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Tag: Astronomy and Astrophysics

  • Interacting dark energy and dark matter models fit current data

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    What the study found The study found that two versions of a cosmological model with interacting dark energy and dark matter can fit current observations well. The models use a Gauss–Bonnet-coupled scalar field as dark energy and a fermionic dark matter field, with either an exponential or a power-law scalar potential. Why the authors say…

  • High-mass companions can widen common-envelope outcomes in giant stars

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    What the study found The study found that higher companion mass ratios can produce wider orbits after a common-envelope event, which is an episode where two stars share a single outer envelope. Even so, the widest separation predicted here was still only about 50 solar radii, smaller than the observed range. Why the authors say…

  • Shear before gelation did not change final geopolymer strength

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    What the study found Shearing a sodium silicate-activated metakaolin geopolymer before its critical gel point did not change the critical gel time, the viscoelastic properties after the set point, or the 7-day compressive strength. The study also reports that metakaolin geopolymers kept their compressive strength after six months of testing in low Earth orbit. Why…

  • Collapsar model can match some kilonova-like bursts

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    What the study found The authors report that recent kilonova-like emission after long-duration gamma-ray bursts, including GRB 211211A and GRB 230307A, can be explained by a collapsar scenario rather than only by a merger of two neutron stars. Why the authors say this matters The study suggests that a red evolution in these transients does…

  • Neutron-capture uncertainties limit r-process residuals

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    What the study found Some r-process, or rapid neutron-capture, isotope residuals in the solar system remain significantly uncertain because uncertainties in s-process, or slow neutron-capture, abundances propagate into them. Why the authors say this matters The authors say this is important because r-process residuals are used as a benchmark in stellar models of explosive nucleosynthesis,…

  • Kerr-de Sitter black holes show stronger repetitive energy return

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    What the study found The study found that, compared with a Kerr black hole, a Kerr-de Sitter black hole can produce higher energy return on investment (EROI) and higher single-extraction energy capability in the repetitive Penrose process. The results also depend on the cosmological parameter and the decay radius. Why the authors say this matters…

  • NuSTAR sees a hard X-ray state after MAXI J1752–457 superburst

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    What the study found MAXI J1752–457 was observed with NuSTAR after a superburst, and the source was confirmed to match the previously seen Einstein Probe source EP240809a. The hard X-ray emission was consistent with a spherical blackbody component plus a steep nonthermal power-law component. Why the authors say this matters The authors conclude that the…

  • Nearby black holes fall into three imaging frequency classes

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    What the study found Nearby supermassive black hole accretion flows can be grouped into three classes based on whether they become transparent at traditional imaging frequencies, require higher frequencies, or are unlikely to be transparent down to the black hole shadow in the submillimeter band. Why the authors say this matters The study suggests these…

  • BAGLE adds binary lens and source models for microlensing

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    What the study found The BAGLE Python software package now includes models for binary sources and binary lenses in gravitational microlensing. These models include Keplerian orbits, as well as simpler descriptions of orbital motion such as acceleration, linear, or stationary motion of the secondary companion. Why the authors say this matters The authors say these…

  • Subgrid dynamo model reproduces magnetic field cycles in thin disks

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    What the study found A subgrid model of a helical large-scale dynamo with dynamical quenching was derived and implemented in general-relativistic resistive magnetohydrodynamic simulations of geometrically thin accretion disks. The model reproduced butterfly diagrams seen in earlier simulations and, in some cases, produced weak collimated polar outflows. Why the authors say this matters The authors…