Prof. Raphael Hirschi

Title: Professor of Stellar Hydrodynamics and Nuclear Astrophysics
Phone: (+44) 01782 7 33324
Email: r.hirschi@keele.ac.uk
Location: Lennard-Jones 2.09
Role:
Contacting me: Phone, email me or come to my office
Hirschi_Raphael

I completed a MSc in Physics at the Swiss Polytechnic School (EPFL) in Lausanne in 1999 and a PhD in Astrophysics at the Geneva Observatory in 2004. During his PhD, I improved computer models of massive stars to determine their fate (black hole or neutron star), work for which I received the Plantamour-Prevost Prize. I then went to the University of Basel as a Post-doctoral fellow to answer the question: “In which stars are the chemical elements we are made of created?”. Since joining Keele University in 2007 as an RCUK academic fellow, major highlights of my research include: the determination of the mass and fate of the most massive stars known to date, explaining unique abundances in the early Universe and the setting-up and leading of large projects (ERC starting grant for SHYNE project 2012-2017) and collaborations (NUGRID, BRIDGCE, ChETEC COST Action). I was promoted to Reader in 2013 and Professor in 2018.

Stars play a key role in the universe through the light they shine, all the chemical elements they produce and the supernova explosions that mark their death. They can be used to probe the universe and its evolution from its infancy. The first stars formed approximately 400 million years after the Big Bang. Even if most of those first stars and subsequent generations are long dead, their chemical "fingerprints" are stored in low-mass stars that have a total lifetime longer than the age of the universe. In particular, extremely metal-poor low-mass stars enable us to study the first stars and the early universe. Using stars and nucleosynthesis as probes of the universe requires a multi-disciplinary approach developing synergy between astronomical observations, nuclear physics experiments and stellar evolution models. The need for multi-disciplinary approaches to tackle key scientific challenges is not new. For example, 100 years ago, Albert Einstein collaborated with mathematician Marcel Grossmann to develop the theory of General Relativity. Multi-disciplinary research is strongly supported in Europe via the ERC frontiers science grants. The UK and Europe play a leading role in the multi-disciplinary research area of stellar nucleosynthesis, thanks to state-of-the-art observing (ESO-VLT, ESA-Gaia) and nuclear experimental (e.g. CERN, LUNA) facilities. For example, Observers find the most metal-poor stars using the VLT, challenging theories of star formation. The LUNA nuclear facility in Italy measured the key reaction of the CNO cycle, the 14N(p,g) reaction in the Gamow window, removing extrapolation uncertainties. Furthermore, next-generation facilities (ESO E-ELT,FAIR@GSI) are being built, which represent billions of Euros in investments.

To maximise return on these huge investments, an improved theoretical framework of interpretation is crucially needed. Theoretical models are lagging far behind observational and experimental efforts. Next-generation stellar evolution models matching these next-generation facilities are therefore the primary objective of the my research.

Due to the complex nature of stars, stellar models would ideally require three-dimensional (3D) hydrodynamic models that include all the relevant physics (convection, rotation, magnetic fields, binary interactions, mass loss). 3D hydro models must use time steps that are at most days (max convective turnover time is ~200 days for red giants). The total lifetime of stars, however, is at least 2 million years. This means it will not be possible to model the full evolution of stars with 3D models in the near future. This explains why most stellar evolution models are limited to (spherically-symmetric) one dimension (1D). There is a long and successful tradition of 1D stellar evolution with many codes developed in different countries. The models produced with these codes have many applications in astrophysics. They are used as a theoretical framework of interpretation for observational surveys (e.g. VLT Flames survey of massive stars), as well as input for supernova simulations, galactic chemical evolution simulations and asteroseismology studies. They are also used to resolve as yet unexplained observations. For example, my group's stellar evolution models explain unique abundances in extremely metal-poor stars (Cescutti,., Hirschi et al 2013) and the oldest globular cluster of the galactic bulge, thus creating for the first time a link between these two populations (Chiappini,.., Hirschi et al 2011, Nature). My group's very massive star models "weighed" the most massive stars discovered to date (Crowther,.,Hirschi et al 2010). The masses determined (up to 320 solar masses at birth) drastically upset the previous upper mass limit of stars, which was around 150 solar masses.

The predictive power of stellar evolution, however, is crippled by 1D prescriptions of 3D phenomena containing free parameters, which need to be tuned to reproduce subsets of observations. A key uncertain prescription in 1D codes is that of convection, in particular convective boundary mixing (CBM). Even though 3D hydro simulations cannot follow the entire evolution of stars, computing power has finally reached the point where convective boundaries can be resolved in the largest simulations. This means that now these simulations can provide the guidance and constraints to build the next generation of stellar evolution models including 3D-hydro-based prescriptions for convective boundary mixing. Very importantly, the constraints from 3D simulations are independent of astronomical observations and thus provide a unique new insight into CBM. The goal of my research is to constrain, improve and establish new 1D prescriptions using 3D simulations and incorporate these new prescriptions into 1D stellar models. These latest 3D models require the largest computers on the planet. The development of these computers represents a multi-disciplinary effort between applied computer science, applied mathematics and (astro-)physics, the other key multi-disciplinary aspect of my research.

The goal of my theoretical research is thus to link major nuclear physics experiments to large astronomical observing programmes, hydrodynamics simulations to stellar models and theoretical stellar astrophysics to the high performance computing industry. To work towards these goals, I currently chair the ChETEC COST Action: http://www.chetec.eu/ .


See my personal web page for further information.

[Same link as before for personal webpage: http://www.astro.keele.ac.uk/~hirschi/]

Selected Publications

  • Choplin A, Hirschi R, Meynet G, Ekstrom S. 2017. Are some CEMP-s stars the daughters of spinstars?. ASTRONOMY & ASTROPHYSICS, vol. 607, Article ARTN L3. link> doi>
  • Cristini A, Meakin C, Hirschi R, Arnett D, Georgy C, Viallet M, Walkington I. 2017. 3D hydrodynamic simulations of carbon burning in massive stars. Monthly Notices of the Royal Astronomical Society, vol. 471(1), 279-300. link> doi>
  • Choplin A, Ekstrom S, Meynet G, Maeder A, Georgy C, Hirschi R. 2017. Pre-supernova mixing in CEMP-no source stars. ASTRONOMY & ASTROPHYSICS, vol. 605, Article ARTN A63. link> doi>
  • Gilmer MS, Kozyreva A, Hirschi R, Frohlich C, Yusof N. 2017. Pair-instability Supernova Simulations: Progenitor Evolution, Explosion, and Light Curves. ASTROPHYSICAL JOURNAL, vol. 846(2), Article ARTN 100. link> doi>
  • Nishimura N, Hirschi R, Rauscher T, Murphy ASJ, Cescutti G. 2017. Uncertainties in s-process nucleosynthesis in massive stars determined by Monte Carlo variations. MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, vol. 469(2), 1752-1767. link> doi>

Full Publications List show

Journal Articles

  • Choplin A, Hirschi R, Meynet G, Ekstrom S. 2017. Are some CEMP-s stars the daughters of spinstars?. ASTRONOMY & ASTROPHYSICS, vol. 607, Article ARTN L3. link> doi>
  • Cristini A, Meakin C, Hirschi R, Arnett D, Georgy C, Viallet M, Walkington I. 2017. 3D hydrodynamic simulations of carbon burning in massive stars. Monthly Notices of the Royal Astronomical Society, vol. 471(1), 279-300. link> doi>
  • Choplin A, Ekstrom S, Meynet G, Maeder A, Georgy C, Hirschi R. 2017. Pre-supernova mixing in CEMP-no source stars. ASTRONOMY & ASTROPHYSICS, vol. 605, Article ARTN A63. link> doi>
  • Gilmer MS, Kozyreva A, Hirschi R, Frohlich C, Yusof N. 2017. Pair-instability Supernova Simulations: Progenitor Evolution, Explosion, and Light Curves. ASTROPHYSICAL JOURNAL, vol. 846(2), Article ARTN 100. link> doi>
  • Nishimura N, Hirschi R, Rauscher T, Murphy ASJ, Cescutti G. 2017. Uncertainties in s-process nucleosynthesis in massive stars determined by Monte Carlo variations. MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, vol. 469(2), 1752-1767. link> doi>
  • Edelmann PVF, Roepke FK, Hirschi R, Georgy C, Jones S. 2017. Testing a one-dimensional prescription of dynamical shear mixing with a two-dimensional hydrodynamic simulation. ASTRONOMY & ASTROPHYSICS, vol. 604, Article ARTN A25. link> doi>
  • Pignatari M, Hoppe P, Trappitsch R, Fryer C, Timmes FX, Herwig F, Hirschi R. 2017. The neutron capture process in the He shell in core-collapse suprenovae: Presolar silicon carbide grains as a diagnostic tool for nuclear astrophysics. Geochimica et Cosmochimica Acta. doi> link>
  • Yong D, Norris JE, Da Costa GS, Stanford LM, Karakas AI, Shingles LJ, Hirschi R, Pignatari M. 2017. A Chemical Signature from Fast-rotating Low-metallicity Massive Stars: ROA 276 in omega Centauri. ASTROPHYSICAL JOURNAL, vol. 837(2), Article ARTN 176. link> doi>
  • Eggenberger P, Lagarde N, Miglio A, Montalban J, Ekstrom S, Georgy C, Meynet G, Salmon S, Ceillier T, Garcia RA, Mathis S, Deheuvels S, Maeder A, den Hartogh JW, Hirschi R. 2017. Constraining the efficiency of angular momentum transport with asteroseismology of red giants: the effect of stellar mass. ASTRONOMY & ASTROPHYSICS, vol. 599, Article ARTN A18. link> doi>
  • Georgy C, Meynet G, Ekstrom S, Wade GA, Petit V, Keszthelyi Z, Hirschi R. 2017. Possible pair-instability supernovae at solar metallicity from magnetic stellar progenitors. ASTRONOMY & ASTROPHYSICS, vol. 599, Article ARTN L5. link> doi>
  • Kozyreva A, Gilmer M, Hirschi R, Frohlich C, Blinnikov S, Wollaeger RT, Noebauer UM, van Rossum DR, Heger A, Even WP, Waldman R, Tolstov A, Chatzopoulos E, Sorokina E. 2017. Fast evolving pair-instability supernova models: evolution, explosion, light curves. MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, vol. 464(3), 2854-2865. link> doi>
  • Siqueira-Mello C, Chiappini C, Barbuy B, Freeman K, Ness M, Depagne E, Cantelli E, Pignatari M, Hirschi R, Frischknecht U, Meynet G, Maeder A. 2016. Looking for imprints of the first stellar generations in metal-poor bulge field stars. ASTRONOMY & ASTROPHYSICS, vol. 593, Article ARTN A79. link> doi>
  • Rauscher T, Nishimura N, Hirschi R, Cescutti G, Murphy ASJ, Heger A. 2016. Uncertainties in the production of p nuclei in massive stars obtained from Monte Carlo variations. MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, vol. 463(4), 4153-4166. link> doi>
  • Pignatari M, Herwig F, Hirschi R, Bennett M, Rockefeller G, Fryer C, Timmes FX, Ritter C, Heger A, Jones S, Battino U, Dotter A, Trappitsch R, Diehl S, Frischknecht U, Hungerford A, Magkotsios G, Travaglio C, Young P. NUGRID STELLAR DATA SET. I. STELLAR YIELDS FROM H TO BI FOR STARS WITH METALLICITIES Z=0.02 and Z=0.01. ASTROPHYSICAL JOURNAL SUPPLEMENT SERIES, vol. 225(2), Article ARTN 24. link> doi> link>
  • Battino U, Pignatari M, Ritter C, Herwig F, Denisenkov P, Den Hartogh JW, Trappitsch R, Hirschi R, Freytag B, Thielemann F, Paxton B. 2016. APPLICATION OF A THEORY AND SIMULATION-BASED CONVECTIVE BOUNDARY MIXING MODEL FOR AGB STAR EVOLUTION AND NUCLEOSYNTHESIS. ASTROPHYSICAL JOURNAL, vol. 827(1), Article ARTN 30. link> doi>
  • Kozyreva A, Hirschi R, Blinnikov S, Hartogh JD. 2016. How much radioactive nickel does ASASSN-15lh require?. Monthly Notices of the Royal Astronomical Society, vol. 459(1). link> doi> link>
  • Cristini A, Meakin C, Hirschi R, Arnett D, Georgy C, Viallet M. 2016. Linking 1D evolutionary to 3D hydrodynamical simulations of massive stars. PHYSICA SCRIPTA, vol. 91(3), Article ARTN 034006. link> doi>
  • Frischknecht U, Hirschi R, Pignatari M, Maeder A, Meynet G, Chiappini C, Thielemann F-K, Rauscher T, Georgy C, Ekstroem S. 2016. s-process production in rotating massive stars at solar and low metallicities. MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, vol. 456(2), 1803-1825. link> doi> link>
  • Pignatari M, Zinner E, Hoppe P, Jordan CJ, Gibson BK, Trappitsch R, Herwig F, Fryer C, Hirschi R, Timmes FX, Collaboration N, Network BRIDGCEUK. 2015. CARBON-RICH PRESOLAR GRAINS FROM MASSIVE STARS: SUBSOLAR C-12/C-13 AND N-14/N-15 RATIOS AND THE MYSTERY OF N-15. ASTROPHYSICAL JOURNAL LETTERS, vol. 808(2), Article ARTN L43. link> doi>
  • Jones S, Hirschi R, Pignatari M, Heger A, Georgy C, Nishimura N, Fryer C, Herwig F. 2015. Code dependencies of pre-supernova evolution and nucleosynthesis in massive stars: evolution to the end of core helium burning. MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, vol. 447(4), 3115-3129. link> doi>
  • Cescutti G, Romano D, Matteucci F, Chiappini C, Hirschi R. 2015. The role of neutron star mergers in the chemical evolution of the Galactic halo. ASTRONOMY & ASTROPHYSICS, vol. 577, Article ARTN A139. link> doi>
  • Whalen DJ, Smidt J, Heger A, Hirschi R, Yusof N, Even W, Fryer CL, Stiavelli M, Chen K-J, Joggerst CC. 2015. PAIR-INSTABILITY SUPERNOVAE IN THE LOCAL UNIVERSE (vol 9, 797, 2014). ASTROPHYSICAL JOURNAL, vol. 801(1), Article ARTN 71. link> doi>
  • Rauscher T, Travaglio C, Gallino R, Nishimura N, Hirschi R. Production of 92Nb, 92Mo, and 146Sm in the gamma-process in SNIa. link>
  • Jones S, Hirschi R, Nomoto K. 2014. THE FINAL FATE OF STARS THAT IGNITE NEON AND OXYGEN OFF-CENTER: ELECTRON CAPTURE OR IRON CORE-COLLAPSE SUPERNOVA?. ASTROPHYSICAL JOURNAL, vol. 797(2), Article ARTN 83. link> doi>
  • Whalen DJ, Smidt J, Heger A, Hirschi R, Yusof N, Even W, Fryer CL, Stiavelli M, Chen K-J, Joggerst CC. 2014. PAIR-INSTABILITY SUPERNOVAE IN THE LOCAL UNIVERSE. ASTROPHYSICAL JOURNAL, vol. 797(1), Article ARTN 9. link> doi>
  • Shingles LJ, Karakas AI, Hirschi R, Fishlock CK, Yong D, Da Costa GS, Marino AF. 2014. THE s-PROCESS ENRICHMENT OF THE GLOBULAR CLUSTERS M4 AND M22. ASTROPHYSICAL JOURNAL, vol. 795(1), Article ARTN 34. link> doi>
  • Cristini A, Hirschi R, Georgy C, Meakin C, Arnett D, Viallet M. Linking 1D Stellar Evolution to 3D Hydrodynamical Simulations. link> doi> link>
  • Barbuy B, Chiappini C, Cantelli E, Depagne E, Pignatari M, Hirschi R, Cescutti G, Ortolani S, Hill V, Zoccali M, Minniti D, Trevisan M, Bica E, Gomez A. 2014. High-resolution abundance analysis of red giants in the globular cluster NGC 6522. ASTRONOMY & ASTROPHYSICS, vol. 570, Article ARTN A76. link> doi>
  • Georgy C, Ekstroem S, Eggenberger P, Meynet G, Haemmerle L, Maeder A, Granada A, Groh JH, Hirschi R, Mowlavi N, Yusof N, Charbonnel C, Decressin T, Barblan F. 2013. Grids of stellar models with rotation III. Models from 0.8 to 120 M-circle dot at a metallicity Z=0.002. ASTRONOMY & ASTROPHYSICS, vol. 558, Article ARTN A103. link> doi>
  • Georgy C, Ekström S, Eggenberger P, Meynet G, Haemmerlé L, Maeder A, Granada A, Groh JH, Hirschi R, Mowlavi N, Yusof N, Charbonnel C, Decressin T, Barblan F. Grids of stellar models with rotation - III. Models from 0.8 to 120 Msun at a metallicity Z = 0.002. link> doi> link>
  • Jones S, Hirschi R, Nomoto K, Fischer T, Timmes FX, Herwig F, Paxton B, Toki H, Suzuki T, Martinez-Pinedo G, Lam YH, Bertolli MG. 2013. ADVANCED BURNING STAGES AND FATE OF 8-10 M-circle dot STARS. ASTROPHYSICAL JOURNAL, vol. 772(2), Article ARTN 150. link> doi>
  • Toki H, Suzuki T, Nomoto K, Jones S, Hirschi R. 2013. Detailed beta-transition rates for URCA nuclear pairs in 8-10 solar-mass stars. PHYSICAL REVIEW C, vol. 88(1), Article ARTN 015806. link> doi>
  • Pignatari M, Zinner E, Bertolli MG, Trappitsch R, Hoppe P, Rauscher T, Fryer C, Herwig F, Hirschi R, Timmes FX, Thielemann F-K, Collaboration N. 2013. SILICON CARBIDE GRAINS OF TYPE C PROVIDE EVIDENCE FOR THE PRODUCTION OF THE UNSTABLE ISOTOPE Si-32 IN SUPERNOVAE. ASTROPHYSICAL JOURNAL LETTERS, vol. 771(1), Article ARTN L7. link> doi>
  • Yusof N, Hirschi R, Meynet G, Crowther PA, Ekstrom S, Frischknecht U, Georgy C, Kassim HA, Schnurr O. Evolution and fate of very massive stars. link> doi> link>
  • Cescutti G, Chiappini C, Hirschi R, Meynet G, Frischknecht U. 2013. The s-process in the Galactic halo: the fifth signature of spinstars in the early Universe?. ASTRONOMY & ASTROPHYSICS, vol. 553, Article UNSP A51. link> doi>
  • Pignatari M, Wiescher M, Timmes FX, de Boer RJ, Thielemann F-K, Fryer C, Heger A, Herwig F, Hirschi R, Collaboration N. 2013. PRODUCTION OF CARBON-RICH PRESOLAR GRAINS FROM MASSIVE STARS. ASTROPHYSICAL JOURNAL LETTERS, vol. 767(2), Article ARTN L22. link> doi>
  • Pignatari M, Hirschi R, Wiescher M, Gallino R, Bennett M, Beard M, Fryer C, Herwig F, Rockefeller G, Timmes FX, Collaboration N. 2013. THE C-12+C-12 REACTION AND THE IMPACT ON NUCLEOSYNTHESIS IN MASSIVE STARS. ASTROPHYSICAL JOURNAL, vol. 762(1), Article ARTN 31. link> doi>
  • Muijres L, Vink JS, de Koter A, Hirschi R, Langer N, Yoon S-C. 2012. Mass-loss predictions for evolved very metal-poor massive stars. ASTRONOMY & ASTROPHYSICS, vol. 546, Article ARTN A42. link> doi>
  • Georgy C, Ekstroem S, Meynet G, Massey P, Levesque EM, Hirschi R, Eggenberger P, Maeder A. 2012. Grids of stellar models with rotation II. WR populations and supernovae/GRB progenitors at Z=0.014. ASTRONOMY & ASTROPHYSICS, vol. 542, Article ARTN A29. link> doi>
  • Massimi C, Koehler P, Bisterzo S, Colonna N, Gallino R, Gunsing F, Kaeppeler F, Lorusso G, Mengoni A, Pignatari M, Vannini G, Abbondanno U, Aerts G, Alvarez H, Alvarez-Velarde F, Andriamonje S, Andrzejewski J, Assimakopoulos P, Audouin L, Badurek G, Barbagallo M, Baumann P, Becvar F, Belloni F, Bennett M, Berthoumieux E, Calviani M, Calvino F, Cano-Ott D, Capote R, Carrapico C, Carrillo de Albornoz A, Cennini P, Chepel V, Chiaveri E, Cortes G, Couture A, Cox J, Dahlfors M, David S, Dillmann I, Dolfini R, Domingo-Pardo C, Dridi W, Duran I, Eleftheriadis C, Embid-Segura M, Ferrant L, Ferrari A, Ferreira-Marques R, Fitzpatrick L, Frais-Koelbl H, Fujii K, Furman W, Goncalves I, Gonzalez-Romero E, Goverdovski A, Gramegna F, Griesmayer E, Guerrero C, Haas B, Haight R, Heil M, Herrera-Martinez A, Herwig F, Hirschi R, Igashira M, Isaev S, Jericha E, Kadi Y, Karadimos D, Karamanis D, Kerveno M, Ketlerov V, Konovalov V, Kopecky S, Kossionides E, Krticka M, Lampoudis C, Leeb H, Lederer C, Lindote A, Lopes I, Losito R, Lozano M, Lukic S, Marganiec J, Marques L, Marrone S, Martinez T, Mastinu P, Mendoza E, Milazzo PM, Moreau C, Mosconi M, Neves F, Oberhummer H, O'Brien S, Oshima M, Pancin J, Papachristodoulou C, Papadopoulos C, Paradela C, Patronis N, Pavlik A, Pavlopoulos P, Perrot L, Pigni MT, Plag R, Plompen A, Plukis A, Poch A, Praena J, Pretel C, Quesada J, Rauscher T, Reifarth R, Rockefeller G, Rosetti M, Rubbia C, Rudolf G, Salgado J, Santos C, Sarchiapone L, Sarmento R, Savvidis I, Stephan C, Tagliente G, Tain JL, Tarrio D, Tassan-Got L, Tavora L, Terlizzi R, Vaz P, Ventura A, Villamarin D, Vlachoudis V, Vlastou R, Voss F, Walter S, Wendler H, Wiescher M, Wisshak K, Collaboration NTOF. 2012. Resonance neutron-capture cross sections of stable magnesium isotopes and their astrophysical implications. PHYSICAL REVIEW C, vol. 85(4), Article ARTN 044615. link> doi>
  • Bennett ME, Hirschi R, Pignatari M, Diehl S, Fryer C, Herwig F, Hungerford A, Nomoto K, Rockefeller G, Timmes FX, Wiescher M. 2012. The effect of C-12+C-12 rate uncertainties on the evolution and nucleosynthesis of massive stars. MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, vol. 420(4), 3047-3070. link> doi>
  • Frischknecht U, Hirschi R, Thielemann F-K. 2012. Non-standard s-process in low metallicity massive rotating stars. ASTRONOMY & ASTROPHYSICS, vol. 538, Article ARTN L2. link> doi>
  • Ekstroem S, Georgy C, Eggenberger P, Meynet G, Mowlavi N, Wyttenbach A, Granada A, Decressin T, Hirschi R, Frischknecht U, Charbonnel C, Maeder A. 2012. Grids of stellar models with rotation I. Models from 0.8 to 120 M-circle dot at solar metallicity (Z=0.014). ASTRONOMY & ASTROPHYSICS, vol. 537, Article ARTN A146. link> doi>
  • Suda T, Hirschi R, Fujimoto MY. 2011. STELLAR EVOLUTION CONSTRAINTS ON THE TRIPLE-alpha REACTION RATE. ASTROPHYSICAL JOURNAL, vol. 741(1), Article ARTN 61. link> doi>
  • Chiappini C, Frischknecht U, Meynet G, Hirschi R, Barbuy B, Pignatari M, Decressin T, Maeder A. 2011. Imprints of fast-rotating massive stars in the Galactic Bulge. NATURE, vol. 472(7344), 454-457. link> doi>
  • Herwig F, Pignatari M, Woodward PR, Porter DH, Rockefeller G, Fryer CL, Bennett M, Hirschi R. 2011. CONVECTIVE-REACTIVE PROTON-C-12 COMBUSTION IN SAKURAI'S OBJECT (V4334 SAGITTARII) AND IMPLICATIONS FOR THE EVOLUTION AND YIELDS FROM THE FIRST GENERATIONS OF STARS. ASTROPHYSICAL JOURNAL, vol. 727(2), Article ARTN 89. link> doi>
  • Meynet G, Georgy C, Hirschi R, Maeder A, Massey P, Przybilla N, Nieva M-F. Red Supergiants, Luminous Blue Variables and Wolf-Rayet stars: the single massive star perspective. Societe Royale des Sciences de Liege, Bulletin, vol. 80, p. 266-278 (Proceedings of the 39th Liege Astrophysical Colloquium, held in Li\`ege 12-16 July 2010, edited by G. Rauw, M. De Becker, Y. Naz\'e, J.-M. Vreux, P. Williams). link>
  • Frischknecht U, Hirschi R, Meynet G, Ekstroem S, Georgy C, Rauscher T, Winteler C, Thielemann F-K. 2010. Constraints on rotational mixing from surface evolution of light elements in massive stars. ASTRONOMY & ASTROPHYSICS, vol. 522, Article ARTN A39. link> doi>
  • Crowther PA, Schnurr O, Hirschi R, Yusof N, Parker RJ, Goodwin SP, Abu Kassim H. 2010. The R136 star cluster hosts several stars whose individual masses greatly exceed the accepted 150 M-circle dot stellar mass limit. MONTHLY NOTICES OF THE ROYAL ASTRONOMICAL SOCIETY, vol. 408(2), 731-751. link> doi>
  • Meynet G, Hirschi R, Ekstrom S, Maeder A, Georgy C, Eggenberger P, Chiappini C. 2010. Are C-rich ultra iron-poor stars also He-rich?. ASTRONOMY & ASTROPHYSICS, vol. 521, Article ARTN A30. link> doi>
  • Hirschi R and Maeder A. 2010. The GSF instability and turbulence do not account for the relatively low rotation rate of pulsars. ASTRONOMY & ASTROPHYSICS, vol. 519, Article ARTN A16. link> doi>
  • Abu Kassim H, Yusof N, Hirschi R, Eggenberger P. 2010. Effects of new nuclear reaction rates on the solar neutrino fluxes. ASTROPHYSICS AND SPACE SCIENCE, vol. 328(1-2), 163-166. link> doi>
  • Meynet G, Hirschi R, Ekstrom S, Maeder A, Georgy C, Eggenberger P, Chiappini C. Origin of CEMP stars: What helium and lithium can tell us about CEMP stars?. link> doi> link>
  • Pignatari M, Gallino R, Meynet G, Hirschi R, Herwig F, Wiescher M. 2008. THE s-PROCESS IN MASSIVE STARS AT LOW METALLICITY: THE EFFECT OF PRIMARY N-14 FROM FAST ROTATING STARS. ASTROPHYSICAL JOURNAL LETTERS, vol. 687(2), L95-L98. link> doi>
  • Ekstroem S, Meynet G, Chiappini C, Hirschi R, Maeder A. 2008. Effects of rotation on the evolution of primordial stars. ASTRONOMY & ASTROPHYSICS, vol. 489(2), 685-698. link> doi>
  • Eggenberger P, Meynet G, Maeder A, Hirschi R, Charbonnel C, Talon S, Ekstroem S. 2008. The Geneva stellar evolution code. ASTROPHYSICS AND SPACE SCIENCE, vol. 316(1-4), 43-54. link> doi>
  • Hirschi R, Chiappini C, Meynet G, Maeder A, Ekstrom S. 2008. Stellar Evolution at Low Metallicity. Proceedings of the International Astronomical Union. link> doi> link>
  • Meynet G, Ekstrom S, Maeder A, Hirschi R, Georgy C, Beffa C. Developments in physics of massive stars. link> doi> link>
  • Chiappini C, Ekstroem S, Meynet G, Hirschi R, Maeder A, Charbonnel C. 2008. A new imprint of fast rotators: low C-12/C-13 ratios in extremely metal-poor halo stars. ASTRONOMY & ASTROPHYSICS, vol. 479(1), L9-L12. link> doi>
  • Maeder A, Meynet G, Ekstrom S, Hirschi R, Georgy C. Massive Stars as Cosmic Engines through the Ages. link> doi> link>
  • HIRSCHI R. 2007. Very low-metallicity massive stars: Pre-SN evolution models and primary nitrogen production. Astronomy and Astrophysics, vol. 461(2), 571-583. doi>
  • Chiappini C, Hirschi R, Meynet G, Ekström S, Maeder A, Matteucci F. 2006. A strong case for fast stellar rotation at very low metallicities. Astronomy and Astrophysics. link> doi> link>
  • HIRSCHI R, Maeder A, Meynet G. 2005. Stellar evolution with rotation:XIII. Predicted GRB rates at various Z. Astronomy and Astrophysics, vol. 443(2), 581-591. doi>
  • HIRSCHI R, Maeder A, Meynet G. 2005. Yields of rotating stars at solar metallicity. Astronomy and Astrophysics, vol. 433, 1013-1022. doi>
  • HIRSCHI R, Meynet G, Maeder A. 2004. Stellar evolution with rotation. XII, Pre-supernova models. Astronomy and Astrophysics, vol. 425(2), 649-670. doi>
  • Magkotsios G, Timmes FX, Wiescher M, Fryer CL, Hungerford A, Young P, Bennett M, Diehl S, Herwig F, Hirschi R, Pignatari M, Rockefeller G. 44Ti and 56Ni in core-collapse supernovae. link>
  • Pignatari M, Herwig F, Bennett M, Diehl S, Fryer CL, Hirschi R, Hungerford A, Magkotsios G, Rockefeller G, Timmes FX, Young P. Complete nucleosynthesis calculations for low-mass stars from NuGrid. link>
  • Hungerford A, Fryer CL, Timmes FX, Young P, Bennett M, Diehl S, Herwig F, Hirschi R, Pignatari M, Magkotsios G, Rockefeller G. Difficulties in Probing Nuclear Physics: A Study of $^{44}$Ti and $^{56}$Ni. link>
  • Fryer CL, Young P, Bennett M, Diehl S, Herwig F, Hirschi R, Hungerford A, Pignatari M, Magkotsios G, Rockefeller G, Timmes FX. Nucleosynthesis Calculations from Core-Collapse Supernovae. link>
  • Herwig F, Bennett M, Diehl S, Fryer CL, Hirschi R, Hungerford A, Magkotsios G, Pignatari M, Rockefeller G, Timmes FX, Young P. Nucleosynthesis simulations for a wide range of nuclear production sites from NuGrid. link>
  • Rockefeller G, Fryer CL, Young P, Bennett M, Diehl S, Herwig F, Hirschi R, Hungerford A, Pignatari M, Magkotsios G, Timmes FX. Nucleosynthetic Yields from "Collapsars". link>
  • Hirschi R, Frischknecht U, Thielemann F-K, Pignatari M, Bennett M, Diehl S, Fryer CL, Herwig F, Hungerford A, Magkotsios G, Rockefeller G, Timmes FX, Young P. NuGrid: s process in massive stars. link>
  • Diehl S, Fryer CL, Hungerford A, Rockefeller G, Bennett M, Herwig F, Hirschi R, Pignatari M, Magkotsios G, Timmes FX, Young P, Clayton GC, Motl P, Tohline JE. NuGrid: Toward High Precision Double-Degenerate Merger Simulations with SPH in 3D. link>
  • Young P, Ellinger CI, Timmes FX, Arnett D, Fryer CL, Rockefeller G, Hungerford A, Diehl S, Bennett M, Hirschi R, Pignatari M, Herwig F, Magkotsios G. Spatial Distribution of Nucleosynthesis Products in Cassiopeia A: Comparison Between Observations and 3D Explosion Models. link>
  • Chiappini C, Hirschi R, Matteucci F, Meynet G, Ekstrom S, Maeder A. The impact of stellar rotation on the CNO abundance patterns in the Milky Way at low metallicities. PoSNIC-IX:080,2006. link>
  • Crowther PA, Hirschi R, Walborn NR, Yusof N. 2012. Very Massive Stars and the Eddington Limit. FOUR DECADES OF RESEARCH ON MASSIVE STARS, vol. 465, 196-+. link>
  • Georgy C, Ekström S, Hirschi R, Meynet G, Groh J, Eggenberger P. Wolf-Rayet stars as an evolved stage of stellar life. link>

Chapters

  • Hirschi R. 2014. Evolution and Nucleosynthesis of Very Massive Stars. In Very Massive Stars in the Local Universe. Vink JS (Ed.). (vol. 412). Switzerland: Springer. doi>

Other

  • Choplin A, Meynet G, Maeder A, Hirschi R, Ekstrom S, Chiappini C. 2016. Clues on the first stars from CEMP-no stars. Proceedings of the International Astronomical Union (vol. 11, pp. 282-283). Cambridge University Press. doi>
  • Rauscher T, Nishimura N, Hirschi R. 2016. Theory Considerations For Nucleosynthesis Beyond Fe With Special Emphasis On p-Nuclei In Massive Stars. CETUP 2015 - WORKSHOP ON DARK MATTER, NEUTRINO PHYSICS AND ASTROPHYSICS & PPC 2015 - IXTH INTERNATIONAL CONFERENCE ON INTERCONNECTIONS BETWEEN PARTICLE PHYSICS AND COSMOLOGY (vol. 1743). link> doi>
  • Lam YH, Martinez-Pinedo G, Langanke K, Jones S, Hirschi R, Zegers RGT, Brown BA. 2014. Electron Capture and Beta-Decay Rates for the Collapse of O plus Ne plus Mg Cores. INPC 2013 - INTERNATIONAL NUCLEAR PHYSICS CONFERENCE, VOL. 2 (vol. 66). link> doi>
  • Nishimura N, Hirschi R, Pignatari M, Herwig F, Beard M, Imbriani G, Goerres J, deBoer RJ, Wiescher M. 2014. Impact of the uncertainty in alpha-captures on Ne-22 on the weak s-process in massive stars. ORIGIN OF MATTER AND EVOLUTION OF GALAXIES 2013 (vol. 1594, pp. 146-151). link> doi>
  • Yusof N, Hirschi R, Abu Kassim H. 2012. Fate of most massive stars. DEATH OF MASSIVE STARS: SUPERNOVAE AND GAMMA-RAY BURSTS (pp. 431-432). link> doi>
  • Jones S, Hirschi R, Herwig F, Paxton B, Timmes FX, Nomoto K. 2012. Progenitors of electron-capture supernovae. DEATH OF MASSIVE STARS: SUPERNOVAE AND GAMMA-RAY BURSTS (pp. 341-342). link> doi>
  • Suda T, Hirschi R, Fujimoto MY. 2012. Triple-alpha Reaction Rate Constrained by Stellar Evolution Models. ORIGIN OF MATTER AND EVOLUTION OF GALAXIES 2011 (vol. 1484, pp. 263-268). link> doi>
  • Frischknecht U, Hirschi R, Meynet G, Ekstroem S, Georgy C, Rauscher T, Winteler C, Thielemann F-K. 2010. Boron depletion in 9 to 15 M-circle dot stars with rotation. LIGHT ELEMENTS IN THE UNIVERSE (pp. 421-+). link> doi>
  • Suda T, Hirschi R, Fujimoto MY. 2010. ni The Effect of the Triple-alpha Reaction Rate on Stellar Evolution at Low-Metallicity. TOURS SYMPOSIUM ON NUCLEAR PHYSICS AND ASTROPHYSICS - VII (vol. 1238, pp. 122-+). link> doi>
  • Meynet G, Hirschi R, Ekstrom S, Maeder A, Georgy C, Eggenberger P, Chiappini C. 2010. Nucleosynthesis in Rotating massive stars and Abundances in the Early Galaxy. CHEMICAL ABUNDANCES IN THE UNIVERSE: CONNECTING FIRST STARS TO PLANETS (pp. 98-+). link> doi>
  • Hirschi R, Meynet G, Maeder A, Ekstroem S, Georgy C. 2010. Stellar Evolution in the Upper HR Diagram. HOT AND COOL: BRIDGING GAPS IN MASSIVE-STAR EVOLUTION (vol. 425, pp. 13-+). link>
  • Bennett ME, Hirschi R, Pignatari M, Diehl S, Fryer C, Herwig F, Hungerford A, Magkotsios G, Rockefeller G, Timmes F, Wiescher M, Young P. 2010. The effect of C-12+C-12 rate uncertainties on s-process yields. NUCLEAR PHYSICS IN ASTROPHYSICS IV (NPAIV 2009) (vol. 202). link> doi>
  • Ekstroem S, Meynet G, Maeder A, Chiappini C, Georgy C, Hirschi R. 2010. Theoretical stellar Delta Y/Delta O in the early Universe. LIGHT ELEMENTS IN THE UNIVERSE (pp. 447-+). link>
  • Meynet G, Hirschi R, Ekstrom S, Maeder A, Georgy C, Eggenberger P, Chiappini C. 2010. What helium and lithium can tell us about CEMP stars?. LIGHT ELEMENTS IN THE UNIVERSE (pp. 141-+). link> doi>
  • Meynet G, Chiappini C, Georgy C, Pignatari M, Hirschi R, Ekstroem S, Maeder A. 2009. Evolution and chemical and dynamical effects of high-mass stars. GALAXY DISK IN COSMOLOGICAL CONTEXT, PROCEEDINGS OF THE 254TH SYMPOSIUM OF THE IAU (pp. 325-+). link> doi>
  • Chiappini C, Ekstroem S, Meynet G, Hirschi R, Maeder A. 2009. HUNTING FOR THE IMPRINTS OF THE FIRST STARS. XII IAU REGIONAL LATIN AMERICAN MEETING (vol. 35, pp. 207-+). link>
  • Hirschi R, Ekstroem S, Georgy C, Meynet G, Maeder A. 2009. Stellar evolution models at the Magellanic Cloud metallicities. MAGELLANIC SYSTEM: STARS, GAS, AND GALAXIES (pp. 337-+). link> doi>
  • Meynet G, Ekstroem S, Georgy C, Maeder A, Hirschi R. 2008. Massive star evolution: from the early to the present day Universe. ART OF MODELLING STARS IN THE 21ST CENTURY (pp. 317-+). link> doi>
  • Ekstroem S, Meynet G, Hirschi R, Maeder A. 2008. Powerful explosions at Z=0?. LOW-METALLICITY STAR FORMATION: FROM THE FIRST STARS TO DWARF GALAXIES (pp. 194-198). link> doi>
  • Meynet G, Ekstroem S, Maeder A, Hirschi R, Chiappini C, Georgy C. 2008. SPINSTARS at low metallicities. FIRST STARS III (vol. 990, pp. 212-+). link> doi>
  • Hirschi R, Frischknecht U, Thielemann F-K, Pignatari M, Chiappini C, Ekstroem S, Meynet G, Maeder A. 2008. Stellar Evolution in the Early Universe. LOW-METALLICITY STAR FORMATION: FROM THE FIRST STARS TO DWARF GALAXIES (pp. 297-+). link> doi>
  • Chiappini C, Ekstroem S, Meynet G, Maeder A, Hirschi R. 2008. Were the first stars fast rotators?. FIRST STARS III (vol. 990, pp. 325-+). link>
  • Hirschi R, Maeder A, Meynet G, Chiappini C, Ekstroem S. 2007. Evolution of the first stellar generations. CRAL-2006 CHEMODYNAMICS: FROM FIRST STARS TO LOCAL GALAXIES (vol. 24, pp. 263-+). link> doi>
  • Hirschi R, Chiappini C, Meynet G, Ekstrom S, Maeder A. 2007. Mass loss and very low-metallicity stars. UNSOLVED PROBLEMS IN STELLAR PHYSICS (vol. 948, pp. 397-404). link>
  • Thielemann F-K, Froehlich C, Hirschi R, Liebendoerfer M, Dillmann I, Mocelj D, Rauscher T, Martinez-Pinedo G, Langanke K, Farouqi K, Kratz K-L, Pfeiffer B, Panov I, Nadyozhin DK, Blinnikov S, Bravo E, Hix WR, Hoflich P, Zinner NT. 2007. Production of intermediate-mass and heavy nuclei. PROGRESS IN PARTICLE AND NUCLEAR PHYSICS VOL 59, NO 1 (vol. 59, pp. 74-93). link> doi>
  • Hirschi R, Meynet G, Maeder A. 2006. GRB progenitors at low metallicities. NUOVO CIMENTO DELLA SOCIETA ITALIANA DI FISICA B-GENERAL PHYSICS RELATIVITY ASTRONOMY AND MATHEMATICAL PHYSICS AND METHODS (vol. 121, pp. 1183-1187). link> doi>
  • Meynet G, Hirschi R, Ekstrom S, Maeder A. 2006. Evolution of rotating stars at very low metallicity. Stellar Evolution at Low Metallicity: Mass Loss, Explosions, Cosmology (vol. 353, pp. 49-62). link>
  • Meynet G, Hirschi R, Maeder A, Ekstroem S. 2006. Nucleosynthesis from massive rotating stars. STARS AND NUCLEI: A TRIBUTE TO MANUEL FORESTINI (vol. 19, pp. 85-+). link> doi>
  • Hirschi R. 2006. Rotating massive stars @ very low Z: High C & N production. Origin of Matter and Evolution of Galaxies (vol. 847, pp. 71-76). link>
  • Maeder A, Meynet G, Hirschi R, Ekstroem S. 2006. Rotational mixing in massive stars and its many consequences. CHEMICAL ABUNDANCES AND MIXING IN STARS IN THE MILKY WAY AND ITS SATELLITES (pp. 308-313). link> doi>
  • Hirschi R and al E. 2006. Stellar evolution of massive stars at very low metallicities (With 10 Figures). In S. Roeser (Ed.). Reviews in Modern Astronomy (vol. 19, p. 101-+).
  • Hirschi R, Meynet G, Maeder A. 2005. Rotating massive stars: Pre-SN models and stellar yields at solar metallicity. NUCLEAR PHYSICS A (vol. 758, pp. 234C-237C). link> doi>
  • Thielemann FK, Argast D, Brachwitz F, Fisker JL, Frohlich C, Hirschi R, Kolbe E, Mocelj D, Rauscher T. 2005. Nuclear physics: A key ingredient in astrophysical modeling. NUCLEAR PHYSICS A (vol. 751, pp. 301C-326C). link> doi>
  • Maeder A, Meynet G, Hirschi R. 2005. Chemical abundances and yields from massive stars. Cosmic Abundances as Records of Stellar Evolution and Nucleosynthesis in Honor of David L. Lambert (vol. 336, pp. 79-92). link>
  • Meynet G, Hirschi R, Maeder A. 2005. Effects of rotation on pre-supernova models. 1604-2004: Supernovae as Cosmological Lighthouses (vol. 342, pp. 99-104). link>
  • Maeder A, Meynet G, Hirschi R. 2005. Evolution of the most massive stars. Fate of the Most Massive Stars, Proceedings (vol. 332, pp. 3-13). link>
  • Hirschi R, Meynet G, Maeder A. 2005. Massive rotating stars: Pre-supernova evolution at solar metallicity. 1604-2004: Supernovae as Cosmological Lighthouses (vol. 342, pp. 131-132). link>
  • Hirschi R, Meynet G, Maeder A, Goriely S. 2005. Pre-supernova evolution of rotating massive stars. COSMIC EXPLOSIONS (vol. 99, pp. 209-213). link>
  • Hirschi R, Maeder A, Meynet G. 2004. Dynamical shear instability. STELLAR ROTATION (pp. 510-511). link>
  • Meynet G, Hirschi R, Maeder A. 2004. Mixing and rotation. FUTURE ASTRONUCLEAR PHYSICS: FROM MICROSCOPIC PUZZLES TO MACROSCOPIC NIGHTMARES (vol. 11, pp. 77-96). link> doi>
  • Meynet G, Maeder A, Hirschi R. 2003. Stellar yields in CNO from rotating stellar models. CNO IN THE UNIVERSE (vol. 304, pp. 293-301). link>

Current/past Undergraduate modules taught:

- Electricty and Magnetism (PHY-10021/23)

- Nature of Matter (PHY-10024)

- Nuclear and Particle Physics (PHY-20009)

- Physics of Fluids (PHY30030)

  • SASP lectures on "Molecular Theory" and "Quantum and Astrophysics