Tootfinder

Neue Rekordzahlen: "Star Wars Battlefront 2" erlebt Renaissance
Plötzlich redet das ganze Internet darüber: Obwohl "Star Wars Battlefront 2" seit Jahren keine Updates mehr bekommen hat, gibt es einen neuen Spielerrekord.

Study of the peculiar variable star Khavchenko 1
A. E. Maslak, D. V. Denisenko
https://arxiv.org/abs/2507.00149 https://arxiv.org/pdf…

Study of the peculiar variable star Khavchenko 1
The work is devoted to the study of the peculiar variable star Khavchenko 1 in Auriga. It was discovered by the 7th grade student Sergey Khavchenko in 2020. The brightness of the star varies with an amplitude of about 0.4 magnitude and the period of 4.213 days. Initially the star could not have been attributed to any known type of variability. Its light curve looks like the upside-down light curve of the eclipsing binary similar to that of luminous red nova V1309 Scorpii a few years before the …

VR- und KI-Brillen sind nur Brücken: Der heimliche Star heißt Augmented Reality
Während VR lange Zeit lautstark um Aufmerksamkeit buhlte, schleicht sich AR in unser Leben, um zu bleiben – auf dem Rücken von Mixed Reality und Smart Glasses.

This https://arxiv.org/abs/2410.17312 has been replaced.
initial toot: https://mastoxiv.page/@arXiv_…

Chemical Abundances in the Leiptr Stellar Stream: A Disrupted Ultra-faint Dwarf Galaxy?
Chemical abundances of stellar streams can be used to determine the nature of a stream's progenitor. Here we study the progenitor of the recently discovered Leiptr stellar stream, which was previously suggested to be a tidally disrupted halo globular cluster. We obtain high-resolution spectra of five red giant branch stars selected from the Gaia DR2 STREAMFINDER catalog with Magellan/MIKE. One star is a clear non-member. The remaining four stars display chemical abundances consistent with those…

Cameo von Netflix-Chef bei TV -Serie: Apple wollte lieber Tim Cook
Anekdote vom Set der erfolgreichen TV -Dramedy-Serie "The Studio": Star Seth Rogen ließ den Netflix-Chef auftreten, doch das schmeckte Apple nicht.

Critical Metallicity of Cool Supergiant Formation. II. Physical Origin
Po-Sheng Ou, Ke-Jung Chen
https://arxiv.org/abs/2506.01753 https://

Critical Metallicity of Cool Supergiant Formation. II. Physical Origin
This study investigates the physical origin of the critical metallicity ($Z_{\rm c}\sim 0.001$) required for the formation of cool supergiants, as revealed by stellar evolution models. Using model grids that vary in mass, metallicity, opacity, and nuclear reaction rates, we identify a threshold terminal-age main-sequence (TAMS) radius ($R_{\rm T}$) that determines whether a star of a given mass can evolve into the red supergiant (RSG) phase. Through stellar models and homology relations, we sho…

Transient star B/R ratio and star formation in $z\gtrsim 1$ lensed galaxies
Sung Kei Li, Jose M. Palencia, Jose M. Diego, Jeremy Lim, Patrick L. Kelly, Ashish K. Meena, James Nianias, Hayley Williams, Liliya L. R. Williams, Adi Zitrin
https://arxiv.org/abs/2506.17565

Transient star B/R ratio and star formation in $z\gtrsim 1$ lensed galaxies
The extreme magnification from galaxy clusters and microlenses therein allows the detection of individual, luminous stars in lensed galaxies as transient events, and hence provides a valuable window into the high mass stellar population in $z>1$ galaxies. As these bright stars can only be formed at specific ages, the relative abundance of transient events at blue (B) and red (R) optical wavelengths ($B/R$ ratio) can provide insights into the star formation history of lensed galaxies. Here, we f…

First images of the Sun's south pole!
Solar Orbiter is the first space probe to look at the Sun's poles – and finds the magnetic field there in a state of turmoil. The Sun's magnetic field is currently undergoing a flip. During its latest flyby of the Sun at the end of March this year, the Solar Orbiter space probe had its first clear view of our star's poles. First images:

We hoofed it up Mill Mountain before the heat ~really~ set in. The humidity did not wait, unfortunately, but we enjoyed it all the same.
We are now decamped in a coffee shop and pondering lunch options. I think we’re off to a bistro and bakery we’ve heard great things about. Their Better Than Sex cake is reputed to be true to its name.

On Saturday I met Freddie greyhound, Mandy greyhound's nephew¹. Mandy passed away in 2021.
Coincidentally both homed by WGW and Freddie now lives a few miles from where Mandy lived her pet life. His human knows Mandy's humans well.
Considering the rather small greyhound gene pool this is not unusual. Mandy's sire has had over 5,000 offspring so far.
#Greyhounds

About 90 minutes after sunset, look for red Mars shining next to the similarly bright Regulus, one of our brightest stars. Regulus, a member of the Leo constellation, is actually a quadruple star system composed of four stars organized into two pairs.
#stars #Heavens

Mass-feeding of jet-launching white dwarfs in grazing and common envelope evolution
Noam Soker (Technion, Israel)
https://arxiv.org/abs/2505.22621 https://…

Mass-feeding of jet-launching white dwarfs in grazing and common envelope evolution
I propose a scenario that allows white dwarfs (WDs) to launch relatively powerful jets when they enter a common envelope evolution (CEE) or experience a grazing envelope evolution (GEE) with a red giant branch star (RGB) or an asymptotic giant branch (AGB) star. In this, still a speculative scenario, the accretion for a time is mainly onto an accretion disk with a radius of ~ 1Ro that increases in mass. The accretion disk launches the powerful two opposite jets by releasing gravitational energy…

Low-metallicity nova explosions: a site for weak rp-process nucleosynthesis
Athanasios Psaltis, Jordi Jos\'e, Richard Longland, Christian Iliadis
https://arxiv.org/abs/2506.15162

Low-metallicity nova explosions: a site for weak rp-process nucleosynthesis
Classical novae are common cataclysmic events involving a binary system of a white dwarf and a main sequence or red giant companion star. In metal-poor environments, these explosions produce ejecta different from their solar counterparts due to the accretion of sub-solar metallicity material onto the white dwarf. In particular, it has been suggested that the nucleosynthesis flow in such low-metallicity nova explosions extends up to the Cu-Zn region, much beyond the expected endpoint, around Ca,…

10,000 Resolved Triples from Gaia: Empirical Constraints on Triple Star Populations
Cheyanne Shariat, Kareem El-Badry, Smadar Naoz
https://arxiv.org/abs/2506.16513

10,000 Resolved Triples from Gaia: Empirical Constraints on Triple Star Populations
We present a catalog of $\sim 10,000$ resolved triple star systems within 500 pc of the Sun, constructed using Gaia data. The triples include main-sequence, red giant, and white dwarf components spanning separations of 10 to 50,000 au. A well-characterized selection function allows us to constrain intrinsic demographics of the triple star population. We find that (a) all systems are compatible with being hierarchical and dynamically stable; (b) mutual orbital inclinations are isotropic for wide…

On Saturday I met Freddie greyhound, Mandy greyhound's nephew¹. Mandy passed away in 2021.
Coincidentally both homed by WGW and Freddie now lives a few miles from where Mandy lived her pet life. His human knows Mandy's humans well.
Considering the rather small greyhound gene pool this is not unusual. Mandy's sire has had over 5,000 offspring so far.
#Greyhounds

#ndwgoecountdown Weltraum zum Staunen und Mitmachen
Unterhaltsame Shows für Kinder zum Zuschauen und Mitmachen bieten die Promovierenden des MPI für Sonnensystemforschung. Darin erforschen die Zuschauer*innen das Sonnensystem, erkunden die Oberfläche des Mars, wagen einen „Weltraumspaziergang“ und helfen dabei, unsere nächste Weltraummission zu planen.
Kommt gerne 18:00 …

Axion-like particle constraints from preSN in future experiments
Federica Giacchino
https://arxiv.org/abs/2506.08610 https://arxiv.or…

Axion-like particle constraints from preSN in future experiments
We extend the study of the search for ALP-photon emissions from a Supernovae (SNe) progenitor, the Red Supergiant Star (RGS), as Betelgeuse, arising through a combination of Bremsstrahlung, Compton, and Primako? processes, in the hard-X and MeV energy range, using the next proposed and future experiments, such as COMCUBE, GECCO, COSI, AMEGO-X, and e-ASTROGAM.

A Bimodal Metallicity Distribution Function in the Ultra-Faint Dwarf Galaxy Reticulum II
Alice M. Luna, Alexander P. Ji, Anirudh Chiti, Joshua D. Simon, Daniel D. Kelson, Minsung Go, Guilherme Limberg, Ting S. Li, Anna Frebel
https://arxiv.org/abs/2506.16462

A Bimodal Metallicity Distribution Function in the Ultra-Faint Dwarf Galaxy Reticulum II
Star formation in ultra-faint dwarf galaxies (UFDs, $M_* <10^5M_\odot$) is suppressed by reionization, but may not be completely quenched. The metallicity distribution function (MDF) of stars in ultra-faint dwarf galaxies could show these signatures of reionization. However, past studies of UFD MDFs have been limited, because there are only a few dozen red giant branch (RGB) stars in such low-mass galaxies. We present low-resolution Magellan/IMACS spectroscopy of 167 stars in the UFD Reticulum …

Bulk Viscosity of Two-Flavor Color Superconducting Quark Matter in Neutron Star Mergers
Mark Alford, Arus Harutyunyan, Armen Sedrakian, Stefanos Tsiopelas
https://arxiv.org/abs/2506.08144

Bulk Viscosity of Two-Flavor Color Superconducting Quark Matter in Neutron Star Mergers
This work investigates the bulk viscosity of warm, dense, neutrino-transparent, color-superconducting quark matter, where damping of density oscillations in the kHz frequency range arises from weak-interaction-driven direct Urca processes involving quarks. We study the two-flavor red-green paired color-superconducting (2SC) phase, while allowing for the presence of unpaired strange quarks and blue color light quarks of all flavors. Our calculations are based on the SU(3) Nambu-Jon…

Fine-Tuned Supernova or Failed Explosion? Decoding the Origins of the G3425 Binary
Zsolt Regaly, Viktoria Frohlich, Jozsef Vinko
https://arxiv.org/abs/2506.20386

Fine-Tuned Supernova or Failed Explosion? Decoding the Origins of the G3425 Binary
A binary system (G3425) consisting of a massive unseen component and a red giant star on a nearly circular orbit was recently discovered. The formation of such a system is puzzling because orbital stability generally breaks down due to the large mass loss from the system caused by the SN explosion while forming the unseen component. Analytical solutions of the variable-mass two-body problem suggest that the explosion should have occurred when the component was close to its apocenter to explain …

A Plasma Torus Around a Young Low-Mass Star
Luke G. Bouma, Moira M. Jardine
https://arxiv.org/abs/2506.09116 https://arxiv.org/pdf/25…

A Plasma Torus Around a Young Low-Mass Star
A small fraction of red dwarfs younger than 100 million years show structured, periodic optical light curves suggestive of transiting opaque material that corotates with the star. However, the composition, origin, and even the existence of this material are uncertain. The main alternative hypothesis is that these complex periodic variables (CPVs) are explained by complex distributions of bright or dark regions on the stellar surfaces. Here, we present time-series spectroscopy and photometry of …

New Symbiotic Stars from LAMOST DR10 Spectra and Multi-band Photometry
Jing Chen, Liang Wang, Yin-Bi Li, Xiao-Xiao Ma, A-Li Luo, Zi-Chong Zhang, Ming-Yi Ding, Kai Zhang
https://arxiv.org/abs/2506.09352

New Symbiotic Stars from LAMOST DR10 Spectra and Multi-band Photometry
Symbiotic star (SySt) is long-period interacting binary system, typically consisting of a white dwarf and a red giant surrounded by a nebula. These systems are natural astrophysical laboratories for investigating binary star evolution. In this paper, we identified nine SySts from the LAMOST DR10 low-resolution spectra survey, seven of which were previously known, while two are newly identified. Initially, we selected LAMOST spectra exhibiting typical SySt emission lines (e.g., $\rm H_α, ~H_β,…

Fifty Years of CAK
Jorick S. Vink (Armagh Observatory,Planetarium)
https://arxiv.org/abs/2506.06421 https://arxiv.org/pdf/2506.06421

Fifty Years of CAK
We present a new framework for massive star evolution that is no longer driven by Dutch or other mass-loss rate Recipes, but which take the physics of Gamma or L/M dependent mass loss consistently into account. We first discuss the hot-star mass-loss kink and the transition mass loss rate between optically thin and thick winds, before discussing vertical stellar evolution, mass evaporation, and the maximum black hole (BH) mass. We end with a suggestion that a recently uncovered red supergiant (…

Constraining the physical structure of the circumstellar environment of V838 Monocerotis remnant
Muhammad Zain Mobeen, Tomasz Kami\'nski, Stephen Potter
https://arxiv.org/abs/2506.02812

Constraining the physical structure of the circumstellar environment of V838 Monocerotis remnant
V838 Monocerotis (V838 Mon) erupted in 2002 as a luminous red nova after which it cooled and began to form dust. The remnant is predicted to become a blue straggler. Interferometric observations in the HKLM bands have uncovered a stable bipolar feature in the closest vicinity of the remnant star. We aim to constrain the physical structure and nature of the circumstellar material immediately surrounding V838 Mon. Using the radiative-transfer code RADMC3D we managed to constrain the dust density …