相关论文: Telescopes versus Microscopes: the puzzle of Iron-…
Chondritic meteorites constitute the most ancient rock record available in the laboratory to study the formation of the solar system and its planets. Detailed investigations of their mineralogy, petrography, chemistry and isotopic…
The transition between the nearly smooth initial state of the Universe and its clumpy state today occurred during the epoch when the first stars and low-luminosity quasars formed. For Cold Dark Matter cosmologies, the radiation produced by…
With the exception of the Big Bang, responsible for 1,2H, 3,4He, and 7Li, stars act as sources for the composition of the interstellar medium. Cosmic rays are related to the latter and very probably due to acceleration of the mixed…
Massive stars, which terminate their evolution as core collapse supernovae, are theoretically predicted to eject more than 1E-5 solar masses of the radioisotope 60Fe. If such an event occurs sufficiently close to our solar system, traces of…
The origin of the Universe and its material content remains one of the most fundamental questions in science. Gamma-ray bursts (GRBs), with their extreme luminosities and high-redshift detectability, provide a unique window into the history…
Stellar and supernova nucleosynthesis in the first few billion years of the cosmic history have set the scene for early structure formation in the Universe, while little is known about their nature. Making use of stellar physical parameters…
The external pollution of the first stars in the Galaxy is investigated. The first stars were born in clouds composed of the pristine gas without heavy elements. These stars accreted gas polluted with heavy elements while they still…
Approximately 2.8 Myr before the present our planet was subjected to the debris of a supernova explosion. The terrestrial proxy for this event was the discovery of live atoms of 60Fe in a deep-sea ferromanganese crust. The signature for…
It is now recognized that long-duration Gamma-Ray Bursts (GRBs) are linked to the collapse of massive stars, based on the association between (low-redshift) GRBs and (type Ic) core-collapse supernovae (SNe). The census of massive stars and…
Anomalies among the daughter nuclei of the extinct short-lived radionuclides (SLRs) in the calcium-aluminum-rich inclusions (CAIs) indicate that the Solar System must have been born near a source of the SLRs so that they could be…
Modern cosmological simulations predict that the first generation of stars formed with a mass scale around 100 solar masses about 300-400 million years after the Big Bang. When the first stars reached the end of their lives, many of them…
The metal abundance of the hot plasma that permeates galaxy clusters represents the accumulation of heavy elements produced by billions of supernovae. Therefore, X-ray spectroscopy of the intracluster medium provides an opportunity to…
Planetary materials show systematic variations in their nucleosynthetic isotope compositions that resonate with orbital distance. The origin of this pattern remains debated, limiting how these isotopic signatures can be used to trace the…
The origin and fate of the most extended extragalactic neutral cloud known in the local Universe, the Leo ring, is still debated 38 years after its discovery. Its existence is alternatively attributed to leftover primordial gas with some…
The stellar origin of gamma-ray bursts can be explained by the rapid release of energy in a highly collimated, extremely relativistic jet. This in turn appears to require a rapidly spinning highly magnetised stellar core that collapses into…
We present our recent work on the conditions under which star formation occurs in a metal-poor environment, the Large Magellanic Cloud ([Fe/H] ~ -0.4). Water masers are used as beacons of the current star formation in HII regions. Comparing…
The formation of massive stars is one of the major unsolved problems in stellar astrophysics. However, only few if any of these are found as single stars, on average massive stars have more than one companion. Many of them are born in dense…
The mean iron abundance observed in the intergalactic medium (IGM) within galaxy clusters and without galaxy clusters is consistent with the mean amount of iron per unit volume in the Universe which has been produced by standard supernova…
We present measurements of carbon, oxygen, silicon, and iron in quasar absorption systems existing when the universe was roughly one billion years old. We measure column densities in nine low-ionization systems at 4.7 < z < 6.3 using Keck,…
To understand the formation of stellar groups, one must first document carefully the birth pattern within real clusters and associations. In this study of Taurus-Auriga, we combine pre-main-sequence ages from our own evolutionary tracks…