Cardiff University | Prifysgol Caerdydd ORCA
Online Research @ Cardiff 
WelshClear Cookie - decide language by browser settings

s-process enrichment of ultrafaint dwarf galaxies

Tarumi, Yuta, Suda, Takuma, van de Voort, Freeke, Inoue, Shigeki, Yoshida, Naoki and Frebel, Anna 2021. s-process enrichment of ultrafaint dwarf galaxies. Monthly Notices of the Royal Astronomical Society 505 (3) , pp. 3755-3766. 10.1093/mnras/stab1487

[img] PDF - Published Version
Download (4MB)

Abstract

We study the production of barium (Ba) and strontium (Sr) in ultrafaint dwarf (UFDs) galaxies. Both r- and s- processes produce these elements, and one can infer the contribution of the r-process from the characteristic r-process abundance pattern, whereas the s-process contribution remains largely unknown. We show that the current s-process yield from asymptotic giant branch (AGB) stars is not sufficient to explain the Ba and Sr abundances observed in UFDs. Production of these elements would need to be efficient from the beginning of star formation in the galaxies. The discrepancy of nearly or more than 1 dex is not reconciled even if we consider s-process in super-AGB stars. We consider a possible resolution by assuming rotating massive stars (RMSs) and electron-capture supernovae (ECSNe) as additional contributors. We find that the RMSs could be the origin of Ba in UFDs if ∼10 per cent of massive stars are rotating at 300 km s−1. As for ECSNe, we argue that their fraction is less than 2 per cent of core-collapse supernova. It narrows the progenitor mass-range to ≲0.1M⊙ at −3 ≲ [Fe/H] ≲ −2. We also explore another resolution by modifying the stellar initial mass function (IMF) in UFDs and find a top-light IMF model that reproduces the observed level of Ba-enrichment. Future observations that determine or tightly constrain the europium and nitrogen abundances are crucial to identify the origin of Ba and Sr in UFDs.

Item Type: Article
Date Type: Publication
Status: Published
Schools: Physics and Astronomy
Publisher: Royal Astronomical Society
ISSN: 0035-8711
Date of First Compliant Deposit: 26 July 2021
Date of Acceptance: 20 May 2021
Last Modified: 02 Aug 2021 09:08
URI: http://orca.cardiff.ac.uk/id/eprint/142910

Actions (repository staff only)

Edit Item Edit Item

Downloads

Downloads per month over past year

View more statistics