arXiv subjects

Adam Burrows

Publications and source records attributed to Adam Burrows.

At least 37 records · Page 2Linked to original sources

arXiv2024

A 3D Simulation of a Type II-P Supernova: from Core Bounce to Beyond Shock Breakout

In order to better connect core-collapse supernovae (CCSN) theory with its observational signatures, we have developed a simulation pipeline from the onset of core collapse to beyond shock breakout. Using this framework, we present a three-dimensional simulation study following the evolution from five seconds to over five days of a 17-M$_{\odot}$ progenitor that explodes with $\sim$10$^{51}$ erg of energy and $\sim$0.1 M$_{\odot}$ of $^{56}$Ni ejecta. The early explosion is highly asymmetric, expanding most prominently along the southern hemisphere. This early asymmetry is preserved to shock breakout, $\sim$1 day later. Breakout itself evinces strong angle-dependence, with as much a day delay in shock breakout by direction. The nickel ejecta closely tails the forward shock, with velocities at breakout as high as $\sim$7000 km s$^{-1}$. A delayed reverse shock forming at the H/He interface on hour timescales leads to the formation of Rayleigh-Taylor instabilities, fast-moving nickel bullets, and almost complete mixing of the metal core into the hydrogen envelope. For the first time, we illustrate the angle-dependent emergent broadband and bolometric light curves from simulations evolved in three-dimensions in entirety, continuing through hydrodynamic shock breakout a CCSN model of a massive stellar progenitor evolved with detailed, late-time neutrino microphysics and transport. Our case study of a single progenitor suggests that 3D simulations initiated with detailed neutrino heating can begin to generically produce the cornucopia of suggested asymmetries and features in CCSNe observations, while establishing the methodology to study this problem in breadth.

astro-ph.HE↗

arXiv2024

Jupiter Evolutionary Models Incorporating Stably Stratified Regions

We address the issue of which broad set of initial conditions for the planet Jupiter best matches the current presence of a ``fuzzy core" of heavy elements, while at the same time comporting with measured parameters such as its effective temperature, atmospheric helium abundance, radius, and atmospheric metallicity. Our focus is on the class of fuzzy cores that can survive convective mixing to the present day and on the unique challenges of an inhomogeneous Jupiter with stably-stratified regions now demanded by the \textit{Juno} gravity data. Hence, using the new code \texttt{APPLE}, we attempt to put a non-adiabatic Jupiter into an evolutionary context. This requires not only a mass density model, the major relevant byproduct of the \textit{Juno} data, but a thermal model that is subject to interior heat transport, a realistic atmospheric flux boundary, a helium rain algorithm, and the latest equation of state. The result is a good fit to most major thermal, compositional, and structural constraints that still preserve a fuzzy core and that should inform future more detailed models of the current Jupiter in the context of its evolution from birth.

astro-ph.EP↗

arXiv2024

Gravitational-Wave and Gravitational-Wave Memory Signatures of Core-Collapse Supernovae

In this paper, we calculate the energy, signal-to-noise ratio, detection range, and angular anisotropy of the matter, matter memory, and neutrino memory gravitational wave (GW) signatures of 21 three-dimensional initially non-rotating core-collapse supernova (CCSN) models carried to late times. We find that inferred energy, signal-to-noise ratio, and detection range are angle-dependent quantities, and that the spread of possible energy, signal-to-noise, and detection ranges across all viewing angles generally increases with progenitor mass. When examining the low-frequency matter memory and neutrino memory components of the signal, we find that the neutrino memory is the most detectable component of a CCSN GW signal, and that DECIGO is best-equipped to detect both matter memory and neutrino memory. Moreover, we find that the polarization angle between the $h_+$ and $h_{\times}$ strains serves as a unique identifier of matter and neutrino memory. Finally, we develop a galactic density- and stellar mass-weighted formalism to calculate the rate at which we can expect to detect CCSN GW signals with Advanced LIGO. When considering only the matter component of the signal, the aLIGO detection rate is around 24$\%$ of the total galactic supernova rate, but increases to 92$\%$ when incorporating the neutrino memory component. We find that all future detectors (ET, CE, DECIGO) will be able to detect CCSN GW signals from the entire galaxy, and for the higher-mass progenitors even into the local group of galaxies.

astro-ph.HE↗

arXiv2024

Insights into the Production of $^{44}$Ti and Nickel Isotopes in Core-Collapse Supernovae

We report nucleosynthetic results for both $^{44}$Ti and nickel isotopes for eighteen three-dimensional (3D) core-collapse supernova (CCSN) simulations extended to $\sim$20 seconds after bounce. We find that many of our long-term models are able to achieve $^{44}$Ti/$^{56}$Ni ratios similar to that observed in Cassiopeia A, and modern supernova models can synthesize up to $2\times10^{-4}M_\odot$ of $^{44}$Ti. Neutrino-driven winds and the fact that there can be simultaneous accretion and explosion in 3D models of core-collapse supernovae play central roles in its production. We conclude that the $^{44}$Ti underproduction problem in previous CCSN models is no longer an issue. In addition, we discuss the production of both $^{57}$Ni and stable nickel/iron ratios and compare our results to observations of SN1987A and the Crab.

astro-ph.HE↗

arXiv2024

Supernova Explosions of the Lowest-Mass Massive Star Progenitors

We here focus on the behavior of supernovae that technically explode in 1D (spherical symmetry). When simulated in 3D, however, the outcomes of representative progenitors of this class are quite different in almost all relevant quantities. In 3D, the explosion energies can be two to ten times higher, and there are correspondingly large differences in the $^{56}$Ni yields. These differences between the 3D and 1D simulations reflect in part the relative delay to explosion of the latter and in the former the presence of proto-neutron star convection that boosts the driving neutrino luminosities by as much as $\sim$50\% at later times. In addition, we find that the ejecta in 3D models are more neutron-rich, resulting in significant weak r-process and $^{48}$Ca yields. Furthermore, we find that in 3D the core is an interesting, though subdominant, source of acoustic power. In summary, we find that though a model might be found theoretically to explode in 1D, one must perform supernova simulations in 3D to capture most of the associated observables. The differences between 1D and 3D models are just too large to ignore.

astro-ph.HE↗

arXiv2024

APPLE: An Evolution Code for Modeling Giant Planets

We introduce APPLE, a novel planetary evolution code designed specifically for the study of giant exoplanet and Jovian planet evolution in the era of Galileo, Juno, and Cassini. With APPLE, state-of-the-art equations of state for hydrogen, helium, ice, and rock are integrated with advanced features to treat ice/rock cores and metals in the gaseous envelope; models for helium rain and hydrogen/helium immiscibility; detailed atmosphere boundary tables that also provide self-consistent albedos and spectra; and options to address envelope metal gradients and stably-stratified regions. Our hope is that these purpose-built features of APPLE will help catalyze the development of the next generation of giant exoplanet and Jovian planet evolutionary models.

astro-ph.EP↗

arXiv2024

The Lunar Gravitational-wave Antenna: Mission Studies and Science Case

The Lunar Gravitational-wave Antenna (LGWA) is a proposed array of next-generation inertial sensors to monitor the response of the Moon to gravitational waves (GWs). Given the size of the Moon and the expected noise produced by the lunar seismic background, the LGWA would be able to observe GWs from about 1 mHz to 1 Hz. This would make the LGWA the missing link between space-borne detectors like LISA with peak sensitivities around a few millihertz and proposed future terrestrial detectors like Einstein Telescope or Cosmic Explorer. In this article, we provide a first comprehensive analysis of the LGWA science case including its multi-messenger aspects and lunar science with LGWA data. We also describe the scientific analyses of the Moon required to plan the LGWA mission.

gr-qc↗

arXiv2024

Physical Correlations and Predictions Emerging from Modern Core-Collapse Supernova Theory

In this paper, we derive correlations between core-collapse supernova observables and progenitor core structures that emerge from our suite of twenty state-of-the-art 3D core-collapse supernova simulations carried to late times. This is the largest such collection of 3D supernova models ever generated and allows one to witness and derive testable patterns that might otherwise be obscured when studying one or a few models in isolation. From this panoramic perspective, we have discovered correlations between explosion energy, neutron star gravitational birth masses, $^{56}$Ni and $\alpha$-rich freeze-out yields, and pulsar kicks and theoretically important correlations with the compactness parameter of progenitor structure. We find a correlation between explosion energy and progenitor mantle binding energy, suggesting that such explosions are self-regulating. We also find a testable correlation between explosion energy and measures of explosion asymmetry, such as the ejecta energy and mass dipoles. While the correlations between two observables are roughly independent of the progenitor ZAMS mass, the many correlations we derive with compactness can not unambiguously be tied to a particular progenitor ZAMS mass. This relationship depends upon the compactness/ZAMS mass mapping associated with the massive star progenitor models employed. Therefore, our derived correlations between compactness and observables may be more robust than with ZAMS mass, but can nevertheless be used in the future once massive star modeling has converged.

astro-ph.HE↗

arXiv2024

Equations of State, Thermodynamics, and Miscibility Curves for Jovian Planet and Giant Exoplanet Evolutionary Models

The equation of state of hydrogen-helium (H-He) mixtures plays a vital role in the evolution and structure of gas giant planets and exoplanets. Recent equations of state that account for hydrogen-helium interactions, coupled with hydrogen-helium immiscibility curves, can now produce more physical evolutionary models, such as accounting for helium rain with greater fidelity than in the past. In this work, we present a set of tools for planetary evolution\footnote{All tables of thermodynamic quantities and derivatives are available at \url{https://github.com/Rob685/hhe_eos_misc}, along with a unified Python interface. Tutorials demonstrating the interface are also available in the repository.} that provides a Python interface for existing tables of useful thermodynamic quantities, state-of-the-art H-He equations of state, and pressure-dependent H-He immiscibility curves. In particular, for a collection of independent variable choices, we provide scripts to calculate the variety of thermodynamic derivatives used to model convection and energy transport. These include the chemical potential derived from the internal energy, which is a modeling necessity in the presence of composition gradients when entropy is the other primary variable. Finally, an entropy-based convection formalism is presented and fully described that highlights the physical differences between adiabatic and isentropic interior models. This centralized resource is meant to facilitate both giant planet structural and evolutionary modeling and the entry of new research groups into the field of giant planet modeling.

astro-ph.EP↗

arXiv2024

A JWST Survey of the Supernova Remnant Cassiopeia A

We present initial results from a JWST survey of the youngest Galactic core-collapse supernova remnant Cassiopeia A (Cas A), made up of NIRCam and MIRI imaging mosaics that map emission from the main shell, interior, and surrounding circumstellar/interstellar material (CSM/ISM). We also present four exploratory positions of MIRI/MRS IFU spectroscopy that sample ejecta, CSM, and associated dust from representative shocked and unshocked regions. Surprising discoveries include: 1) a web-like network of unshocked ejecta filaments resolved to 0.01 pc scales exhibiting an overall morphology consistent with turbulent mixing of cool, low-entropy matter from the progenitor's oxygen layer with hot, high-entropy matter heated by neutrino interactions and radioactivity, 2) a thick sheet of dust-dominated emission from shocked CSM seen in projection toward the remnant's interior pockmarked with small (approximately one arcsecond) round holes formed by knots of high-velocity ejecta that have pierced through the CSM and driven expanding tangential shocks, 3) dozens of light echoes with angular sizes between 0.1 arcsecond to 1 arcminute reflecting previously unseen fine-scale structure in the ISM. NIRCam observations place new upper limits on infrared emission from the neutron star in Cas A's center and tightly constrain scenarios involving a possible fallback disk. These JWST survey data and initial findings help address unresolved questions about massive star explosions that have broad implications for the formation and evolution of stellar populations, the metal and dust enrichment of galaxies, and the origin of compact remnant objects.

astro-ph.HE↗

arXiv2023

A Theory for Neutron Star and Black Hole Kicks and Induced Spins

Using twenty long-term 3D core-collapse supernova simulations, we find that lower compactness progenitors that explode quasi-spherically due to the short delay to explosion experience smaller neutron star recoil kicks in the $\sim$100$-$200 km s$^{-1}$ range, while higher compactness progenitors that explode later and more aspherically leave neutron stars with kicks in the $\sim$300$-$1000 km s$^{-1}$ range. In addition, we find that these two classes are correlated with the gravitational mass of the neutron star. This correlation suggests that the survival of binary neutron star systems may in part be due to their lower kick speeds. We also find a correlation of the kick with both the mass dipole of the ejecta and the explosion energy. Furthermore, one channel of black hole birth leaves masses of $\sim$10 $M_{\odot}$, is not accompanied by a neutrino-driven explosion, and experiences small kicks. A second is through a vigorous explosion that leaves behind a black hole with a mass of $\sim$3.0 $M_{\odot}$ kicked to high speeds. We find that the induced spins of nascent neutron stars range from seconds to $\sim$10 milliseconds, {but do not yet see a significant spin/kick correlation for pulsars.} We suggest that if an initial spin biases the explosion direction, a spin/kick correlation {would be} a common byproduct of the neutrino mechanism of core-collapse supernovae. Finally, the induced spin in explosive black hole formation is likely large and in the collapsar range. This new 3D model suite provides a greatly expanded perspective and appears to explain some observed pulsar properties by default.

astro-ph.HE↗

arXiv2023

Nucleosynthetic Analysis of Three-Dimensional Core-Collapse Supernova Simulations

We study in detail the ejecta conditions and theoretical nucleosynthetic results for 18 three-dimensional core-collapse supernova (CCSN) simulations done by F{\sc ornax}. {Most simulations are carried out to at least 3 seconds after bounce, which allows us to follow their longer-term behaviors.} We find that multi-dimensional effects introduce many complexities into ejecta conditions. We see stochastic electron fraction evolution, complex peak temperature distributions and histories, and long-tail distributions of the time spent within nucleosynthetic temperature ranges. These all lead to substantial variation in CCSN nucleosynthetic yields and differences with 1D results. We discuss the production of lighter $\alpha$-nuclei, radioactive isotopes, heavier elements, and a few isotopes of special interest. Comparing pre-CCSN and CCSN contributions, we find that a significant fraction of elements between roughly Si and Ge are generically produced in CCSNe. We find that $^{44}$Ti exhibits an extended production timescale compared to $^{56}$Ni, which may explain its different distribution and higher than previously predicted abundances in supernova remnants such as Cas A and SN1987A. We also discuss the morphology of the ejected elements. This study highlights the high-level diversity of ejecta conditions and nucleosynthetic results in 3D CCSN simulations and emphasizes the need for additional long-term {($\sim$10 seconds)} 3D simulations to properly address such complexities.

astro-ph.HE↗

arXiv2023

Jupiter Atmospheric Models and Outer Boundary Conditions for Giant Planet Evolutionary Calculations

We present updated atmospheric tables suitable for calculating the post-formation evolution and cooling of Jupiter and Jupiter-like exoplanets. These tables are generated using a 1D radiative transfer modeling code that incorporates the latest opacities and realistic prescriptions for stellar irradiation and ammonia clouds. To ensure the accuracy of our model parameters, we calibrate them against the measured temperature structure and geometric albedo spectrum of Jupiter, its effective temperature, and its inferred internal temperature. As a test case, we calculate the cooling history of Jupiter using an adiabatic and homogeneous interior and compare with extant models now used to evolve Jupiter and the giant planets. We find that our model reasonably matches Jupiter after evolving a hot-start initial condition to the present age of the solar system, with a discrepancy in brightness temperature/radius within two per cent. Our algorithm allows us to customize for different cloud, irradiation, and metallicity parameters. This class of boundary conditions can be used to study the evolution of solar-system giant planets and exoplanets with more complicated interior structures and non-adiabatic, inhomogeneous internal profiles.

astro-ph.EP↗

arXiv2023

Black-Hole Formation Accompanied by the Supernova Explosion of a 40-M$_{\odot}$ Progenitor Star

We have simulated the collapse and evolution of the core of a solar-metallicity 40-M$_{\odot}$ star and find that it explodes vigorously by the neutrino mechanism. This despite its very high "compactness". Within $\sim$1.5 seconds of explosion, a black hole forms. The explosion is very asymmetrical and has a total explosion energy of $\sim$1.6$\times$10$^{51}$ ergs. At black hole formation, its baryon mass is $\sim$2.434 M$_{\odot}$ and gravitational mass is 2.286 M$_{\odot}$. Seven seconds after black hole formation an additional $\sim$0.2 M$_{\odot}$ is accreted, leaving a black hole baryon mass of $\sim$2.63 M$_{\odot}$. A disk forms around the proto-neutron star, from which a pair of neutrino-driven jets emanates. These jets accelerate some of the matter up to speeds of $\sim$45,000 km s$^{-1}$ and contain matter with entropies of $\sim$50. The large spatial asymmetry in the explosion results in a residual black hole recoil speed of $\sim$1000 km s$^{-1}$. This novel black-hole formation channel now joins the other black-hole formation channel between $\sim$12 and $\sim$15 M$_{\odot}$ discovered previously and implies that the black-hole/neutron-star birth ratio for solar-metallicity stars could be $\sim$20\%. However, one channel leaves black holes in perhaps the $\sim$5-15 M$_{\odot}$ range with low kick speeds, while the other leaves black holes in perhaps the $\sim$2.5-3.0 M$_{\odot}$ mass range with high kick speeds. However, even $\sim$8.8 seconds after core bounce the newly-formed black hole is still accreting at a rate of $\sim$2$\times$10$^{-2}$ M$_{\odot}$ s$^{-1}$ and whether the black hole eventually achieves a significantly larger mass over time is yet to be determined.

astro-ph.SR↗

arXiv2023

Neutrino Signatures of One Hundred 2D Axisymmetric Core-Collapse Supernova Simulations

We present in this paper a public data release of an unprecedentedly-large set of core-collapse supernova (CCSN) neutrino emission models, comprising one hundred detailed 2D-axisymmetric radiation-hydrodynamic simulations evolved out to as late as ~5 seconds post-bounce and spanning a extensive range of massive-star progenitors. The motivation for this paper is to provide a physically and numerically uniform benchmark dataset to the broader neutrino detection community to help it characterize and optimize subsurface facilities for what is likely to be a once-in-a-lifetime galactic supernova burst event. With this release we hope to 1) help the international experiment and modeling communities more efficiently optimize the retrieval of physical information about the next galactic core-collapse supernova, 2) facilitate the better understanding of core-collapse theory and modeling among interested experimentalists, and 3) help further integrate the broader supernova neutrino community.

astro-ph.HE↗

arXiv2023

Neutrino-Driven Winds in Three-Dimensional Core-Collapse Supernova Simulations

In this paper, we analyze the neutrino-driven winds that emerge in twelve unprecedentedly long-duration 3D core-collapse supernova simulations done using the code Fornax. The twelve models cover progenitors with ZAMS mass between 9 and 60 solar masses. In all our models, we see transonic outflows that are at least two times as fast as the surrounding ejecta and that originate generically from a PNS surface atmosphere that is turbulent and rotating. We find that winds are common features of 3D simulations, even if there is anisotropic early fallback. We find that the basic dynamical properties of 3D winds behave qualitatively similarly to those inferred in the past using simpler 1D models, but that the shape of the emergent wind can be deformed, very aspherical, and channeled by its environment. The thermal properties of winds for less massive progenitors very approximately recapitulate the 1D stationary solutions, while for more massive progenitors they deviate significantly due to aspherical fallback. The $Y_e$ temporal evolution in winds is stochastic, and there can be some neutron-rich phases. Though no strong r-process is seen in any model, a weak r-process can be produced and isotopes up to $^{90}$Zr are synthesized in some models. Finally, we find that there is at most a few percent of a solar mass in the integrated wind component, while the energy carried by the wind itself can be as much as 10-20% of the total explosion energy.

astro-ph.SR↗

arXiv2023

Measuring the properties of $f-$mode oscillations of a protoneutron star by third generation gravitational-wave detectors

Core-collapse supernovae are among the astrophysical sources of gravitational waves that could be detected by third-generation gravitational-wave detectors. Here, we analyze the gravitational-wave strain signals from two- and three-dimensional simulations of core-collapse supernovae generated using the code F{\sc{ornax}}. A subset of the two-dimensional simulations has non-zero core rotation at the core bounce. A dominant source of time changing quadrupole moment is the $l=2$ fundamental mode ($f-$ mode) oscillation of the proto-neutron star. From the time-frequency spectrogram of the gravitational-wave strain we see that, starting $\sim 400$ ms after the core bounce, most of the power lies within a narrow track that represents the frequency evolution of the $f-$mode oscillations. The $f-$mode frequencies obtained from linear perturbation analysis of the angle-averaged profile of the protoneutron star corroborate what we observe in the spectrograms of the gravitational-wave signal. We explore the measurability of the $f-$mode frequency evolution of protoneutron star for a supernova signal observed in the third-generation gravitational-wave detectors. Measurement of the frequency evolution can reveal information about the masses, radii, and densities of the proto-neutron stars. We find that if the third generation detectors observe a supernova within 10 kpc, we can measure these frequencies to within $\sim$90\% accuracy. We can also measure the energy emitted in the fundamental $f-$mode using the spectrogram data of the strain signal. We find that the energy in the $f-$mode can be measured to within 20\% error for signals observed by Cosmic Explorer using simulations with successful explosion, assuming source distances within 10 kpc.

astro-ph.IM↗

arXiv2023

Self-consistent Models of Y Dwarf Atmospheres with Water Clouds and Disequilibrium Chemistry

Y dwarfs are the coolest spectral class of brown dwarf. They have effective temperatures less than 500 K, with the coolest detection as low as ~250 K. Their spectra are shaped predominantly by gaseous water, methane, and ammonia. At the warmer end of the Y dwarf temperature range, spectral signatures of disequilibrium carbon monoxide have been observed. Cooler Y dwarfs could host water clouds in their atmospheres. Since they make up the low-mass tail of the star formation process, and are a valuable analogue to the atmospheres of giant gaseous exoplanets in a temperature range that is difficult to observe, understanding Y dwarf atmospheric compositions and processes will both deepen our understanding of planet and star formation, and provide a stepping stone towards characterizing cool exoplanets. JWST spectral observations are anticipated to provide an unprecedented level of detail for these objects, and yet published self-consistent model grids do not accurately replicate even the existing HST and ground-based observations. In this work, we present a new suite of 1-d radiative-convective equilibrium models to aid in the characterization of Y dwarf atmospheres and spectra. We compute clear, cloudy, equilibrium-chemistry and disequilibrium-chemistry models, providing a comprehensive suite of models in support of the impending JWST era of panchromatic Y dwarf characterization. Comparing these models against current observations, we find that disequilibrium CH4-CO and NH3-N2 chemistry and the presence of water clouds can bring models and observations into better, though still not complete, agreement.

astro-ph.EP↗