Retainment of r-process material in dwarf galaxies

Paz Beniamini, Irina Dvorkin, Joe Silk

Research output: Contribution to journalArticlepeer-review


The synthesis of r-process elements is known to involve extremely energetic explosions. At the same time, recent observations find significant r-process enrichment even in extremely small ultra-faint dwarf (UFD) galaxies. This raises the question of retainment of those elements within their hosts. We estimate the retainment fraction and find that it is large ~0.9, unless the r-process event is very energetic (≳1052 erg) and/or the host has lost a large fraction of its gas prior to the event. We estimate the r-process mass per event and rate as implied by abundances in UFDs, taking into account imperfect retainment and different models of UFD evolution. The results are consistent with previous estimates and with the constraints from the recently detected macronova accompanying a neutron star merger (GW170817). We also estimate the distribution of abundances predicted by thesemodels.We find that~0.07 of UFDs should have r-process enrichment. The results are consistent with both the mean values and the fluctuations of [Eu/Fe] in Galactic metal-poor stars, supporting the possibility that UFDs are the main 'building blocks' of the Galactic halo population.

Original languageEnglish
Pages (from-to)1994-2005
Number of pages12
JournalMonthly Notices of the Royal Astronomical Society
Issue number2
StatePublished - 1 Aug 2018
Externally publishedYes

Bibliographical note

Publisher Copyright:
© 2018 The Author(s). Published by Oxford University Press on behalf of the Royal Astronomical Society.


  • Galaxies: dwarf
  • Stars: abundances
  • Stars: neutron


Dive into the research topics of 'Retainment of r-process material in dwarf galaxies'. Together they form a unique fingerprint.

Cite this