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There is now solid experimental evidence of at least one supernova explosion within 100 pc of Earth within the last few million years, from measurements of the short-lived isotope 60Fe in widespread deep-ocean samples, as well as in the lunar regolith and cosmic rays. This is the first established example of a specific dated astrophysical event outside the Solar System having a measurable impact on the Earth, offering new probes of stellar evolution, nuclear astrophysics, the astrophysics of the solar neighborhood, cosmic-ray sources and acceleration, multi-messenger astronomy, and astrobiology. Interdisciplinary connections reach broadly to include heliophysics, geology, and evolutionary biology. Objectives for the future include pinning down the nature and location of the established near-Earth supernova explosions, seeking evidence for others, and searching for other short-lived isotopes such as 26Al and 244Pu. The unique information provided by geological and lunar detections of radioactive 60Fe to assess nearby supernova explosions make now a compelling time for the astronomy community to advocate for supporting multi-disciplinary, cross-cutting research programs., Comment: 11 pages, 2 figures. Astro2020 Science White Paper submitted to the 2020 Decadal Survey on Astronomy and Astrophysics

We explore the initial conditions that lead to detached binary evolution of massive pre-MS binaries and ask how large a fraction of the observed binary systems may have been initially formed as low-mass protobinaries and later undergone a significant accretion phase while remaining detached. We develop a family of analytic models to describe the orbital separation, $a$, and mass ratio, $q$, evolution. For a given mass accretion rate onto the binary system, we define a recipe for distributing this mass between the two components. For this we introduce a parameter $\eta$, such that $\frac{\dot{M}_2}{\dot{M}_1}=q^\eta$ at any time, to determine the binary mass ratio evolution. Depending on the choice of $\eta$, any type of mass ratio evolution is possible. Furthermore, we use MESA, a detailed stellar structure code, to calculate an extensive grid of binary sequences where a protobinary undergoes accretion, and we identify the initial conditions that separates detached from non-detached pre-MS binary evolution. A value of $\eta$ around 2 allows accretion growth in detached systems to form close massive binaries on the Zero Age Main-Sequence with minimum orbital periods down to about 1.2 days for $M_{\rm 1, ZAMS}=20-30M_{\odot}$ twin-binaries. $\eta=2$ can also reproduce the observed population of binary systems with primary stars above $6M_{\odot}$. The whole observed range of massive close binaries can form via accretion growth in detached systems, making the binary formation channel of accretion growth a strong contender to explain the formation of massive close binaries, including progenitors of coalescing binary black holes., Comment: 27 pages, 19 figures, 3 tables, submitted to A&A. Abstract context removed to to fit arXiv

Here we combine observations of open clusters (OCs) with single- and binary population synthesis models and a Galactic potential to reconstruct the SN activity of these OCs during the past 35 Myr. We find that several OCs potentially hosting SN progenitors have passed within 100 pc of the Sun during the past 35 Myr. In particular we find that ASCC 19, NGC 1981, and NGC 1976 are likely to have hosted one or more SNe while passing within 200 pc of the solar system in the period 17 - 12 Myr BP which might have affected Earths' geology and climate. Besides the stellar history of the individual OCs we also compute 1) a spatial and temporal 2D-probability density map showing the most likely position and time of SN from our sample of OCs within 1 kpc during the past 35 Myr, 2) the time series of the SN rate per volume and 3) the relative SN rate compared with today and corrected for OC evaporation of older generations. The SN rate today from core collapse is estimated to be 37.8$\pm$6.1$\rm kpc^{-3} Myr^{-1}$. During the past 35 Myr we find a peak SN rate around 10 Myr before present (BP) where the rate was 40% higher relative to the past 1 Myr. Finally we discuss possible effects of binary stellar evolution in relation to the history of SN production in the solar neighbourhood and the detected $\rm ^{60}Fe$ signal in terrestrial geological samples induced between $\sim$2.2 - 2.8Myr BP., Comment: Submitted to MNRAS. 14 pages, 3 tables, 8 figures

We have endeavoured to understand the formation and evolution of the black hole (BH) X-ray binary LMC X-3. We estimate the properties of the system at 4 evolutionary stages: 1) at the Zero Age Main Sequence (ZAMS), 2) just prior to the supernova (SN) explosion of the primary, 3) just after the SN, and 4) at the moment of RLO onset.We use a hybrid approach, combining detailed stellar structure and binary evolution calculations with approximate population synthesis models. This allows us to estimate potential natal kicks and the evolution of the BH spin. In the whole analysis we incorporate as model constraints the most up-to-date observational information, encompassing the binary's orbital properties, the companion star mass, effective temperature, surface gravity and radius, as well as the black hole's mass and spin. We find that LMC X-3 began as a ZAMS system with the mass of the primary star in the range $M_{\rm{1,ZAMS}}$ = 22-31 $\rm{M_{\odot}}$ and a secondary star of $M_{\rm{2,ZAMS}} = 5.0-8.3M_{\odot}$, in a wide ($P_{ZAMS} \gtrsim 2.000\, \rm days$) and eccentric ($e_{\rm{ZAMS}} \gtrsim 0.23$) orbit. Just prior to the SN, the primary has a mass of $M_{\mathrm{1,preSN}} = 11.1-18.0\,\rm M_{\odot}$, with the secondary star largely unaffected. The orbital period decreases to $0.6-1.7\, \rm days$, and is still eccentric $0 \leq e_{\rm{preSN}} \leq 0.44$. We find that a symmetric SN explosion with no or small natal kicks (a few tens of $\rm km\, s^{-1}$) imparted on the BH cannot be formally excluded, however, large natal kicks in excess of $\gtrsim 120 \,\rm km\, s^{-1}$ increase the estimated formation rate by an order of magnitude. Following the SN, the system has a BH $M_{\mathrm{BH,postSN}} = 6.4-8.2\,\rm M_{\odot}$ and is put into an eccentric orbit. At the RLO onset the orbit is circularised and it has an orbital period of $P_{\rm{RLO}} = 0.8-1.4\,\rm days$., Comment: 23 pages, 10 figures, 6 tables. Submitted to Astronomy and Astrophysics

In this work we present a modeling tool designed to estimate the hysteretic losses in the coils of an electric generator with coils made of coated conductor tapes during transient operation. The model is based on a two-stage segregated model approach that allows simulating the electric generator and the current distribution in the superconducting coils using a one-way coupling from the generator to the HTS coils model. The model has two inputs: the rotational speed and the electric load signal. A homogeneous anisotropic bulk model for the coils allows computing the current distribution in the coils. From this distribution, the hysteretic losses are estimated. Beyond the interest on providing an estimate on the global energy dissipation in the machine, in this work we present a more detailed local analysis that allows addressing issues such as coil design, critical current ratting, electric load change rate limits, cryocooler design, identification of quench-prone regions and overall transient performance.