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Will Europa Become a Habitable World When the Sun Becomes a Red Giant? People always want to know what will happen to Earth when the Sun eventually swells up as a red giant. For one thing, the expanding Sun will turn the inner planets into cinders. It will almost certainly spell the end of life on our planet. Mars might become more temperate and hospitable to life. In addition, it could well be a boon for the gas giant Jupiter and its moons. That’s because the habitable zone of the Solar System will move outward from where it is now, to a spot encompassing theRead More →

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In: arXiv

The Paris Meudon ground based support to the NASA Solar Maximum Mission in the eighties Jean-Marie Malherbe (LIRA, PSL) arXiv:2505.20363v1 Announce Type: new Abstract: The Solar Maximum Mission of NASA was one of the first satellites with on board digitization of observations. It was launched for the solar maximum of cycle 21 (1980) in order to study the solar activity. It carried many instruments, such as coronagraphs, X and $gamma$ ray detectors, an Ultra Violet spectrometer and a radiometer. Ground based support was offered by many institutes, such as Paris Meudon observatory under the form of systematic observations or coordinated campaigns with specific instruments. WeRead More →

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Gravitational waves of quasi-circular, inspiraling black hole binaries in an ultralight vector dark-matter environment Tom’as Ferreira Chase, Diana L’opez Nacir, Nicol’as Yunes arXiv:2505.21383v1 Announce Type: new Abstract: The gravitational waves emitted by massive black hole binaries can be affected by a variety of environmental effects, which, if detected, could inform astrophysics and cosmology. We here study how gravitational waves emitted by black holes in quasi-circular orbits are affected by the presence of an ultra-light, vector-field, dark-matter environment that is minimally coupled to the binary. This dark-matter environment induces oscillatory gravitational potentials that perturb the orbit of the binary, leaving an imprint in the binary’s bindingRead More →

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A New Nuclear Rocket Technology Takes Another Step Forward Nuclear Thermal Propulsion (NTP) has stood as a promising potential alternative propulsion technology for decades. Chemical rockets have begun to reach their theoretical maximum efficiency, and their developers have switched their focus to making them cheaper rather than more efficient. NTP should answer that by offering high thrust and specific impulse. NASA’s DRACO Program, the standard-bearer for NTP systems, provides a specific impulse of around 900 seconds, about double a traditional chemical rocket, but half that of most ion thrusters. To increase that number even further, researchers at the University of Alabama at Huntsville and TheRead More →

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New Adaptive Optics Show “Raindrops” on the Sun Modern ground-based telescopes rely on adaptive optics (AO) to deliver clear images. By correcting for atmospheric distortion, they give us exceptional pictures of planets, stars, and other celestial objects. Now, a team at the National Solar Observatory is using AO to examine the Sun’s corona in unprecedented detail. Universe Today Go to SourceRead More →

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Webb telescope helps refines Hubble constant, suggesting resolution to long-standing expansion rate debate For the past decade, scientists have been trying to get to the bottom of what seemed like a major inconsistency in the universe. The universe expands over time, but how fast it’s expanding has seemed to differ depending on whether you looked early in the universe’s history or the present day. If true, this would have presented a major problem to the gold-standard model that represents our best understanding of the universe. phys.org Go to SourceRead More →

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New study suggests how wide-orbit planets form, supporting existence of Planet Nine In the cold, dark outskirts of planetary systems far beyond the reach of the known planets, mysterious gas giants and planetary masses silently orbit their stars—sometimes thousands of astronomical units (AU) away. For years, scientists have puzzled over how these “wide-orbit” planets, including the elusive Planet Nine theorized in our own solar system, could have formed. Now, a team of astronomers may have finally found the answer. phys.org Go to SourceRead More →

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3D velocity analysis of wide binaries supports modified gravity at low acceleration Wide binary stars with separation greater than about 2000 astronomical units are interesting natural laboratories that allow a direct probe of gravity at low acceleration weaker than about 1 nanometer per second squared. Astrophysicist Kyu-Hyun Chae at Sejong University (Seoul, South Korea) has developed a new method of measuring gravity with all three components of the velocities (3D velocities) of stars, as a major improvement over existing statistical methods relying on sky-projected 2D velocities. phys.org Go to SourceRead More →

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One Star Once Orbited Inside the Other in this Bizarre Binary System. Astronomers have spotted a pulsar in a binary system, taking about 3.6 hours for the stars to orbit one another. Their orbit is so close that, from our vantage point, the pulsar’s radio signals vanish for roughly one-sixth of each cycle—blocked by the companion’s interference. Researchers think that the more massive star died first, exploding as a supernova and collapsing into a neutron star, passing within the atmosphere of the other. It took about 1,000 years to blow away the envelope of material. Universe Today Go to SourceRead More →

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Study reinvestigates the properties of globular cluster NGC 1754 Using the Hubble Space Telescope (HST), astronomers have observed a globular cluster known as NGC 1754 as part of a systematic study of the most massive and compact clusters in the Large Magellanic Cloud (LMC). Results of the observational campaign, published May 15 on the arXiv pre-print server, shed more light on the properties of this cluster. phys.org Go to SourceRead More →

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‘Raindrops in the sun’s corona’: New adaptive optics shows stunning details of our star’s atmosphere The sun’s corona—the outermost layer of its atmosphere, visible only during a total solar eclipse—has long intrigued scientists due to its extreme temperatures, violent eruptions, and large prominences. However, turbulence in Earth’s atmosphere has caused image blur and hindered observations of the corona. A recent development by scientists from the U.S. National Science Foundation (NSF) National Solar Observatory (NSO), and New Jersey Institute of Technology (NJIT), is changing that by using adaptive optics to remove the blur. phys.org Go to SourceRead More →

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Astronomers Identified the Lost Star of 1408…Or Have They? Over the past 90 years, astronomers have successfully matched several Chinese historical records of “guest stars” with known supernovae. However, identifying historical novae (smaller stellar explosions) has proven to be far more challenging, with many proposed candidates later turning out to be comets or meteors instead. One particularly debated case involves a guest star recorded in 1408 CE by Chinese astronomers. A team of astronomers now think they may have finally been able to identify the event, a rare nova that could potentially solve this centuries old astronomical mystery. Universe Today Go to SourceRead More →

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Perseverance Photobombed by a Passing Dust Devil On May 10th, while striking a selfie to mark its 1,500th day on Mars, NASA’s Perseverance Rover got an unexpected guest star—a towering dust devil swirling in the distance photobombed the shot. The rover was on Witch Hazel Hill, an area on the rim of Jezero Crater that it has been exploring for the last 5 months. The dust devil on the other hand was sneaking into the background from a distance of 5 km away. The selfie image was made up of 59 separate photos taken by the rover using its WATSON camera. Universe Today Go toRead More →

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The multi-dimensional halo assembly bias can be preserved when enhancing halo properties with HALOSCOPE Sujatha Ramakrishnan, Violeta Gonzalez-Perez, Gabriele Parimbelli, Gustavo Yepes arXiv:2410.07361v2 Announce Type: replace Abstract: Over $90$% of dark matter haloes in cosmological simulations have unresolved properties. This can hinder the dynamical range of simulations and result in systematic biases when modelling cosmological tracers. We aim to more precisely determine unresolved structural and dynamical halo properties while preserving the correlations with environment and halo assembly bias found in simulations. We have developed HALOSCOPE, a machine learning technique that uses multi-variate conditional probability distribution functions. This method ensures that correlations among various halo properties,Read More →

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Comparison of Three Methods for Triggering Core-collapse Supernova Explosions in Spherical Symmetry Liliya Imasheva (MPI Astrophysics, Garching, LMU Munich), H. -Thomas Janka (MPI Astrophysics, Garching), Achim Weiss (MPI Astrophysics, Garching, LMU Munich) arXiv:2501.13172v2 Announce Type: replace Abstract: Despite the three-dimensional nature of core-collapse supernovae (CCSNe), simulations in spherical symmetry (1D) play an important role to study large model sets for the progenitor-remnant connection, explosion properties, remnant masses, and CCSN nucleosynthesis. To trigger explosions in 1D, various numerical recipes have been applied, mostly with gross simplifications of the complex microphysics governing stellar core collapse, the formation of the compact remnant, and the mechanism of the explosion.Read More →

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Constraints on maximum neutron star mass from proto-neutron star evolution Deepak Kumar, Tuhin Malik, Hiranmaya Mishra, Constanc{c}a Provid^encia arXiv:2505.18888v1 Announce Type: cross Abstract: A proto-neutron star (PNS) gets formed after a successful supernova when the stellar remnant decouples from the ejecta. In this study, we explore a relativistic framework for the finite-temperature $beta$-equilibrium limit of equation of state (EOS), constrained via a Bayesian inference methodology. The EOS is constrained by minimal approximations on a few nuclear saturation properties, low-density pure neutron matter constraints from chiral effective field theory, and a neutron star (NS) maximum mass greater than 2.0 $M_{odot}$. Two sets of EOS derived fromRead More →

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Clustering and physical properties of AGN and Star-Forming Galaxies at fixed stellar mass: does assembly bias have a role in AGN activity? Amrita Banerjee, Biswajit Pandey, Anindita Nandi arXiv:2310.12943v2 Announce Type: replace Abstract: We analyze a volume-limited sample from the Sloan Digital Sky Survey (SDSS) to compare the spatial clustering and physical properties of active galactic nuclei (AGN) and star-forming galaxies (SFG) at fixed stellar mass. We find no statistically significant difference in clustering strength or local density between AGN and SFG. However, after matching their stellar mass distributions, we detect statistically significant differences (at a confidence level $>99.99%$) in colour, star formation rate (SFR),Read More →

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First Axion-Like Particle Results from a Broadband Search for Wave-Like Dark Matter in the 44 to 52 $mu$eV Range with a Coaxial Dish Antenna Gabe Hoshino, Stefan Knirck, Mohamed H. Awida, Gustavo I. Cancelo, Simon Corrodi, Martin Di Federico, Benjamin Knepper, Alex Lapuente, Mira Littmann, David W. Miller, Donald V. Mitchell, Derrick Rodriguez, Mark K. Ruschman, Chiara P. Salemi, Matthew A. Sawtell, Leandro Stefanazzi, Andrew Sonnenschein, Gary W. Teafoe, Peter Winter arXiv:2501.17119v2 Announce Type: replace-cross Abstract: We present the results from the first axion-like particle search conducted using a dish antenna. The experiment was conducted at room temperature and sensitive to axion-like particles in theRead More →