Outputs (104)

THE12C +12C REACTION AND THE IMPACT ON NUCLEOSYNTHESIS IN MASSIVE STARS (2012)
Journal Article
Pignatari, M., Hirschi, R., Wiescher, M., Gallino, R., Bennett, M., Beard, M., …Timmes, F. X. (2013). THE12C +12C REACTION AND THE IMPACT ON NUCLEOSYNTHESIS IN MASSIVE STARS. Astrophysical Journal, 762(1), 31. https://doi.org/10.1088/0004-637x/762/1/31

Despite much effort in the past decades, the C-burning reaction rate is uncertain by several orders of magnitude, and the relative strength between the different channels 12C(12C, α)20Ne, 12C(12C, p)23Na, and 12C(12C, n)23Mg is poorly determined. Add... Read More about THE12C +12C REACTION AND THE IMPACT ON NUCLEOSYNTHESIS IN MASSIVE STARS.

Red Supergiants, Luminous Blue Variables and Wolf-Rayet stars: the single massive star perspective (2011)
Journal Article
Meynet, G., Georgy, C., Hirschi, R., Maeder, A., Massey, P., Przybilla, N., & Nieva, M. (2011). Red Supergiants, Luminous Blue Variables and Wolf-Rayet stars: the single massive star perspective. Bulletin de la Société Royale des Sciences de Liège, 80, 266-278

We discuss, in the context of the single star scenario, the nature of the progenitors of Red Supergiants (RSG), of Luminous Blue Variables (LBV) and of Wolf-Rayet (WR) stars. These three different populations correspond to evolved phases of Main Sequ... Read More about Red Supergiants, Luminous Blue Variables and Wolf-Rayet stars: the single massive star perspective.

Origin of CEMP stars: What helium and lithium can tell us about CEMP stars? (2010)
Journal Article
Meynet, G., Hirschi, R., Ekstrom, S., Maeder, A., Georgy, C., Eggenberger, P., & Chiappini, C. (2010). Origin of CEMP stars: What helium and lithium can tell us about CEMP stars?. Proceedings of the International Astronomical Union, 268, 141-146. https://doi.org/10.1017/S1743921310003984

We show that the peculiar surface abundance patterns of Carbon Enhanced Metal Poor (CEMP) stars has been inherited from material having been processed by H- and He-burning phases in a previous generation of stars (hereafter called the ``Source Stars'... Read More about Origin of CEMP stars: What helium and lithium can tell us about CEMP stars?.

Massive Stars as Cosmic Engines through the Ages (2008)
Journal Article
Hirschi, R. (2008). Massive Stars as Cosmic Engines through the Ages. Proceedings of the International Astronomical Union, 3-16. https://doi.org/10.1017/S1743921308020292

Some useful developments in the model physics are briefly presented, followed by model results on chemical enrichments and WR stars. We discuss the expected rotation velocities of WR stars. We emphasize that the (C+O)/He ratio is a better chemical in... Read More about Massive Stars as Cosmic Engines through the Ages.

Stellar Evolution in the Early Universe (2008)
Journal Article
Hirschi, R., Frischknecht, U., -K. Thielemann, F., Pignatari, M., Chiappini, C., Ekstroem, S., …Maeder, A. (2008). Stellar Evolution in the Early Universe. Proceedings of the International Astronomical Union, 4(S255), https://doi.org/10.1017/S1743921308024976

Massive stars played a key role in the early evolution of the Universe. They formed with the first halos and started the re-ionisation. It is therefore very important to understand their evolution. In this paper, we describe the strong impact of rota... Read More about Stellar Evolution in the Early Universe.

Stellar Evolution at Low Metallicity (2007)
Journal Article
Hirschi, R., Chiappini, C., Meynet, G., Maeder, A., & Ekstrom, S. (2007). Stellar Evolution at Low Metallicity. Proceedings of the International Astronomical Union, 3(S250), https://doi.org/10.1017/S1743921308020528

Massive stars played a key role in the early evolution of the Universe. They formed with the first halos and started the re-ionisation. It is therefore very important to understand their evolution. In this review, we first recall the effect of metall... Read More about Stellar Evolution at Low Metallicity.

Mass loss and very low-metallicity stars (2007)
Journal Article
Hirschi, R., Chiappini, C., Meynet, G., Ekstrom, S., & Maeder, A. (2007). Mass loss and very low-metallicity stars. AIP conference proceedings, 948, 397–404. https://doi.org/10.1063/1.2818999

Mass loss plays a dominant role in the evolution of massive stars at solar metallicity. After discussing different mass loss mechanisms and their metallicity dependence, we present the possibility of strong mass loss at very low metallicity. Our mode... Read More about Mass loss and very low-metallicity stars.

GRB progenitors at low metallicities (2007)
Journal Article
Hirschi, R., Meynet, G., & Maeder, A. (2007). GRB progenitors at low metallicities. IL NUOVO CIMENTO B, 10-11, 1183-1187. https://doi.org/10.1393/ncb/i2007-10237-6

We calculated pre-supernova evolution models of single rotating massive stars. These models reproduce observations during the early stages of the evolution very well, in particular Wolf--Rayet (WR) populations and ratio between type II and type Ib,c... Read More about GRB progenitors at low metallicities.

PopII 1/2 stars: very high N14 and low O16 yields (2005)
Journal Article
Hirschi, R. (2005). PopII 1/2 stars: very high N14 and low O16 yields. Proceedings of the International Astronomical Union, 1(S228), https://doi.org/10.1017/S1743921305005922

Nine 20 Mo models were computed with metallicities ranging from solar, through $Z=10^{-5}$ ([Fe/H]=~-3.1) down to $Z=10^{-8}$ ([Fe/H]=~-6.1) and with initial rotational velocities between 0 and 600 km/s to study the impact of initial metallicity and... Read More about PopII 1/2 stars: very high N14 and low O16 yields.

Stellar evolution with rotation XIII: Predicted GRB rates at various Z (2005)
Journal Article
Hirschi, R., Meynet, G., & Maeder, A. (2005). Stellar evolution with rotation XIII: Predicted GRB rates at various Z. Astronomy & Astrophysics, 443(2), https://doi.org/10.1051/0004-6361%3A20053329

We present the evolution of rotation in models of massive single stars covering a wide range of masses and metallicities. These models reproduce very well observations during the early stages of the evolution (in particular WR populations and ratio b... Read More about Stellar evolution with rotation XIII: Predicted GRB rates at various Z.