English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Recent studies show that the majority of blue straggler stars (BSSs) in oldopen clusters are formed through mass transfer from an evolved star onto amain-sequence companion, resulting in a BSS and white dwarf (WD) in a binarysystem. We present constraints on the mass transfer histories of two BSS-WDbinaries in the open cluster NGC 188, using WD temperatures and surfacegravities measured with HST COS far-ultraviolet spectroscopy. Adopting aGaia-based cluster distance of $1847\pm107$ pc, we determine that one system,WOCS 4540, formed through Case C mass transfer resulting in a CO-core whitedwarf with $T_{\text{eff}}=17000^{+140}_{-200}$ K and a $\logg=7.80^{+0.06}_{-0.06}$, corresponding to a mass of $0.53^{+0.03}_{-0.03}$$M_{\odot}$ and a cooling age of $105^{+6}_{-5}$ Myr. The other system, WOCS5379, formed through Case B mass transfer resulting in a He-core white dwarfwith $T_{\text{eff}}=15500^{+170}_{-150}$ K and a $\logg=7.50^{+0.06}_{-0.05}$, corresponding to a mass of $0.42^{+0.02}_{-0.02}$$M_{\odot}$ and an age of $250^{+20}_{-20}$ Myr. The WD parameters areconsistent across four different cluster distance assumptions. We determinepossible progenitor binary systems with a grid of accretion models using MESA,and investigate whether these systems would lead to stable or unstable masstransfer. WOCS 4540 likely resulted from stable mass transfer during periastronpassage in an eccentric binary system, while WOCS 5379 challenges our currentunderstanding of the expected outcomes for mass transfer from red giant branchstars. Both systems are examples of the value in using detailed analyses tofine-tune our physical understanding of binary evolutionary processes.

Constraining Mass Transfer Histories of Blue Straggler Stars with COS Spectroscopy of White Dwarf Companions