SIMBAD references

2020ApJ...898..150E - Astrophys. J., 898, 150-150 (2020/August-1)

The r-process Alliance: first Magellan/MIKE release from the southern search for r-process-enhanced stars.

EZZEDDINE R., RASMUSSEN K., FREBEL A., CHITI A., HINOJISA K., PLACCO V.M., JI A.P., BEERS T.C., HANSEN T.T., ROEDERER I.U., SAKARI C.M. and MELENDEZ J.

Abstract (from CDS):

Extensive progress has recently been made in our understanding of heavy-element production via the r-process in the universe, specifically with the first observed neutron star binary merger (NSBM) event associated with the gravitational-wave signal detected by LIGO, GW170817. The chemical abundance patterns of metal-poor r-process-enhanced stars provide key evidence for the dominant site(s) of the r-process and whether NSBMs are sufficiently frequent or prolific r-process sources to be responsible for the majority of r-process material in the universe. We present atmospheric stellar parameters (using a nonlocal thermodynamic equilibrium analysis) and abundances from a detailed analysis of 141 metal-poor stars carried out as part of the R-Process Alliance (RPA) effort. We obtained high-resolution "snapshot" spectroscopy of the stars using the MIKE spectrograph on the 6.5 m Magellan Clay telescope at Las Campanas Observatory in Chile. We find 10 new highly enhanced r-II (with [Eu/Fe] > +1.0), 62 new moderately enhanced r-I (+0.3 < [Eu/Fe] <= +1.0), and 17 new limited-r ([Eu/Fe] < +0.3) stars. Among those, we find 17 new carbon-enhanced metal-poor (CEMP) stars, of which five are CEMP-no. We also identify one new s-process-enhanced ([Ba/Eu] > +0.5) and five new r/s (0.0 < [Ba/Eu] < +0.5) stars. In the process, we discover a new ultra-metal-poor (UMP) star at [Fe/H] = -4.02. One of the r-II stars shows a deficit in α and Fe-peak elements, typical of dwarf galaxy stars. Our search for r-process-enhanced stars by RPA efforts has already roughly doubled the known r-process sample.

Abstract Copyright: © 2020. The American Astronomical Society. All rights reserved.

Journal keyword(s): Population II stars - Chemical abundances - Stellar properties - Stellar types

VizieR on-line data: <Available at CDS (J/ApJ/898/150): table1.dat table2.dat table3.dat table4.dat table5.dat table6.dat>

Simbad objects: 144

goto Full paper

goto View the references in ADS

To bookmark this query, right click on this link: simbad:2020ApJ...898..150E and select 'bookmark this link' or equivalent in the popup menu