Publications (146)
Effective Helium Burning Rates and the Production of the Neutrino Nuclei
Sam M. Austin, Christopher West, Alexander Heger
Effective values for the key helium burning reaction rates, triple-alpha and 12C(alpha,gamma)16O, are obtained by adjusting their strengths so as to obtain the best match with the…
Evolution of wide O star binaries through their LBV stage. Population synthesis with mass-ejection-driven orbital evolution
Xiao-Tian Xu, Philipp Podsiadlowski, Norbert Langer +6
Context. Long-period Wolf-Rayet (WR) star binaries produced by mass transfer are predicted to be abundant, but are observationally rare. This yields constraints on the evolution of…
The Impact of Initial Composition on Massive Star Evolution and Nucleosynthesis
Christopher West, Alexander Heger, Benoit Cote +2
We study the sensitivity of presupernova evolution and supernova nucleosynthesis yields of massive stars to variations of the initial composition. We use the solar abundances from…
GRBs and Relativistic Transients in the 2040s
Nikhil Sarin, Andrew Levan, Nial Tanvir +9
Relativistic transients such as gamma-ray bursts (GRBs), jetted tidal disruption events, luminous fast blue optical transients, and fast X-ray transients, represent the brightest e…
Production of 26Al, 44Ti and 60Fe in Supernovae-sensitivity to the helium burning rates
Clarisse Tur, Alexander Heger, Sam M. Austin
We have studied the sensitivity of supernova production of the gamma emitting nuclei 26Al, 44Ti and 60Fe to variations of the rates of the triple alpha and 12C(alpha, gamma) reacti…
Detecting Primordial Stars
Evan Scannapieco, Andrea Ferrara, Alexander Heger +3
We study the detectability of primordial metal-free stars. Cosmological enrichment is a local process that takes place over an extended redshift range. While the duration of this t…
Dependence of S-Process Nucleosynthesis in Massive Stars on Triple-Alpha and 12C(a,g)16O Reaction Rate Uncertainties
Clarisse Tur, Alexander Heger, Sam M. Austin
We have studied the sensitivity of s-process nucleosynthesis in massive stars to +/- 2 sigma variations in the rates of the triple alpha and 12C(a,g)16O reactions. We simulated the…
On the Detection of Supermassive Primordial Stars
Marco Surace, Daniel J. Whalen, Tilman Hartwig +6
The collapse of supermassive primordial stars in hot, atomically-cooled halos may have given birth to the first quasars at 15 - 20. Recent numerical simulations of these r…
On the Evolution of Supermassive Primordial Stars in Cosmological Flows
Tyrone E. Woods, Samuel Patrick, Jacob S. Elford +2
Primordial supermassive stars (SMSs) formed in atomic-cooling halos at z ~ 15 - 20 are leading candidates for the seeds of the first quasars. Past numerical studies of the evolutio…
Multidimensional Simulations of Thermonuclear Supernovae from the First Stars
Ke-Jung Chen, Alexander Heger, Ann Almgren
Theoretical models suggest that the first stars in the universe could have been very massive, with typical masses 100 \Msun. Many of them might have died as energetic the…
X-Ray and Gamma-Ray Emission From Core-collapse Supernovae: Comparison of Three-dimensional Neutrino-driven Explosions With SN 1987A
Dennis Alp, Josefin Larsson, Keiichi Maeda +7
During the first few hundred days after the explosion, core-collapse supernovae (SNe) emit down-scattered X-rays and gamma-rays originating from radioactive line emissions, primari…
Mass and Metallicity Requirement in Stellar Models for Galactic Chemical Evolution Applications
Benoit Côté, Christopher West, Alexander Heger +5
We used a one-zone chemical evolution model to address the question of how many masses and metallicities are required in grids of massive stellar models in order to ensure reliable…
Can direct collapse black holes launch gamma-ray bursts and grow to supermassive black holes?
Tatsuya Matsumoto, Daisuke Nakauchi, Kunihito Ioka +2
The existence of black holes (BHs) of mass ~ 10^{9} M_sun at z > 6 is a big puzzle in astrophysics because even optimistic estimates of the accretion time are insufficient for stel…
Conservative Initial Mapping For Multidimensional Simulations of Stellar Explosions
Ke-Jung Chen, Alexander Heger, Ann Almgren
Mapping one-dimensional stellar profiles onto multidimensional grids as initial conditions for hydrodynamics calculations can lead to numerical artifacts, one of the most severe of…
Neutron star kicks plus rockets as a mechanism for forming wide low-eccentricity neutron star binaries
Ryosuke Hirai, Philipp Podsiadlowski, Alexander Heger +1
Recent neutron star surface observations corroborate a long-standing theory that neutron stars may be accelerated over extended periods after their birth. We analyze how these prol…
New Neutron-Capture Site in Massive Pop III and Pop II Stars as a Source for Heavy Elements in the Early Galaxy
Projjwal Banerjee, Yong-Zhong Qian, Alexander Heger
We propose a new neutron-capture site in early metal-poor and metal-free stars of -- that results from proton ingestion in the He shell during late…
On the origin of nitrogen at low metallicity
Arpita Roy, Michael A. Dopita, Mark R. Krumholz +3
Understanding the evolution of the N/O ratio in the interstellar medium (ISM) of galaxies is essential if we are to complete our picture of the chemical evolution of galaxies at hi…
The Role of the Hadron-Quark Phase Transition in Core-Collapse Supernovae
Pia Jakobus, Bernhard Mueller, Alexander Heger +3
The hadron-quark phase transition in quantum chromodyanmics has been suggested as an alternative explosion mechanism for core-collapse supernovae. We study the impact of three diff…
Are most detected tidal disruption events partial?
Megha Sharma, Daniel J. Price, Alexander Heger +1
During a tidal disruption event (TDE), a star loses mass due to the tidal gravitational forces of the black hole. In a partial tidal disruption event, a stellar remnant is left beh…
Binary Merger Progenitors for Gamma-Ray Bursts and Hypernovae
Chris L. Fryer, Alexander Heger
The collapsar model, the now leading model for the engine behind gamma-ray bursts and hypernovae, requires that a star collapses to form a black hole surrounded by an accretion dis…
Pair Instability Supernovae of Very Massive Population III Stars
Ke-Jung Chen, Alexander Heger, Stan Woosley +2
Numerical studies of primordial star formation suggest that the first stars in the universe may have been very massive. Stellar models indicate that non-rotating Population III sta…
Numerical approaches for multidimensional simulations of stellar explosions
Ke-Jung Chen, Alexander Heger, Ann Almgren
We introduce numerical algorithms for initializing multidimensional simulations of stellar explosions with 1D stellar evolution models. The initial mapping from 1D profiles onto mu…
Large-Scale Mixing in a Violent Oxygen-Neon Shell Merger Prior to a Core-Collapse Supernova
Naveen Yadav, Bernhard Müller, Hans Thomas Janka +2
We present a seven-minute long -3D simulation of a shell merger event in a non-rotating supernova progenitor before the onset of gravitational collapse. The…
Detection of Millihertz Quasi-Periodic Oscillations in the X-Ray Binary 1RXS J180408.9342058
Kaho Tse, Duncan K. Galloway, Yi Chou +2
Millihertz quasi-periodic oscillations (mHz QPOs) observed in neutron-star low-mass X-ray binaries (NS LMXBs) are generally explained as marginally stable thermonuclear burning on…
Reducing Uncertainties in the Production of the Gamma Emitting Nuclei 26Al, 44Ti, and 60Fe in Core Collapse Supernovae by Using Effective Helium Burning Rates
Sam Austin, Christopher West, Alexander Heger
We have used effective reaction rates (ERR) for the helium burning reactions to predict the yield of the gamma-emitting nuclei 26Al, 44Ti, and 60Fe in core col- lapse supernovae. T…
Which Massive stars are Gamma-Ray Burst Progenitors?
Jelena Petrovic, Norbert Langer, Sung-Chul Yoon +1
The collapsar model for gamma-ray bursts requires three essential ingredients: a massive core, removal of the hydrogen envelope, and enough angular momentum in the core. We study c…
Rapidly Rotating Massive Pop III stars: A Solution for High Carbon Enrichment in CEMP-no Stars
Jeena S K, Projjwal Banerjee, Gen Chiaki +1
Very metal-poor stars that have and that are enhanced in C relative to Fe () but have no enhancement of heavy elements ($[\text…
Are Models for Core-Collapse Supernova Progenitors Consistent with the Properties of Supernova Remnants?
Daniel J. Patnaude, Shiu-Hang Lee, Patrick O. Slane +4
The recent discovery that the Fe-K line luminosities and energy centroids observed in nearby SNRs are a strong discriminant of both progenitor type and circumstellar environment ha…
The chemical signature of jet-driven hypernovae
J. J. Grimmett, Bernhard Müller, Alexander Heger +2
Hypernovae powered by magnetic jets launched from the surface of rapidly rotating millisecond magnetars are one of the leading models to explain broad-lined Type Ic supernovae (SNe…
Near-Earth Supernova Explosions: Evidence, Implications, and Opportunities
Brian D. Fields, John R. Ellis, Walter R. Binns +36
There is now solid experimental evidence of at least one supernova explosion within 100 pc of Earth within the last few million years, from measurements of the short-lived isotope…
Light Curves of Type IIP Supernovae from Neutrino-driven Explosions of Red Supergiants Obtained by a Semi-analytic Approach
Shuai Zha, Bernhard Müller, Amy Weir +1
Type IIP supernovae (SNe IIP) mark the explosive death of red supergiants (RSGs), evolved massive stars with an extended hydrogen envelope. They are the most common supernova type…
On the Rotation of Supermassive Stars
Lionel Haemmerlé, Tyrone E. Woods, Ralf S. Klessen +2
Supermassive stars born from pristine gas in atomically-cooled haloes are thought to be the progenitors of supermassive black holes at high redshifts. However, the way they accrete…
Production of 26Al, 44Ti, and 60Fe in Core-Collapse Supernovae: Sensitivity to the Rates of the Triple Alpha and 12C(a,g)16O Reactions
Clarisse Tur, Alexander Heger, Sam M. Austin
We have studied the sensitivity to variations in the the triple alpha and 12C(a,g)16O reaction rates of the production of 26Al, 44Ti, and 60Fe in core-collapse supernovae. We used…
On Monolithic Supermassive Stars
Tyrone E. Woods, Alexander Heger, Lionel Haemmerlé
Supermassive stars have been proposed as the progenitors of the massive () quasars observed at . Prospects for directly detecting supermassive…
The Biggest Explosions in the Universe. II
Daniel J. Whalen, Jarrett L. Johnson, Joseph Smidt +3
One of the leading contenders for the origin of supermassive black holes at 7 is catastrophic baryon collapse in atomically-cooled halos at 15. In this scenari…
Finding the First Cosmic Explosions I: Pair-Instability Supernovae
Daniel J. Whalen, Wesley Even, Lucille H. Frey +9
The first stars are the key to the formation of primitive galaxies, early cosmological reionization and chemical enrichment, and the origin of supermassive black holes. Unfortunate…
The Radioactive Nuclei Al and Fe in the Cosmos and in the Solar System
Roland Diehl, Maria Lugaro, Alexander Heger +15
The cosmic evolution of the chemical elements from the Big Bang to the present time is driven by nuclear fusion reactions inside stars and stellar explosions. A cycle of matter rec…
Simulating X-ray bursts during a transient accretion event
Zac Johnston, Alexander Heger, Duncan K. Galloway
Modelling of thermonuclear X-ray bursts on accreting neutron stars has to date focused on stable accretion rates. However, bursts are also observed during episodes of transient acc…
First Stars III Conference Summary
Brian W. O'Shea, Christopher F. McKee, Alexander Heger +1
The understanding of the formation, life, and death of Population III stars, as well as the impact that these objects had on later generations of structure formation, is one of the…
Multi-epoch X-ray burst modelling: MCMC with large grids of 1D simulations
Zac Johnston, Alexander Heger, Duncan K. Galloway
Type-I X-ray bursts are recurring thermonuclear explosions on the surface of accreting neutron stars. Matching observed bursts to computational models can help to constrain system…
The influence of accretion rate and metallicity on thermonuclear bursts: predictions from KEPLER models
Nathanael Lampe, Alexander Heger, Duncan K. Galloway
Using the KEPLER hydrodynamics code, 464 models of thermonuclear X-ray bursters were performed across a range of accretion rates and compositions. We present the library of simulat…
Millihertz Quasi-Periodic Oscillations from Marginally Stable Nuclear Burning on an Accreting Neutron Star
Alexander Heger, Andrew Cumming, Stanford E. Woosley
We investigate marginally stable nuclear burning on the surface of accreting neutron stars as an explanation for the mHz quasi-periodic oscillations (QPOs) observed from three low…
The Chemical Evolution of Iron-Peak Elements with Hypernovae
J. J. Grimmett, Amanda I. Karakas, Alexander Heger +2
We calculate the mean evolution of the iron-peak abundance ratios [(Cr,Mn,Co,Zn)/Fe] in the Galaxy, using modern supernova and hypernova chemical yields and a Galactic Chemical Evo…
The quest for blue supergiants: binary merger models for the evolution of the progenitor of SN 1987A
Athira Menon, Alexander Heger
We present the results of a detailed, systematic stellar evolution study of binary mergers for blue supergiant (BSG) progenitors of Type II supernovae. In particular, these are the…
Production of Lithium in Primordial Supernovae
Alexander Heger, Stan Woosley
The first generation of stars is quite unique. The absence of metals likely affects their formation, with current models suggesting a much more top-heavy initial mass fraction than…
Fallback accretion powered supernova light curves based on a neutrino-driven explosion simulation of a 40 Msun star
Takashi J. Moriya, Bernhard Muller, Conrad Chan +2
We present synthetic light curves of fallback-powered supernovae based on a neutrino-driven explosion of a 40 Msun zero-metallicity star with significant fallback accretion onto a…
The Detectability of Pair-Production Supernovae at z < 6
Evan Scannapieco, Piero Madau, Stan Woosley +2
Nonrotating, zero metallicity stars with initial masses 140 < M < 260 solar masses are expected to end their lives as pair-production supernovae (PPSNe), in which an electron-posit…
Discovery of millihertz Quasi-Periodic Oscillations in the Low Mass X-Ray Binary XTE J1701462 from a Search of the RXTE Legacy data set
Kaho Tse, Duncan K. Galloway, Alexander Heger
We report the detection of millihertz quasi-periodic oscillations ( QPOs) from the low-mass X-ray binary XTE J1701462. The discovery came from a search of the lega…
The Last Minutes of Oxygen Shell Burning in a Massive Star
Bernhard Müller, Maxime Viallet, Alexander Heger +1
We present the first 3D simulation of the last minutes of oxygen shell burning in an 18 solar mass supernova progenitor up to the onset of core collapse. A moving inner boundary is…
Black hole formation and fallback during the supernova explosion of a star
Conrad Chan, Bernhard Müller, Alexander Heger +2
Fallback in core-collapse supernovae is considered a major ingredient for explaining abundance anomalies in metal-poor stars and the natal kicks and spins of black holes (BHs). We…
Pulsational Analysis of the Cores of Massive Stars and its Relevance to Pulsar Kicks
Jeremiah Murphy, Adam Burrows, Alexander Heger
The mechanism responsible for the natal kicks of neutron stars continues to be a challenging problem. Indeed, many mechanisms have been suggested, and one hydrodynamic mechanism ma…
Two-Dimensional Simulations of Pulsational Pair-Instability Supernovae
Ke-Jung Chen, Stan Woosley, Alexander Heger +2
Massive stars that end their lives with helium cores in the range of 35 to 65 Msun are known to produce repeated thermonuclear outbursts due to a recurring pair-instability. In som…
1000-10,000 M Primordial Stars Created the Nitrogen Excess in GS 3073 at
Devesh Nandal, Daniel J. Whalen, Muhammad A. Latif +1
The advent of the James Webb Space Telescope has revealed a wealth of new galaxies just a few hundred Myr after the Big Bang. Some of these galaxies exhibit unusual N/O ratios that…
The minimum neutron star mass in neutrino-driven supernova explosions
Bernhard Müller, Alexander Heger, Jade Powell
Supernova theory has struggled to explain the lightest known neutron star candidate with an accurate mass determination, the companion in the eccentric comp…
Pair-Instability Supernovae in the Local Universe
Daniel J. Whalen, Wesley Even, Joseph Smidt +7
The discovery of 150 - 300 M stars in the Local Group and pair-instability supernova candidates at low redshifts has excited interest in this exotic explosion mechanism.…
Observational signatures of the surviving donor star in the double detonation model of Type Ia supernovae
Zheng-Wei Liu, Friedrich K. Roepke, Yaotian Zeng +1
The sub-Chandrasekhar mass double-detonation (DDet) scenario is a contemporary model for SNe Ia. The donor star in the DDet scenario is expected to survive the explosion and to be…
Titans of the Early Universe: The Prato Statement on the Origin of the First Supermassive Black Holes
Tyrone E. Woods, Bhaskar Agarwal, Volker Bromm +30
In recent years, the discovery of massive quasars at z~7 has provided a striking challenge to our understanding of the origin and growth of supermassive black holes in the early Un…
Finding the First Cosmic Explosions II: Core-Collapse Supernovae
Daniel J. Whalen, Candace C. Joggerst, Chris L. Fryer +3
Understanding the properties of Pop III stars is prerequisite to elucidating the nature of primeval galaxies, the chemical enrichment and reionization of the early IGM, and the ori…
Models of Type I X-ray Bursts from GS 1826-24: A Probe of rp-Process Hydrogen Burning
Alexander Heger, Andrew Cumming, Duncan K. Galloway +1
The X-ray burster GS 1826-24 shows extremely regular Type I X-ray bursts whose energetics and recurrence times agree well with thermonuclear ignition models. We present calculation…
A Minimum Dilution Scenario for Supernovae and Consequences for Extremely Metal-Poor Stars
Mattis Magg, Thomas Nordlander, Simon C. O. Glover +6
To date no metal-free stars have been identified by direct observations. The most common method of constraining their properties is searching the spectra of the most metal-poor sta…
Fast evolving pair-instability supernova models: evolution, explosion, light curves
Alexandra Kozyreva, Matthew Gilmer, Raphael Hirschi +11
With an increasing number of superluminous supernovae (SLSNe) discovered the question of their origin remains open and causes heated debates in the supernova community. Currently,…
Gravitational Waves from a Core g-Mode in Supernovae as Probes of the High-Density Equation of State
Pia Jakobus, Bernhard Müller, Alexander Heger +5
Using relativistic supernova simulations of massive progenitor stars with a quark-hadron equation of state (EoS) and a purely hadronic EoS, we identify a distinctive feature in the…
Long-term evolution of post-explosion Helium-star Companions of Type Iax Supernovae
Yaotian Zeng, Zheng-Wei Liu, Alexander Heger +3
Supernovae of Type Iax (SNe Iax) are an accepted faint subclass of hydrogen-free supernovae. Their origin, the nature of the progenitor systems, however, is an open question. Recen…
Seeing the First Supernovae at the Edge of the Universe with JWST
Daniel J. Whalen, Chris L. Fryer, Daniel E. Holz +5
The first stars ended the cosmic Dark Ages and created the first heavy elements necessary for the formation of planets and life. The properties of these stars remain uncertain, and…
Nucleosynthesis and Evolution of Massive Metal-Free Stars
Alexander Heger, S. E. Woosley
The evolution and explosion of metal-free stars with masses 10--100 solar masses are followed, and their nucleosynthetic yields, light curves, and remnant masses determined. When t…
The Pair-Instability Mass Gap for Black Holes
S. E. Woosley, Alexander Heger
Stellar evolution theory predicts a "gap" in the black hole birth function caused by the pair instability. Presupernova stars that have a core mass below some limiting value, Mlo,…
Finding the First Cosmic Explosions. III. Pulsational Pair-Instability Supernovae
Daniel J. Whalen, Joseph Smidt, Wesley Even +4
Population III supernovae have been the focus of growing attention because of their potential to directly probe the properties of the first stars, particularly the most energetic e…
Low-energy Population III supernovae and the origin of extremely metal-poor stars
Ke-Jung Chen, Alexander Heger, Daniel J. Whalen +3
Some ancient, dim, metal-poor stars may have formed in the ashes of the first supernovae (SNe). If their chemical abundances can be reconciled with the elemental yields of specific…
The Deaths of Very Massive Stars
S. E. Woosley, Alexander Heger
The theory underlying the evolution and death of stars heavier than 10 Msun on the main sequence is reviewed with an emphasis upon stars much heavier than 30 Msun. These are stars…
Stellar origin of the 182Hf cosmochronometer and the presolar history of solar system matter
Maria Lugaro, Alexander Heger, Dean Osrin +7
Among the short-lived radioactive nuclei inferred to be present in the early solar system via meteoritic analyses, there are several heavier than iron whose stellar origin has been…
Black holes as the end state of stellar evolution: Theory and simulations
Alexander Heger, Bernhard Müller, Ilya Mandel
The collapse of massive stars is one of the most-studied paths to black hole formation. In this chapter, we review black hole formation during the collapse of massive stars in the…
High-energy transients: thermonuclear (type-I) X-ray bursts
Duncan K. Galloway, Zac Johnston, Adelle Goodwin +1
Many distinct classes of high-energy variability have been observed in astrophysical sources, on a range of timescales. The widest range (spanning microseconds-decades) is found in…
The Regulated GeAs Cycles with the New Ga(p,)Ge and Ge(p,)As Reaction Rates and Their Impact on the GS 182624 Clocked Bursts and SAX J1808.43658 Photospheric Radius Expansion Bursts
Yi Hua Lam, Ning Lu, Alexander Heger +3
The Ga(p,)Ge and Ge(p,)As thermonuclear reactions connect the ZnGa and GeAs cycles by diverting the flow of the rapid proton capture process fro…
The Lack of Gamma-Ray Bursts from Population III Binaries
Krzysztof Belczynski, Tomasz Bulik, Alexander Heger +1
We study the evolution of first star (Population III) binaries. Under specific conditions, these stars may produce high redshift gamma-ray bursts (GRBs). We demonstrate that the oc…
The birth mass function of neutron stars
Zhi-Qiang You, Xingjiang Zhu, Xiaojin Liu +12
The birth mass function of neutron stars encodes rich information about supernova explosions, double star evolution, and properties of matter under extreme conditions. To date, it…
On the Sensitivity of Massive Star Nucleosynthesis and Evolution to Solar Abundances and to Uncertainties in Helium Burning Reaction Rates
Clarisse Tur, Alexander Heger, Sam M. Austin
We explore the dependence of pre-supernova evolution and supernova nucleosynthesis yields on the uncertainties in helium burning reaction rates. Using the revised solar abundances…
Explosions of blue supergiants from binary mergers for SN 1987A
Athira Menon, Victor Utrobin, Alexander Heger
Based on the work of Menon & Heger (2017), we present the bolometric light curvesand spectra of the explosions of blue supergiant progenitors from binary mergers. We study SN 1987A…
Black hole hyperaccretion inflow-outflow model. I. long and ultra-long gamma-ray bursts
Tong Liu, Cui-Ying Song, Bing Zhang +2
Long-duration gamma-ray bursts (LGRBs) and ultra-LGRBs (ULGRBs) originate from collapsars, in the center of which a newborn rotating stellar-mass black hole (BH) surrounded by a ma…
On the Detection of Supermassive Primordial Stars. II. Blue Supergiants
Marco Surace, Erik Zackrisson, Daniel J. Whalen +4
Supermassive primordial stars in hot, atomically-cooling haloes at 15 - 20 may have given birth to the first quasars in the universe. Most simulations of these rapidly acc…
-Process in Massive Carbon-Enhanced Metal-Poor Stars
Projjwal Banerjee, Yong-Zhong Qian, Alexander Heger
Observations suggest that the interstellar medium (ISM) might have been highly enriched in carbon at very early times. We explore nucleosynthesis in massive carbon-enhanced metal-p…
The Progenitor Stars of Gamma-Ray Bursts
Stan Woosley, Alexander Heger
Those massive stars that, during their deaths, give rise to gamma-ray bursts (GRBs) must be endowed with an unusually large amount of angular momentum in their inner regions, one t…
A benchmark for binary star interaction with a supermassive black hole in general relativity
Megha Sharma, Alexander Heger, Daniel J. Price +4
Most galaxies have supermassive black holes (SMBH) at their centres, surrounded by stars with binary systems also present in this environment. We use two schemes - post-Newtonian (…
The Regulated NiCu Cycles with the new Cu(p,)Zn reaction rate and the Influence on Type-I X-Ray Bursts: GS 182624 Clocked Burster
Yi Hua Lam, Ning Lu, Alexander Heger +5
During the X-ray bursts of GS 182624, "clocked burster", the nuclear reaction flow that surges through the rapid-proton capture process path has to pass through the NiCu cycles…
Pulsational pair instability as an explanation for the most luminous supernovae
S. E. Woosley, S. Blinnikov, Alexander Heger
The extremely luminous supernova SN 2006gy challenges the traditional view that the collapse of a stellar core is the only mechanism by which a massive star makes a supernova, beca…
Helium and Nitrogen Enrichment in Massive Main Sequence Stars: Mechanisms and Implications for the Origin of WNL Stars
Arpita Roy, Ralph S Sutherland, Mark R Krumholz +2
The evolutionary paths taken by massive stars with remain substantially uncertain. They begin their lives as main sequence (MS) O-stars. Dependin…
Pair-Instability Supernovae of Non-Zero Metallicity Stars
Ke-Jung Chen, Alexander Heger, Stan Woosley +2
Observational evidence suggests that some very massive stars in the local Universe may die as pair-instability supernovae. We present 2D simulations of the pair-instability superno…
Type Ibn supernovae from ultra-stripped supernova progenitors
Takashi J. Moriya, Bernhard Mueller, Sergei I. Blinnikov +4
Ultra-stripped supernovae are core-collapse supernovae from progenitors that lose a significant fraction of mass because of the binary interactions with their compact companion sta…
The spin-up of contracting red supergiants
Alexander Heger, Norbert Langer
We report on a mechanism which may lead to a spin-up of the surface of a rotating single star leaving the Hayashi line, which is much stronger than the spin-up expected from the me…
The Evolution of Surface Parameters of Rotating Massive Stars
Norbert Langer, Alexander Heger
We summarize the present status of the predictions of massive star models for the evolution of their surface properties. After discussing luminosity, temperature and chemical compo…
Spectacular nucleosynthesis from early massive stars
Alexander P. Ji, Sanjana Curtis, Nicholas Storm +39
Stars formed with initial mass over 50 Msun are very rare today, but they are thought to be more common in the early universe. The fates of those early, metal-poor, massive stars a…
Partial tidal disruption events: The elixir of life
Megha Sharma, Daniel J. Price, Alexander Heger
In our Galactic Center, about 10,000 to 100,000 stars are estimated to have survived tidal disruption events, resulting in partially disrupted remnants. These events occur when a s…
High Resolution Study of Presupernova Compactness
Tuguldur Sukhbold, Stan Woosley, Alexander Heger
The density structure surrounding the iron core of a massive star when it dies is known to have a major effect on whether or not the star explodes. Here we repeat previous surveys…
Nucleosynthesis in Primordial Hypernovae
J. J. Grimmett, Alexander Heger, Amanda I. Karakas +1
We investigate the relationship between explosion energy and nucleosynthesis in Population III supernovae and provide nucleosynthetic results for the explosions of stars with proge…
Sensitivity of Type I X-Ray Bursts to rp-Process Reaction Rates
A. Matthew Amthor, Daniel Galaviz, Alexander Heger +3
First steps have been taken in a more comprehensive study of the dependence of observables in Type I X-ray bursts on uncertain (p,gamma) reaction rates along the rp-process path. W…
On the Core-Collapse Supernova Explanation for LAMOST J1010+2358
S K Jeena, Projjwal Banerjee, Alexander Heger
Low-metallicity very massive stars with an initial mass of -- are expected to end their lives as pair-instability supernovae (PISNe). The abundance p…
Observatory science with eXTP
Jean J. M. in 't Zand, Enrico Bozzo, Jinlu Qu +181
In this White Paper we present the potential of the enhanced X-ray Timing and Polarimetry (eXTP) mission for studies related to Observatory Science targets. These include flaring s…
Convection and the Core -mode in Proto-Compact Stars -- A detailed analysis
Pia Jakobus, Bernhard Mueller, Alexander Heger
We present a detailed analysis of the dynamics of proto-compact star (PCS) convection and the core -mode in core-collapse supernovae based on general relativistic 2D and…
A wide star-black-hole binary system from radial-velocity measurements
Jifeng Liu, Haotong Zhang, Andrew W. Howard +52
All stellar mass black holes have hitherto been identified by X-rays emitted by gas that is accreting onto the black hole from a companion star. These systems are all binaries with…
Neutrino Losses in Type I Thermonuclear X-ray Bursts: An Improved Nuclear Energy Generation Approximation
Adelle J. Goodwin, Alexander Heger, Duncan K. Galloway
Type I X-ray bursts are thermonuclear explosions on the surface of accreting neutron stars. Hydrogen rich X-ray bursts burn protons far from the line of stability and can release e…
On the Maximum Mass of Accreting Primordial Supermassive Stars
T. E. Woods, Alexander Heger, Daniel J. Whalen +2
Supermassive primordial stars are suspected to be the progenitors of the most massive quasars at z~6. Previous studies of such stars were either unable to resolve hydrodynamical ti…