Detailed homogeneous elemental abundance estimates by GALAH DR3 are compared with supernova yield models of Pop~III (zero-metal) core-collapse supernovae (CCSNe), normal (non-zero-metal) CCSNe, and Type Ia supernovae (SN Ia) to examine which of the individual yields or their combinations best reproduce the observed elemental abundance patterns for each of the old halo stars ("OHS"). Making use of stellar physical parameters measured by GALAH Data Release 3 with accurate astrometry from the Gaia EDR3, we have selected $\sim 100$ old main-sequence turn-off stars (ages $\gtrsim 12$ Gyrs) with kinematics compatible with the Milky Way stellar halo population in the Solar neighborhood. 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. These results provide an insight into the birth environments of the oldest stars in the Galactic halo.
The results suggest that, in the progenitor systems of the OHS with > −1.5, ∼ 50–60 per cent of Fe mass originated from normal CCSNe at the earliest phases of the Milky Way formation. We find that the observed abundances in the OHS with > −1.5 are best explained by contributions from both CCSNe and SN Ia, where the fraction of SN Ia among all the metal-enriching SNe is up to 10–20 per cent for stars with high ratios and up to 20–27 per cent for stars with low ratios, depending on the assumption about the relative fraction of near-Chandrasekhar-mass SNe Ia progenitors. Detailed homogeneous elemental abundance estimates by GALAH DR3 are compared with supernova yield models of Pop III (zero-metal) core-collapse supernovae (CCSNe), normal (non-zero-metal) CCSNe, and Type Ia supernovae (SN Ia) to examine which of the individual yields or their combinations best reproduce the observed elemental abundance patterns for each of the old halo stars (“OHS”). Making use of stellar physical parameters measured by GALAH Data Release 3 with accurate astrometry from the Gaia EDR3, we have selected ∼100 old main-sequence turn-off stars (ages ≳ 12 Gyrs) with kinematics compatible with the Milky Way stellar halo population in the Solar neighborhood. Kinematic analysis shows that the objects HE 0110$-$0406 and HE1447$+$0102 are thick disk objects and the remaining five objects belong to the halo population of the Galaxy. Of pristine interstellar medium are He-rich (helium mass fraction between 0.30Īnd 0.60), Li-depleted and present low $^$C ratios we have examined if any internal mixing had modified their surface chemical compositions.
Rotating and non-rotating models are considered.ĬRUMP stars formed from wind material of massive stars mixed with small amounts
#Starmade rotate block plus
Stars, with wind plus supernova ejecta and with material extracted from theĮnvelope of early AGB stars. Made of interstellar medium mixed with wind material of very metal poor massive We discuss the chemical composition of stars Having CRUMP stars which are He-rich, i.e. Signatures allowing to discriminate among models.
We deduce some expected trends based on nucleosynthetic arguments and look for To explain the peculiar abundances observed at the surface of the CRUMP stars. We propose a synthetic view of the different models so far proposed The origin of their peculiar surface abundances is not 5.96, -5.4 and -4.75) are carbon-rich, they are called C-Rich Ultra-Metal Poor (abridged) The three most iron poor stars presently known ( equal to
0 kommentar(er)
