Single-Degenerate Type Ia Supernovae Are Preferentially Overluminous

Recent observational and theoretical progress has favored merging and helium-accreting sub-Chandrasekhar mass white dwarfs in the double-degenerate and the double-detonation channels, respectively, as the most promising progenitors of normal Type Ia supernovae (SNe Ia). Thus the fate of rapidly-accreting Chandrasekhar mass white dwarfs in the single-degenerate channel remains more mysterious then ever. In this paper, we clarify the nature of ignition in Chandrasekhar-mass single-degenerate SNe Ia by analytically deriving the existence of a characteristic length scale which establishes a transition from central ignitions to buoyancy-driven ignitions. Using this criterion, combined with data from three-dimensional simulations of convection and ignition, we demonstrate that the overwhelming majority of ignition events within Chandrasekhar-mass white dwarfs in the single-degenerate channel are buoyancy-driven, and consequently lack a vigorous deflagration phase. We thus infer that single-degenerate SNe Ia are generally expected to lead to overluminous 1991T-like SNe Ia events. We establish that the rates predicted from both the population of supersoft X-ray sources and binary population synthesis models of the single-degenerate channel are broadly consistent with the observed rates of overluminous SNe Ia, and suggest that the population of supersoft X-ray sources are the dominant stellar progenitors of SNe 1991T-like events. We further demonstrate that the single-degenerate channel contribution to the normal and failed 2002cx-like rates is not likely to exceed 1% of the total SNe Ia rate. We conclude with a range of observational tests of overluminous SNe Ia which will either support or strongly constrain the single-degenerate scenario.Comment: 12 pages, 2 figures, accepted to Astrophysical Journal. Comments welcom

Meshed Ministry: Retaining Young Adults During their Complex Migration into Adulthood

Most studies indicate over two-thirds of churched young adults stop participating in church life one year after high school graduation. This generation represents one of the least churched generations in American history. After spending millions of dollars on elaborate children’s and youth programs, churches experience young adult attrition. Young adults themselves seem ill prepared for this life stage. Churches who do not intentionally address the needs of young adults or view the exodus as inevitable miss the mandate to facilitate lifelong followers of Jesus. In Section One, a review of developmental markers, faith stage development theory, and the uniqueness of the current young adult predicament reveals young adults are in a transitional stage of life, typically are between the ages of eighteen to twentynine, and are traversing the complex migration from adolescence to adulthood. These findings are integrated into an analysis of young adult church attrition. Young adult migration is accentuated by critical distancing from previous authority structures and establishing new authority sources. Situational and ideological factors catalyze their departure from church life. In Section Two, I analyzed alternate ways the Christian community has attempted to retain young adults. In Section Three, I offer a solution for young adult attrition called “Meshed Young Adult Ministry.” Meshed ministry builds on four modalities: (1) adaptable engagement; (2) interlaced structures; (3) elastic shaping; and (4) breathable sanctuaries. These modalities represent modes of ministry rather than specific steps to implement. The artifact for this study, a website for church leaders, will include examples of practical ways to implement Meshed ministry as well as expand on the material covered

Land Grant Application- Jumper, Daniel (Harrison)

Land grant application submitted to the Maine Land Office for Daniel Jumper for service in the Revolutionary War.https://digitalmaine.com/revolutionary_war_me_land_office/1514/thumbnail.jp