refers background in this paper
...A large fraction, perhaps half or more of all stars massive enough to experience iron-core collapse, also interact with a close binary companion some time during their lives (Sana & Evans 2011; Sana et al. 2012)....
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