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    Archived pages: 415 . Archive date: 2014-09.

  • Title: Alexander Heger's Homepage
    Descriptive info: .. Dr.. Alexander Heger.. Professor.. Monash Centre for Astrophysics.. School of Mathematical Sciences.. Building 28.. Monash University.. ,.. Vic.. 3800.. Australia.. email:.. phone:.. +61-3-9905-4478.. fax:.. +61-3-9905-4403.. web:.. http://2sn.. org.. Class: (Semester 1/2014).. (archive).. M44011 The Sun and Stars.. Part I - Stars and Supernovae.. Research Group:.. Cosmic Explosions.. SINS: Stellar interiors and nucleosynthesis.. High Energy Astrophysics.. Student and Thesis Projects:.. stellar evolution, nuclear astrophysics, first stars,  ...   about specific projects.. (current and past projects).. Current Fields of Work:.. massive stars.. the first stars.. stellar rotation.. nucleosynthesis.. supernovae.. gamma-ray bursts.. x-ray bursts.. RESOURCES:.. StarFit.. How to set up ssh.. Python tools (Version 3).. /.. Version 2 (no longer updated).. IDL codes (no longer updated).. The DATA page.. About use of colors and color maps.. Publications and Preprints:.. ADS.. Google Scholar.. arXiv.. Thursday, 04-Sep-2014 16:47:14 AEST..

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  • Title: Call my office using Skype
    Descriptive info: The following iframe may call my office:..

    Original link path: /call.html
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  • Title: Alexander Heger's Class Archive
    Descriptive info: Class Archive.. Semester 1/2013.. M4111 The Sun and Stars.. Part II - Stars and Supernovae.. Semester 2/2012.. NIC XII School:.. Massive stars and core-collapse supernovae.. Spring 2012 (UMN).. PHYS-8801:.. Nuclear Physics I: Nuclear Astrophysics.. PHYS 8800:.. Nuclear Physics Seminar.. (organized by.. Meng-Ru Wu.. ).. Fall 2011 (UMN).. AST 4001:.. Stars and Stellar Evolution.. Laurens Keek.. Spring 2011 (UMN).. PHYS 1302W.. 100:.. Introductory Physics for Science and Engineering II.. (Spring 2011).. Spring 2010 (UMN).. 300:.. (Spring 2010).. AST 4994:.. Thesis  ...   Introductory Physics for Science and Engineering I.. (Fall 2009).. PHYS 5994:.. Directed Research.. (graduate students).. Spring 2009 (UMN).. 200:.. (Spring 2009).. PHYS 8200:.. Cosmology and High Energy Astrophysics - Seminar.. PHYS 8850:.. Neutrinos & Origin of Elements.. (guest lectures 3-5, Spring 2009).. AST 8021:.. Stellar Astrophysics.. (two guest lectures on stellar evolution and supernovae, Spring 2009).. Evan Frodermann.. AST 4990:.. (junior/senior undergradute students).. Fall 2008 (UMN).. Purnendu Chakraborty.. Fall 2007 (UCSC).. ASTR-112:.. Stellar Structure and Evolution.. Tuesday, 25-Feb-2014 19:09:56 AEDT..

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  • Title: Nucleosynthesis Data From Rauscher, Heger, Hoffman, & Woosley (2002)
    Descriptive info: Nucleosynthesis in Massive Stars.. Nucleosynthesis Data from Rauscher, Heger, Hoffman, & Woosley (2002).. Below we provide.. preliminary.. data sets.. Note that.. part of.. this data is not yet published in refereed journals and thus may be updated without notice.. We would appreciate if you contact us before using the data on this site for your publications.. Run names explained.. To uniquely identity the different runs on this page we use our "internal" naming convention rather than that used in various papers.. We hope this is not a major inconvenience for you.. Please feel free to contact us if you have any question.. The run mames have the following general structure:.. s.. 25.. a27.. d.. where.. is a sentianl for the model initial metallicity; "s" stands for solar composition.. gives the mass of the model in solar masses.. designates the nuclear reaction set used (for large network only; all models share the same structure and evolution).. is the sential for the supernova explosion "piston" that gave the desired explosion energy or nickel ejecta mass.. Below we give a brief matrix of model and how there were refenced in publications:.. internal name.. Rauscher et al.. (2002).. s15a28c.. S15.. s19a28g.. S19.. s20a28n.. S20.. s21a28g.. S21.. s25a28d.. S25.. s25a28j.. S25P.. s15a30c.. N15.. s20a30n.. N20.. s25a30d.. N25.. s25a32d.. H25.. List of the explosion models:.. explosion model / result.. s15.. c.. E.. kin.. = 1.. 2 foe.. s19.. g.. 2 foe / 0..  ...   rate.. 10.. a36.. NACRE + improved fit for high Ne22(a,n) rate.. 5.. a37.. NACRE + KAE lower limit Ne22(a,n) rate (HWW).. 7.. a38.. RATH + JAE Ne22(a,n) rate, but no (a,g).. 12.. a39.. RATH + no Ne22(a,n) rate, but KAE low "standard" (a,g).. 14.. a40.. RATH + no O16(n,g) (modified bdat file).. a41.. RATH + Fe59(n,g) rate reduced by 2 (modified bdat file).. Note:.. RATH = T.. Rauscher & F.. -K.. Thielemann, 2000, At.. Data Nucl.. Data Tables, 75, 1.. NACRE = C.. Angulo.. et al.. , Nucl.. Phys.. A, 656, 3.. HWW = R.. D.. Hoffman, S.. Woosley, & T.. A.. Weaver, 2001, ApJ, 549, 185.. ;.. rate data.. KAE = F.. Käppeler.. , 1994, ApJ, 437, 396.. JAE = M.. Jaeger.. , 2001, Phys.. Rev.. Lett.. 87, 202501.. Data sets.. (initial) ".. solar.. " mass fractions.. Presupernova structure data.. Presupernova composition data.. Postsupernova composition and yield data.. Movies.. Explosion of Model.. including updated neutrino nucleosynthesis.. content.. animated gif.. MPEG-1.. AVI.. bulk.. 9 MByte.. 5 MByte.. 8 MByte.. all.. 21 MByte.. 18 MByte.. 30 MByte.. radioactivities.. 0 MByte.. ---.. 19.. F.. 6 MByte.. g.. -process.. 138.. La.. 3 MByte.. 4 MByte.. 180.. Ta.. Acknowledgements:.. This work has been supported by the NSF (AST-9731569, INT-9726315), NASA (NAG5-8128), the DOE (B347885, W-7405-ENG-48, W-7405-ENG-36), the DOE SciDAC Program (DE-FC02-01ER41176), the Swiss National Science Foundation (2124-055832.. 98, 2000-061822.. 00) and the Alexander von Humboldt Foundation (FLF-1065004).. Tuesday, 23-Oct-2007 09:15:00 AEST..

    Original link path: /nucleosynthesis/RHHW02.shtml
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  • Title:
    Descriptive info: > Do you know of a way to download multiple files without upsetting the > spa.. umn connections limit? Two way, you can combine.. First, set up a tunnel! You can do all of it manually or add some of the things into you.. ssh/config file First, make the tunnel, pick a free port, like 2222 (need to see which are free, but most above 1024 should be) ssh -f -N -L 2222:b:22 zinger@ssh.. physics.. umn.. edu now your local port 2222 is forwarded to 22 on b you can also do several at once as in ssh -f \ -L 10222:b:22 \ -L 10322:c:22 \ -L 10422:d:22 \ -L 10522:e:22 \ -L 10622:f:22 \ -L 10722:g:22 \ -L 10822:h:22 \ -L 10922:i:22 \ -L 11122:k:22 \ -L 11222:l:22 \ -L 12222:v:22 \ -L 12322:w:22 \ -L 15022:localhost:22 \ -L 15222:wen:22 \ -L 15322:hou:22 \ -L 15422:behemoth:22 \ -L 15522:mc:22 \ -L 15622:vo:22 \ -N pp attached my script that also kills a running runnel using #!/bin/tcsh -fx set x=`ps -fC ssh | grep 10322:c:22 | cut -c 8-14` if ( $x != "" ) then kill -9 $x endif Next, you use the tunnel, do ssh -P 2222 alexey@localhost or to scp ssh -P 2222 alexey@localhost:[files] [local_files] or ssh -P 2222 [local_files] alexey@localhost:[files] Note that -P 2222 alexey@localhost stands for the remote machine! If you want to do things transparently and have a fast connection, you can use sshfs as well.. Then you would not need a tunnel, but could still use it.. mkdir x sshfs -P 2222 alexey@localhost:[directory_to_link] x than you can use the files in x as if they were local, read and write, just slow.. More conveninet is to make an ~/.. ssh/config file that only you can write otherwise it is ignored, maybe only you are allowed to read either, similar to the.. ssh directory For example, define Host b HostName localhost Port 2222 User alexey Host pp hostname physics.. edu User zinger Host * Compression yes CompressionLevel 9 ForwardX11 yes ForwardX11Trusted yes ForwardAgent yes Protocol 2 NoHostAuthenticationForLocalhost yes then you can use just 'b' where we  ...   write permission to other than yourself (so people can't modify your.. ssh).. use a passphrase for the key.. A good passphrase.. 1A) then, to start a using the ID ssh-agent tcsh ssh-add (if you use tcsh as shell, you could replace by whatever your shell is) 2) configure ssh to allow you do things easily.. You need to create/modify.. ssh/config at the *bottom* of the file you should have general configuration settings Host * Compression yes CompressionLevel 6 ForwardX11 yes ForwardAgent yes Protocol 2 NoHostAuthenticationForLocalhost yes above that, you specify your specific settings.. for example for the gateway Host s hostname sg1.. its.. monash.. edu.. au User galloway then you set up the port for the tunnel (port # can be arbitrary but > 10000, different for the different hosts # tunnel to xray Host x HostName localhost Port 10122 User duncan if you had another machine, say burst.. maths.. au, add # tunnel to burst Host b HostName localhost Port 10222 User duncan all these go *before* the general section the configuration file aliases "s" with sg1.. au and the tunnels to xray.. au to x, etc.. 3) set up the tunnel Now this is the only easy part.. after you did the above (you always need to do 1A before, in some distributions this is handled more transparently, you can open more terminals from within after you do this, all inherit the agent - should) ssh -f -N -L 10122:xray:22 -L 10222:burst:22 s after that, you should be able to just use x as remote for xray.. au for example, ssh x scp localfile x:remotefile scp localfile x:remotedir rsync -e ssh -vazu --progress mydir x: scp x:remotedir/remotefile.. with some luck, this works.. I have made this work many time, including macs, and at LANL, so it should be doable in most places.. what the tunnel "-L" does is for forward your local port (10122) to sgl which then sends the request to port 22 on xray as if it was coming from sgl.. These can be chained in case they make you go through more than one gateway.. ;-) -Alexander..

    Original link path: /ssh.txt
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  • Title: M44011 - Semester 1/2014 - The Sun and Stars
    Descriptive info: M44011 - Semester 1/2014 - The Sun and Stars.. Part I: Stars and Supernovae (Lectures 1-12).. [Part II: The Sun (Lectures 13-24) by Sergiy Shelyag].. Lecture 1: Equation of State of Stellar Gas.. Refs:.. Kippenhahn Weigert (1990), Sections 4.. 1, 8.. 1, 13, 15, 16.. Optional:.. 14 (ionization).. Lecture Notes.. Lecture 2: Stellar Structure.. Kippenhahn Weigert (1990), Sections 1, 2.. 1-2.. 5, 2.. 7, 3, 4.. 2-4.. 4, 5.. Summary:.. 9.. 10-12 (numerical solutions).. Homework (due March 13).. Lecture 3: Stellar Stability - Part I.. Kippenhahn Weigert (1990), Section 6.. 7.. Lecture 4: Stellar Stabiity - Part II.. Kippenhahn Weigert (1990), Sections 6.. Other matrials (optional):.. coffee glass, coffee  ...   1-19.. 10.. Lecture 6: Nuclear Reactions.. Kippenhahn Weigert (1990), Sections 8.. 2, 18.. 1, 18.. 5, 18.. 6.. 18.. 2-18.. 4.. Homework (due March 27).. Lecture 7: Nuclear Burning Phases in Stars.. Lecture 8: Evolution of Massive Stars.. Kippenhahn Weigert (1990), Sections 31.. 1-32.. 2, 31.. 5, 33.. 1-33.. 2.. 31.. 3-31.. Homework (due April 3).. Lecture 9: Supernovae.. Kippenhahn Weigert (1990), Section 34.. Lecture 10: Evolution of Low- and Intermediate-Mass Stars.. Kippenhahn Weigert (1990), Sections 33.. 3, 33.. Homework (due April 10).. Lecture 11: Evolution of the Sun.. Kippenhahn Weigert (1990), Sections 29.. Lecture 12: Neutron Stars.. Physics colloquium by Bennett Link.. (relevant for final).. Tuesday, 13-May-2014 20:41:26 AEST..

    Original link path: /Class/M44011-2014-S1/
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  • Title: Cosmic Explosions Group
    Descriptive info: Cosmic Explosions Group.. Working Group on Nuclear Astrophysics, Stars and Stellar Evolution, Supernovae, Nucleosynthesis, X-Ray Bursts and Neutron Stars, and the First Stars in the Universe.. Group Members.. Athira Menon (Monash).. - modelling of first stars and binaries.. Conrad Chan (Monash).. - multiple stars as progentors of ultra-metal poor stars.. Chen Hou (UMN/Monash).. - neutron star weather.. Pamela Vo (UMN).. - abundances and masses of the first stars.. Alexander Heger (Monash).. -.. kind of looking a bit into all of these.. Former Group Members.. Chris West (Metro State Collegue, Minnepolis).. - isotopic galactochemical history.. Ken Chen (UCSC, IAU Gruber Fellow).. the probably biggest thermonuclear explosions.. Alexey Zinger (UMN).. - giant erruptions in very massive  ...   burning in Type I XRBs.. Joel Kaardal (UCSD).. - transition to stable burning in H-free Type I XRBs.. Brian Crosby (MSU).. - very, very massive stars.. Joseph Barthel (UC Davies).. - lowest mass supernovae of the earliest stars.. Ryan Poitra (industry).. - the upper mass-limit for primordial supermassive stars.. Group Meetings.. Please join daily 11:00 coffee in the maths library, SINS group meetings, high-energy group meeetings.. This group is supported by US DOE through a block grant from nuclear physics, a topical collaboration in nuclear physics, the Joint Institute for Nuclear Astrophysics (JINA), the US NSF Astronomy program, the ARC through a Future Fellowship, Monash University through a Larkins Fellowship.. Wednesday, 26-Feb-2014 12:34:58 AEDT..

    Original link path: /cosmicexplosions/
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  • Title: Student Projects
    Descriptive info: PhD Thesis Projects.. Please contact me any time for PhD thesis projcts.. Possible projects comprise numerical simulation of evolution of massive stars, nucleosynthesis, supernovae.. Summer Student Projects.. The Neutrino HR Diagram.. Background:.. For millennia mankind has observed stars by eye, later by telescopes - optical, radio, X-rays, etc.. , but always if the form of electromagnetic radiation.. Accordingly, we typically record and classify the evolution of stars as function of their surface properties, i.. e.. , their surface temperature and their luminosity (the Hertzsprung-Russell (HR) Diagram).. But stars do not just radiate light, but also emit neutrino radiation.. In fact, even the sun emits about 7% of all its energy in the form of neutrinos.. So far, however, the only stars we have seen as neutrinos are the sun and the supernova 1987 A - detecting neutrinos is very hard, but technology is improving, so it is good to make predictions what we may see, or should see, some day.. In fact, evolved stars may shine 10,000,000,000 times more brightly in neutrinos at the end of their life as they shine in visible light - so observing a star in neutrinos tells us that is very close to death, maybe weeks to hours - and give us an early warning about an impending supernova.. Additionally, neutrinos not only have an energy spectrum like electromagnetic radiation, but they also have "flavour" as a "colour".. Project Outline:.. The goal of this project is produce the counterpart of such an HR diagram but for neutrinos and make graphical representations.. How would stellar evolution tracks look? Maybe including supernovae? How would snapshots of different astronomical objects like star clusters or galaxies look?.. Project Details:.. Supervisors:.. Prof Alexander Heger (MoCA/School of Mathematical Sciences).. Duration:.. 6-8 weeks.. Start/End date:.. Nov-Feb, to be agreed with supervisor.. Prerequisites:.. Experience or willing to learn prior to project start:.. Computer/programming skills: Python3, Fortran.. Familiarity with Linux / UNIX shell on MacOS.. Desired:.. Astrophysics/computational astrophysics be an advantage.. Strong maths and physics background.. The Nature of the First Stars.. After the Big Bang it took about 300,000,000 yr before the first stars would form - now some 13,000,000,000 yr ago.. Unfortunately, we can no longer observe these stars today directly, even with our best telescopes.. But there is still some "fossil" record of them left behind, preserved in the oldest stars in our galaxy we can observe, dating back to pre-galactic times.. When the first stars exploded as supernovae, their ashes were dispersed and the next generation of stars formed, incorporating some of these supernova debris.. We can now measure these abundance patterns in those old stars (in particular done by astronomers in Australia, including Physics Nobel Prize Laureate Brian Schmidt, and using telescopes here in Australia and the largest telescopes in the world in Hawaii and Chile).. In fact, we have a rapidly growing catalogue of them.. To some extent, hence, the abundance patterns are similar to a genetic fingerprint that allows to identify the parents.. The goal of this project is to identify the "parents" of these old stars in our galaxy, i.. , find out about the now "extinct" first stars in the universe - what their properties where, how they lived and died - and even how many parents there were, how different or alike they were.. For this we have to create a data base of predicted abundance patterns of supernovae from the first generation of stars (picture left/above) to compare with the elements observed in the old stars.. Your work will be help creating the data base and to compare with the most recent data we have and develop some analysis tools to allow you do this task.. References.. A single low-energy, iron-poor supernova as the source of metals in the star SMSS J031300.. 36 670839.. 3.. , S.. C.. Keller, M.. S.. Bessell, A.. Frebel, A.. R.. Casey, M.. Asplund, H.. Jacobson, K.. Lind, J.. Norris, D.. Yong, A.. Heger, Z.. Magic, G.. Da Costa, B.. P.. Schmidt & P.. Tisserand, Nature 506, 463 466 (2014).. The Most Common Thermonuclear Explosions in the Universe: Type I X-ray Bursts.. The lifetime of a star is highly dependent upon its initial mass: the sun will shine for a total of about 10 billion years; for a star 25 times the mass of the sun this reduces to a mere 10 million years.. When a star of about ten solar masses or more reaches the end of its life, it may explode as a supernova and leave behind a neutron star or black hole.. But many stars are not single.. Instead, they may have a close companion star.. These are called binary star systems.. In some cases the secondary star has much lower mass than the primary star and hence way outlive its more massive partner.. If the two stars are close enough and the secondary star expands as it evolves, it may transfer mass to the remnant of the primary star.. The mass then spirals inward toward the star in an accretion disk emitting X-rays.. In case the remnant is a neutron star, the accreted material accumulates on the surface of the neutron star.. When the accreted layer gets big enough, it can ignite in a bright thermonuclear flash incinerating the accreted layer of nuclear fuel.. We can observe such flashes as Type I X-ray bursts throughout the entire galaxy.. The bursts last just seconds and recur on a time scale of hours to days.. Considering there is some hundred of such systems active in our galaxy, this makes them the most common thermonuclear explosion to occur in nature.. The goal of this project is to model such Type I X-Ray bursts in a special kind of system: stars in which the companion is a helium white dwarf stars, hence the accreted material is mostly pure helium.. These are much easier to model than system that accrete material which also contains hydrogen.. You will be using a hydrodynamic code to simulate such bursts for a variety of conditions, study their behaviour, and compare to observational data.. Dr Duncan Galloway (MoCA/School of Mathematical Sciences/School of Physics).. The Cosmic Forge: Supernovae and their Nucleosynthesis.. When massive stars of about ten times the mass of the sun or more reach the end of their life, their centre collapses to a neutron star or a black hole.. At the same time, a supernova shock front may be launched that that disrupts the stars such that much of the nucleosynthesis products the star has made throughout its life are ejected, to finally make new stars or become parts of planets and form the basis for life.. As the shock travels through the star, it also causes some explosive burning in the innermost material that changes the composition of the material that is actually ejected.. The tremendous neutrino flux emanating from the newly born neutron star additional contributories by transforming or splitting some of the nuclei.. A huge uncertainty, however, is with how much energy the star actually explodes, even if we know its entire structure prior to the supernova explosion.. And this, of course, changes which elements the star forges and how much of each it expels.. The goal of this project is to study the nucleosynthesis of supernovae using an analytic model for supernova explosions.. This model makes some assumptions about certain physical parameters of the explosion.. Your task will be to study the how the nucleosynthesis products of the star change as the model is adjusted.. The results can be compared to the ratio of isotopes and elements as we find them in the milky way, in the sun, and on earth, helping you to constrain which parameters are physically realistic.. This way you can constrain the properties of dying stars, simply put, just be looking at the composition of a piece of rock you may find in your garden.. Dr Bernhard Mueller (MoCA/School of Mathematical Sciences).. Strong maths background.. Strong background in stellar evolution and/or nuclear astrophysics.. Honours Student Projects.. How fast do old stars rotate inside?.. John Lattanzio.. Paul Cally.. The Kepler satellite mission became famous for finding hundreds of new planets around stars.. To  ...   up.. The goal of this project is to find how such stars with primordial composition and high accretion rates evolve and approach the point of collapse to a supermassive black hole, as a function of this accretion rate.. And, in particular, what the mass of the star is by the time it collapses, i.. , what is the mass of the black holes formed.. For example, is there an upper mass limit, and is this different from the one obtained for stars with a given fixed initial mass (see other project).. 2013ApJ.. 777.. 99W.. How the Oldest Stars Known Were Made.. Constraining Supernovae Properties by their Nucleosynthesis.. Most heavy elements from oxygen to iron are dominantly made by the deaths of massive stars as supernovae.. Whereas fully understanding such core collapse supernovae requires multi-dimensional simulations including complicated and expensive radiation transport physics, there is some progress in developing simpler approximation formulae for these supernovae given the structure of the star at the time of its death.. Depending on the explosion properties, supernovae synthesise and eject elements in different proportions, which can be used as a diagnostic of the explosion model.. For this project you will use an analytic model for supernova explosions and their energies to simulate the nucleosynthesis of these stars.. The result is to be compared to the abundance patterns - elemental and isotopic - that we find in the in the universe today, in the sun, and on earth.. The goal of the project is to constrain the properties of the analytic supernovae model in its ability to reproduce the observed data.. 2012ARNPS.. 62.. 407J.. arxiv.. org/abs/1409.. 0540.. 2002RvMP.. 74.. 1015W.. 576.. 323R.. Supernovae Making Neutron Stars or Black Holes?.. When a massive star reaches the end if its life, the core collapses into a neutron star or, possibly, a black hole.. In many cases, at first a shock is launched moving outward, ejecting the outer layers of the star.. But there may not be enough energy to eject the entire core, or there can be hydrodynamic interactions in the envelope that push some of the matter onto the central object.. How much of the material falls back will determine the final mass of the compact remnant that is left behind.. If the mass exceeds the maximum mass for a neutron star, it will collapse to a black hole.. For this project you will use an analytic model for supernova explosions and their energies to simulate the explosion of these stars.. You will then use a one-dimensional hydrodynamic code modified for proper inner boundary conditions, to simulate the dynamics of the explosion and how much mass is ejected or fall back.. This will allow you to estimate the remnant mass (some of the rest mass is carried away by neutrinos).. Using a range of supernova progenitor models, you can make perditions about the distribution of neutron star and black hole masses.. 2008ApJ.. 679.. 639Z.. 591.. 288H.. Previous Projects (Monash).. Honours Projects.. Supermassive Stars: Explode or Die?.. The student will use a hydrodynamic stellar evolution code that includes thermonuclear burning and post-Newtonian corrections for general relativity for non-rotating stars.. One possible extension of the project is to modify the stellar evolution code to include post-Newtonian corrections for rotating stars; another extension could be to follow the neutrino signal of collapsing stars and the neutrino-induced nucleosynthesis in the envelope of the star, as well as a possible explosion due to the mass carried away by the neutrinos.. Summer Vacation Projects.. The Genes of the Oldest Stars.. (The Stellar Jurassic Park).. We can now measure these abundance patterns in those old stars (in particular done by astronomers in Australia, including Physics Nobel Prize Laureate Brian Schmidt, and using telescopes here and the largest telescopes in the world in Hawaii and Chile).. We want to use a genetic algorithm (an optimization method) to find a match and combination of "ashes" from theoretical models in a large data base containing a wide variety of stellar models and supernova and compare to observational data.. The student's task will be to develop a code using a genetic algorithm as optimization method to find out which theoretical data (relative abundances of chemical elements) best matches the our best current observations.. Some basic programming experience would be advantageous, some mathematical skills are required, but you definitively need to bring the willingness to learn.. Are you ready to recreate "The Stellar Jurassic Park"?.. Prof Alexander Heger (MoCA/School of Mathematical Sciences).. Dr Aldeida Aleti (Faculty of Information Technology).. 6-10 weeks.. to be decided with supervisor, most likely Dec-Feb.. Supernova Archaeology.. For some supernova remnants like Cas A we now have detailed observational data that give is distance from the center and velocity w/r the observer.. Usually astronomers assume homologous expansion of the ejecta - velocity just scales linearly with distance from the center.. Using this relation, various structures in the supernova have been recovered, in 3D, some of them rather surprising, like planar "walls" of material.. But are these structures real or just an artifact of the reconstruction procedure? The goal of this project is explore different velocity distributions of the ejecta and how they would appear when reconstructed using the assumption of homologous expansion mentioned above.. Assume, for example, some ejecta would come out as a bubble on one side, as we find in supernova simulations.. How would such a structure appear? Using and developing 3D visualization as well as data from the literature and publications are essential parts of this project.. Previous Projects (UMN).. (in progress).. OpenCL Sparce Matrix Solver.. (computer science).. Implement space matrix solver for CUDA (nVidia graphics card) or OpenCL to accelerate nuclear reaction network solver on current and future computer hardware.. Lowest M/Z ONeMg WD.. (astrophysics).. Determine the minimum mass for making ONeMg white dwarf stars at the lowest metallicities.. How does stellar evolution change for very- and ulta-metal poor stars?.. Lowest M/Z supernovae.. Determine the minimum mass for core collapse supernovae at the lowest metallicities.. Heavy Metal Snowstorms.. (theoretical/astrophysics).. 1D simulations of instabilities inside accreting neutron stars due to phase separation.. This project may also require some theoretical work, maybe some background in condensed matter physics.. Type I X-ray bursts.. Multi-D simulations of mixing and burning in the thermonuclear runaway of a thin layer of accreted material on neutron stars in a binary star system.. Consistent data mapping.. (computational fluid dynamics).. Implement algorithm to conservatively map data from 1D Lagrangian coordinate system to multi-D Eulerian coordinates as initial conditions for numerical simulations.. Use multi-D simulations to assess quality of mapping.. More than very massive stars.. Study the evolution of stars that collapse to black holes beyond the "classical" limit of very massive stars.. How does the evolution of stars change in that mass range?.. Evolution of supermassive stars.. Determine the mass limits and dependence on initial conditions, for which supermassive stars collapse, and which still burn, and for how long, before they collpase.. Supermassive Supernovae.. Determine mass limits as a function of metallicity as well as dependence on initial conditions, for which supermassive stars explode.. Evolution of the Sun.. (astrophysics, thesis/directed research).. Numerical simulations (1D) of the evolution of the Sun.. Try to reproduce the current Sun at the current age, and follow the evolution to late times.. How will the sun end it life?.. AGB stars.. Follow the evolution of and intermediate mass stars to late times.. Simulate nucleosynthesis in these stars.. Supernova remnant masses.. Perform numerical simulations of fallback ejecta after a supernova explosion to determine the mass and type of the remnant.. Is a neutron star or a black hole formed?.. IMF of the First Stars.. (astrophysics, graduate student).. Match nucleosynthesis patterns of observed metal-poor stars to nucleosynthesis predictions from stellar models.. Try to deduce what stellar masses are the best fit to the observed abunacne patterns.. Develop a tool and plotting to also incorporate isotopes.. Galactochemical Evolution.. Determine the evolution of different components of nucleosynthesis products (r-, s-, p-process, etc.. ) as a function of metallicity.. Combine observational data for the evolution of different elements with that of different components for isotopes from nuclear data and nucleosynthesis studies.. Construct isotopic galactochemical history of the universe..

    Original link path: /Projects/
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  • Title: Stellar Evolution
    Descriptive info: Stellar Evolution Modelling.. Project page for studies of stellar evolution.. Project Members.. Stan Woosley.. Norbert Langer.. Isabelle Baraffe.. Henk Spruit.. Data Files.. Note that part of the data sets provided below may be.. and that part of them could change without notice.. Rotating presupernova models from Heger, Langer, & Woosley (2000).. Non-rotating pre-supernova models from Woosley, Heger, Weaver (2002).. Magnetic rotating presupernova models from Heger, Woosley, & Spruit (2004).. More data files will become available on this site in the future.. Please contact us if your require additional data files or output quantities.. The movies are composed from a series of Kippenhahn Diagrams,.. i.. , stellar structure as a function of time, which vary one parameter of the star.. All sequences use the same color coding:.. convection.. semiconvection.. net nuclear energy.. generation.. (burning plus neutrino losses) in erg g.. -1.. 9.. 11..  ...   stars.. The last 100,000 yr of the inner 10 solar masses of a massive star.. metallicity.. fine grid.. reduced grid.. (animated gif).. (mpeg-1).. 1 MByte.. 441 kByte.. 842 kByte.. -4.. 896 kByte.. The whole life of a massive star.. large grid.. 2 MByte.. 811 kByte.. 7 MByte.. ---.. 14 MByte.. 15 MByte.. 29 MByte.. C12(a,g) rate study.. The movies shown here are based on a thesis project by M.. M.. Boyes.. in collaboration with A.. Woosley.. The movies magnify the evolution of the helium core starting at end of central helium burning till core collapse.. Movies by Alexander Heger.. mass.. (solar masses).. 15.. 737 kByte.. 20.. 750 kByte.. 744 kByte.. This work has been supported by the NSF (AST-9731569, INT-9726315), NASA (NAG5-8128), the DOE (B347885, W-7405-ENG-48), the DOE SciDAC program (DE-FC02-01ER41176), and the Alexander von Humboldt Foundation (FLF-1065004).. Monday, 05-Dec-2011 22:55:31 AEDT..

    Original link path: /stellarevolution/
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  • Title: Stellar Evolution Data Page
    Descriptive info: Grids of Stellar Evolution Models.. Presupernova Structure of Rotating Stars.. Data from Heger, Langer, & Woosley (2000).. Hydro / EOS data explanation.. column.. data.. unit.. grid.. cell number.. cell outer total mass.. mass coordinate at the cell top interface.. cell outer radius.. radius coordinate at the cell top interface.. cm.. cell outer velocity.. velocity of the cell top interface.. cm s.. cell density.. average density of the cell.. g cm.. -3.. cell temperature.. average temperature of the cell.. K.. cell pressure.. average pressure of the cell.. dyn cm.. -2.. cell specific energy.. average specific energy of the cell.. erg g.. cell specific entropy.. average specific entropy of cell.. k.. B.. baryon.. cell angular velocity.. average angular velocity of the cell.. rad s.. cell A_bar.. average mean mass number of nuclei in the cell.. cell Y_e.. average electrons per baryon in the cell.. stability.. hydrodynamic stability of outer cell boundary.. Network data explanation.. APPROX.. :.. approximative 19 isotope network.. QSE.. Quasi Statitstical Equilibrium.. isotopes treated in three NSE subgroups which are connected by "bottleneck" reactions.. 137 isotope network for weak rates.. NSE.. Nuclear Statistical Equilibrium.. network.. APPROX.. QSE / NSE..  ...   54.. Fe (+.. Fe).. A approximately 2*Z+2, Iron Peak.. Ni56.. A 2*Z+2, Iron Peak.. Fe56.. Fe only.. 'Fe'.. A 2*Z + 3, Iron Peak, excluding.. The Data.. Stars of solar initial metallicity, strong molecular weight barriers.. In Heger, Langer, & Woosley (2000) these are the models of the "B" series, i.. , E15B etc.. ZAMS equatorial rotation velocity.. 0 km/s.. 100 km/s.. 200 km/s.. 300 km/s.. 0.. 169 kByte.. 172 kByte.. 173 kByte.. 180 kByte.. 188 kByte.. 194 kByte.. 195 kByte.. 191 kByte.. Stars of solar initial metallicity, weak mean molecular weight barriers.. In Heger, Langer, & Woosley (2000) these are the models of the series without "B", i.. , E15 etc.. 181 kByte.. 197 kByte.. 203 kByte.. 196 kByte.. 130 kByte.. This work has been supported by Prime Contract No.. W-7405-ENG-48 between The Regents of the University of California and the United States Department of Energy, by the Deutsche Forschungsgemeinschaft through grants La 587/15 and La 587/16, by the National Science Foundation (AST 97-31569) and by the Alexander von Humboldt Foundation.. AH was, in part, supported by a "Doktorandenstipendium aus Mitteln des 2.. Hochschulprograms".. Thursday, 26-Aug-2004 03:51:55 AEST..

    Original link path: /stellarevolution/rotation/
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  • Title: Nucleosynthesis
    Descriptive info: Project page for studies of nucleosynthesis in massive stars.. Candace Church.. Rob Hoffman.. Clarisse Tur.. Sam Austin.. Weiqun Zhang.. Tommy Rauscher.. Matt Boyes.. A new study of C12(a,g) and 3a reaction rates.. Data files from Heger & Woosley rotating models (2009).. Data files from Rauscher, Heger, Hoffman, & Woosley (2002).. Data files from Woosley & Heger (2007).. Publications.. Nucleosynthesis in Massive Stars with Improved Nuclear and Stellar Physics.. by T.. Rauscher, A.. Heger, R.. Hoffman, & S.. Woosley (2002, ApJ, 576, 323;.. abstract.. full text.. astro-ph/0112478.. Nucleosynthesis of Heavy Elements in Massive Stars.. Heger, S.. Woosley, K.. Langanke, E.. Kolbe, T.. Rauscher, & R.. D.. Hoffman (2002, in proceedings of.. Nuclei in the Cosmos VII.. , in press).. Nuclear Data Need for the Study of Nucleosynthesis in Massive Stars.. by S.. Woosley, A.. Heger, T.. Hydrostatic and Explosive Nucleosynthesis in Massive Stars Using Improved Nuclear and Stellar Physics.. Woosley (2002, in proceedings of.. New Results on Nucleosynthesis in Massive Stars; Nuclear Data Needs for Nucleosynthesis.. by R.. Hoffman,  ...   Astronomy Reviews, eds.. Diehl, D.. Hartmann, P.. Hoppe, N.. Prantzos;.. astro-ph/0110015.. Nuclear Aspects of the n- and s-Process in Massive Stars.. Woosley, & R.. Hoffman (2001, to appear in.. Proc.. 9th Int.. Seminar on Interactions of Neutrons with Nuclei (ISINN-9), Dubna, Russia, May 2001.. astro-ph/0106289.. Nucleosynthesis in Massive Stars Using Extended Adaptive Nuclear Reaction Networks.. Woosley (2001,.. Tours Symposium on Nuclear Physics IV.. , eds.. Arnould et al.. , AIP Conference Proceedings, 561, 3 - 12).. Nucleosynthesis in stars revisited.. Nuclei in the Cosmos 2000.. Langanke and J.. Christensen-Dalsgaard, Amsterdam: Elsevier; Nuclear Physics A, 688, p.. 193c - 196c;.. astro-ph/0010021.. Nuclear Aspects of Nucleosynthesis in Massive Stars.. Woosley (2001, in.. Hadrons, Nuclei, and Applications.. G.. Bonsignori, M.. Bruno, A.. Ventura, D.. Vretenar, World Scientific, p.. 277;.. nucl-th/0008065.. Nucleosynthesis in Massive Stars Including All Stable Isotopes.. Rauscher, & S.. Woosley (2000, in proceedings of the.. 10th Workshop on Nuclear Astrophysics.. , Ringberg Castle, eds.. Müller and W.. Hillebrandt, MPA Proceedings P12, Garching, p.. 105,.. astro-ph/0006350.. Saturday, 16-Jul-2011 06:09:17 AEST..

    Original link path: /nucleosynthesis/
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