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宇宙工学・惑星科学・宇宙物理の最新プレプリント。

astro-ph.EPastro-ph.SR

Three new exoplanet systems from the Dispersed Matter Planet Project

J. R. Barnes, C. A. Haswell, Z. O. B. Ross, E. Rutherford, M. R. Standing, A. T. Stevenson, D. Staab, L. Fossati et al.

We present a radial velocity analysis of three bright, low-activity stars identified by the Dispersed Matter Planet Project (DMPP). We use a Bayesian framework to compare purely Keplerian models with models incorporating stellar activity via a quasi-periodic Gaussian Process (GP). DMPP-7 (HD 118006) is a slightly evolved star that harbours a single 0.72 Saturn-mass giant ($m_\textrm{p}\sin i$ = 69 M$_\oplus$) with an orbital period of P = 4.93 d. A longer 21 d - 22 d period cannot be conclusivel…

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astro-ph.SR

First and Comprehensive Study of V0757 Pup : $γ-$Doradus Pulsator in Detached Eclipsing Binary

Bakuh Danang Setyo Budi, Bryant Randolph, Rafa Nanda Akilah, Evan Irawan Akbar, Hakim Luthfi Malasan, Puji Irawati

Pulsating stars in detached eclipsing binary (EA) systems are known for providing many important physical informations which constrain both stellar structure and evolution theories. To date, fewer than 50 $γ$ Doradus (GDOR) stars have been found in eclipsing binary systems, making them important targets to study \textit{g}-mode pulsation inside the stars. We present a comprehensive physical and pulsational analysis of V0757 Pup (TIC 6939791), a detached eclipsing binary system observed by the TE…

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astro-ph.EP

Chemical Tracers for 3D Atmospheric Asymmetries on WASP-69 b

Nidhi Bangera, Ludmila Carone, Vikas Soni, Kenneth Goodis Gordon, Luca Fossati, Helena Lecoq-Molinos, Paul B. Rimmer, Peter Woitke et al.

Warm giant exoplanets exhibit strong three-dimensional temperature contrasts that can significantly alter atmospheric chemistry through quenching and photochemistry, yet transmission spectra are commonly interpreted using one-dimensional, limb-averaged models. Such simplifications may bias inferred atmospheric properties, particularly metallicity and C/O ratio. In this work we investigate the relative influence of atmospheric composition and three-dimensional thermal structure on atmospheric che…

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astro-ph.IMastro-ph.HE

SPORE: An Event-Level Sampling Pipeline for Multi-Telescope Neutrino Astronomy

Jeffrey Lazar, Perrine Wilmet, Gwenhaël de Wasseige

We present an open-source Python package for simulating neutrino events from astrophysical point and extended sources using tabulated instrument response functions (IRFs). The package encodes three detector response components - effective area, point spread function, and energy resolution - in a selection-agnostic HDF5 format, which can represent a neutrino telescope whose response is supplied in that form, whether from a public release or a private study. Sampling algorithms cover point sources…

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astro-ph.SR

Results from the first spectropolarimetric survey of $γ$ Dor pulsators

J. Labadie-Bartz, R. Ouazzani, C. Neiner, V. Antoci, P. Stanley, T. Natan, K. Thomson-Paressant, S. D. Chojnowski et al.

Context. Magnetic fields can have an important influence on stellar structure and evolution. In intermediate-mass (A- and F-type) stars, there are many known stars with directly measured strong, globally organized magnetic fields, as well as indications of weak and/or small-scale variable fields. However, among the intermediate-mass $γ$ Dor pulsators, there are no known stars with strong surface magnetic fields. Aims. The broad goal of this work is to search for evidence of strong, globally orga…

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gr-qcastro-ph.IM

Taiji Resolving Power for the Transverse Scalar Mode of Gravitational Waves

Bo-Xuan Ge, Zhoujian Cao

We investigate how small a co-propagating transverse-scalar component can be resolved by Taiji in an already identified bright tensor chirp. Using a source-tracked tensor-null response, we formulate the problem in terms of the minimum resolvable scalar strain fraction and evaluate it over the sky. For a one-year benchmark chirp with tensor signal-to-noise ratio $ρ_T=1000$, we find that Taiji can rule out transverse-scalar strain fractions $ε_b\gtrsim0.532\%$ at the all-sky median level. The thre…

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astro-ph.SR

Statistics of Solar Filament Mass based on CHASE Sun-as-a-star Spectroscopic Observations

T. Y. Xie, Z. H. Zhao, X. Cheng, Y. H. Chen, Z. Zheng, Q. Hao, C. Li, M. D. Ding et al.

Filaments are cool and dense plasmas suspended in the hot corona of the Sun and other stars. Accurately estimating their masses is of great significance for understanding subsequent eruptions and induced space weather effects, but it remains hindered by their intrinsic geometric uncertainties, particularly in spatially unresolved stellar observations. To test and calibrate the methods for estimating the masses of stellar filaments, we conduct a statistical Sun-as-a-star analysis of solar filamen…

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astro-ph.EP

Infrared-to-visible albedo ratio of Phobos: Comparison with primitive asteroids

T. J. Dyer, J. Beccarelli, M. Delbo, C. Avdellidou, M. Pajola, A. Milton, A. Lucchetti, G. Munaretto et al.

Aims. The ratio between infrared and visible albedo, pIR/pV, provides a simple proxy for the spectral slope of asteroid surfaces between the visible and near-infrared wavelength ranges. The aim of this work is to assess whether the different spectral units of Phobos occupy the same spectral parameter space as the primitive asteroid populations in order to confirm or not its possible asteroidal origin. Methods. For each of the three spectral units of Phobos (Red, Transitional and Blue), we extrac…

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astro-ph.HE

Radio flares and X-ray hardening embedded in the long soft state of 4U 1543-475

Zuobin Zhang, Rob Fender, Jiachen Jiang, Payaswini Saikia, David M. Russell, Andrew Hughes, Honghui Liu, Francesco Carotenuto et al.

We present a comprehensive multi-wavelength study of the black hole X-ray binary 4U 1543-475 during its 2021 outburst, focusing on radio flaring episodes that are commonly interpreted as signatures of episodic jet production and are embedded within states when the X-ray emission was dominated by an accretion disk component. The radio monitoring reveals at least two discrete flares that coincide with periods of enhanced Comptonized X-ray emission. Broadband spectral modelling shows a significant…

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astro-ph.HE

Cherenkov light as a mechanism for light flashes seen by astronauts in space

Dominika Švecová, Pavol Bobík, Blahoslav Pastirčák

Astronauts first reported light flashes during the Apollo 11 mission. These events have since been associated with cosmic rays, although their underlying mechanism remains uncertain. This study investigates possible formation processes using Geant4 simulations of cosmic ray interactions in a simplified model of the human eye. We apply published models of human visual perception to the simulated particle induced photons and compare the resulting light flash rates with experimental observations. O…

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astro-ph.GA

Molecule-specific diffusion and desorption of interstellar ices on carbonaceous dust

Yi-Hsuan Chiu, Tushar Suhasaria, Cornelia Jäger, Chun-Yi Lee, Ko-Ju Chuang, Thomas Henning, Yu-Jung Chen

Interstellar ices form on dust grains in the coldest regions of molecular clouds and preserve key volatile reservoirs that could be incorporated into protoplanetary disks during star and planet formation. However, the effect of the dust surface composition on the ice structure and spectroscopic behavior remains poorly constrained. We present a comparative laboratory study of astrophysically relevant ices (CO, CO2, and H2O) deposited on inert calcium fluoride (CaF2) substrate and carbonaceous dus…

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astro-ph.EP

Altered Cosmic Organics as Venus' Ultraviolet Absorbers

Rakesh Mogul, Mikhail Yu. Zolotov, Michael J. Way, Sanjay S. Limaye

Venus' ultraviolet (UV) absorbers significantly contribute to the atmosphere's energy budget. However, the composition of these absorbers remains a mystery. Here, we show that mixtures of polycyclic aromatic hydrocarbons (PAHs) and iron-bearing compounds, analogs of altered cometary dust, excellently match Venus' spectra from the cloud tops to the sub-cloud atmosphere across the UV and visible wavelengths. The molecular compositions for the cloud tops (5-10 ring PAHs and ferric chloride), decomp…

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astro-ph.IMastro-ph.HEgr-qc

LIGO A$^\sharp$: Detector Design and Science Prospects Beyond A+

L. Sun, K. Kuns, B. J. J. Slagmolen, P. Fritschel, P. Schmidt, B. T. Lantz, S. S. Y. Chua, Divyajyoti et al.

We present the LIGO A$^\sharp$ detector concept, an upgrade for the LIGO observatories based on room-temperature interferometers beyond the fifth observing run (O5). Building on the A+ sensitivity, A$^\sharp$ targets broadband sensitivity improvements through heavier test masses, improved suspensions and seismic isolation, increased arm-cavity power, enhanced frequency-dependent squeezing, reduced coating thermal noise considering two scenarios, and improved control of mechanical motion and opti…

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astro-ph.SR

Disco in the Dust: Reflected light at the bow shock around Betelgeuse's companion explains its observed luminosity

Jared A. Goldberg, Meridith Joyce, Anna J. G. O'Grady, Sam D. Barber, Logan J. Prust, Mitchell Dennis, László Molnár, Christian I. Johnson et al.

Recent detections of $α$ Orionis B, the putative companion to Betelgeuse, have been reported using multiple instruments and techniques. These include, most recently, a $>6σ$ detection using VLT/SPHERE reported by Montarges+2026. The authors infer a bright companion ($\sim10^{-3}\times$ Betelgeuse's luminosity) with a mass of $2-3\,M_\odot$ and $T_\text{eff}\approx10-12{,}000$\,K, loosely consistent with the uppermost bounds of Howell+2025's recent mass estimate from speckle-imaging. However, it…

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astro-ph.IM

Towards Genuine Coexistence: Per-Satellite Emission and Radiation Limits to Protect Radio Astronomy and Geodetic VLBI at 1-14 GHz from Satellite Constellations

Balthasar Indermuehle, Lucia McCallum, Emma van der Wateren, Hayo Hase, Benjamin Winkel, Liroy Lourenco, Federico Di Vruno, Michael Lindqvist et al.

Geodetic very long baseline interferometry (VLBI) is a vulnerable application of the radio astronomy service (RAS): it provides the fundamental link between the celestial and terrestrial reference frames, and is the only technique that uniquely determines UT1-UTC. The next-generation geodetic VLBI Global Observing System (VGOS) achieves millimetre accuracy by synthesising group delay across 3-14 GHz using 32x32 MHz channels, most of which lie outside RAS primary allocations. The SNIFFLES-I surve…

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astro-ph.HE

A Radiation-Hydrodynamic Light Curve Grid and Interpolation Framework for Stripped-Envelope Supernovae

Qiliang Fang, Takashi J. Moriya

We present a grid of 8,148 stripped-envelope supernovae (SESNe) light curves based on radiation hydrodynamic simulations of exploding helium-star progenitors. The grid spans an ejecta-mass range representative of typical SESNe, together with broad ranges of explosion energies, radioactive nickel masses, and degrees of material mixing. We systematically investigate how these physical parameters shape the light curves and develop an interpolation-based parameter inference framework that enables th…

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astro-ph.EPastro-ph.IM

Dynamic Trajectory Analysis of Meteoroids Showing Minimal Deceleration

Thomas Stevenson, Ellie Sansom, Hadrien Devillepoix, Maria Gritsevich, Anna Zappatini, Peter Jenniskens, Christopher Herd, Jonti Horner et al.

Meteoroids decelerate and ablate as they descend through the atmosphere, however a portion of instrumentally observed meteors show little measurable deceleration and remain poorly characterised. These are referred to as minimally decelerating objects (MDOs). The traditional alpha-beta method of dynamic trajectory analysis cannot reliably determine their preatmospheric masses or rates of ablation. We present a new approach for estimating the ballistic coefficients (alpha) and mass loss parameters…

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gr-qcastro-ph.HEhep-ph

Constraints on ultralight bosons from merging binary and remnant black holes observed during the second and third parts of the fourth LIGO-Virgo-KAGRA observing run

The LIGO Scientific Collaboration, the Virgo Collaboration, the KAGRA Collaboration, A. G. Abac, A. Abe, I. Abouelfettouh, F. Acernese, K. Ackley et al.

We present constraints on ultralight bosons using binary black hole mergers observed in the second and third parts of the fourth LIGO-Virgo-KAGRA observing run. Directed searches are conducted for long-transient gravitational waves from ultralight vector boson clouds around merger remnants, using a hidden-Markov-model (HMM) tracking scheme. We target the remnant black holes formed in the binary coalescences that produced GW250114 and GW250207. We find no evidence for such signals from either tar…

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astro-ph.GA

Testing Covarying Coupling Constants (CCC) against the full SPARC rotation-curve sample: a like-for-like comparison with MOND and NFW

Rajendra P. Gupta, Nikolaos Samaras

The Covarying Coupling Constants (CCC) framework, developed to account for high-redshift JWST observations, contains a mechanism -- a covarying-constant effective mass field keyed to local density -- that modifies galactic dynamics without particle dark matter. We test it against the full Spitzer Photometry and Accurate Rotation Curves (SPARC) sample of 175 disc galaxies, extending an earlier study of a few objects. Working in an inverse formulation, in which each model predicts the baryonic rot…

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astro-ph.SR

A Helium-shell Burning Blue Horizontal Branch Star Produced from Common Envelope Evolution

Jiao Li, Changqing Luo, Hai-Liang Chen, Zhicun Liu, Bo Zhang, Shi Jia, Hongwei Ge, Tao Wu et al.

Observationally, blue horizontal branch (BHB) stars are defined as hot stars occupying a characteristic region between the extreme blue horizontal branch and RR Lyrae variables in the Hertzsprung-Russell diagram. Most of them are interpreted as stripped core-helium-burning stars, but the role of binary interaction in their formation remains unclear. Here, we report the discovery of a metal-rich BHB star in a 0.82628-day binary system (\Feige 64) comprising a $0.35\pm0.03\,M_{\odot}$ BHB star and…

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astro-ph.SR

A Helium-shell Burning Blue Horizontal Branch Star Produced from Common Envelope Evolution

Jiao Li, Changqing Luo, Hai-Liang Chen, Zhicun Liu, Bo Zhang, Shi Jia, Hongwei Ge, Tao Wu et al.

Observationally, blue horizontal branch (BHB) stars are defined as hot stars occupying a characteristic region between the extreme blue horizontal branch and RR Lyrae variables in the Hertzsprung-Russell diagram. Most of them are interpreted as stripped core-helium-burning stars, but the role of binary interaction in their formation remains unclear. Here, we report the discovery of a metal-rich BHB star in a 0.82628-day binary system (Feige 64) comprising a $0.35\pm0.03\,M_{\odot}$ BHB star and…

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astro-ph.GA

Chemistry here and there: Comparison between the CMZ of the Milky Way and NGC 253

Sergio Martín, Álvaro López-Gallifa, David San Andrés, Victor Rivilla, ALCHEMI Collaboration

For decades, chemical studies in external galaxies have been limited by sensitivity, resolution, bandwidth or a combination of them. A decade of ALMA operations, made the detailed study of the molecular abundances in nearby galaxies a routine job. We can finally bridge the ISM chemistry from Galactic to extragalactic environments, through one to one comparison, albeit probing significantly different scales. The ALMA large program ALCHEMI imaged the chemistry of the starburst galaxy NGC 253 at an…

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astro-ph.SRastro-ph.GA

Numerous bow shocks in the outer Helix Nebula

Pieter van Dokkum, Roberto Abraham, William P. Bowman, Seery Chen, Steven R. Janssens, Deborah M. Lokhorst, Imad Pasha, Carter Rhea et al.

Near the end of their lives, low- and intermediate-mass stars expel metal-enriched material in winds and outflows, ultimately producing planetary nebulae (PNe). The ejected material is expected to fragment and mix into the interstellar medium (ISM), but this final assimilation step has been difficult to observe directly. Here we report evidence for this process in the form of twenty-two bow shocks in the eastern outskirts of the Helix Nebula, detected in H$α$ emission with the partially complete…

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astro-ph.SRastro-ph.EPastro-ph.IM

Diameters and Temperatures VII: High-angular resolution measurements of Solar-type stars with the CHARA Array

Tabetha S. Boyajian, Ashley A. Elliott, Emelly D. Tiburcio, Kaspar von Braun, Gail Schaefer, Timothy R. White, Daniel Huber, Michael Ireland et al.

We present interferometric measurements of angular diameters for 27 nearby solar-type stars obtained with the Precision Astronomical Visible Observations (PAVO) beam combiner at the CHARA Array. The sample spans a broad range of metallicities, includes several known exoplanet hosts, and covers evolutionary stages from the zero-age main sequence to mildly evolved subgiants. Uniform-disk and limb-darkened angular diameters were measured for each target and combined with bolometric fluxes and Gaia…

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astro-ph.SRphysics.space-ph

Solar-Cycle Modulation and Photospheric Magnetic Control of Turbulence in the Young Solar Wind

Yanwen Wang, Rohit Chhiber, Arcadi V. Usmanov, Marc Swisdak, William H. Matthaeus

The solar wind is an outflow of solar plasma that expands from the corona to fill the heliosphere. Its turbulence provides a pathway for non-adiabatic heating and acceleration, and is therefore central to understanding the thermodynamic and magnetohydrodynamic (MHD) evolution of the young solar wind. However, the variation of its turbulence properties over the solar activity cycle and the connection of these properties to solar source regions remains incompletely understood. Here we analyze obse…

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astro-ph.GAastro-ph.CO

Magnetic fields in extreme primordial halos: turbulent collapse and implications for early quasar formation

V. B. Díaz, D. R. G. Schleicher, M. A. Latif, R. Banerjee

It is sometimes suggested that the most massive quasars at high redshift may have formed from rare high-sigma peaks in the cosmic density field. We explore here the evolution in a massive primordial halo corresponding to one of these rare sigma peaks, employing cosmological high-resolution magneto-hydrodynamical zoom-in simulations with initial field strength of $10^{-14}-10^{-8}$ G. The dark matter halo forms at the intersection of strongly convergent flows, leading to the formation of highly s…

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astro-ph.HEgr-qc

Long-duration GW Searches for Sub-solar NSs and Superkilonovae using CoCoA

Abby Tejera, Divyajyoti, Alessandra Corsi, Yossef Zenati, Robert Coyne, Logan Cote

On 2025 August 18, the LIGO-Virgo-KAGRA collaboration reported a sub-threshold gravitational-wave (GW) candidate, S250818k, consistent with a binary neutron star (NS) merger potentially involving a sub-solar-mass compact object. Follow-up electromagnetic (EM) observations identified a Type IIb supernova, SN 2025ulz within the broad localization area of the GW signal. This potential link between a sub-solar GW event candidate and a Type IIb SN, while not confirmed given the low statistical signif…

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astro-ph.GA

From blue to red spirals: Slow galaxy transformation via ram pressure stripping in TNG-50

V. Lora, J. I. Gonzalez-Carbajal, A. Pasquali, A. Marasco, J. Fritz, E. K. Grebel, J. P. Ortiz-Jimenez, S. Estrada-Dorado et al.

Late-type galaxies lose gas through ram-pressure stripping (RPS) after falling into a massive halo. Because this mechanism primarily removes the gaseous component while leaving the stellar disk largely undisturbed, it provides a pathway for quenching star formation without immediate morphological transformation. While RPS is well established in galaxy clusters, galaxy evolution in low-mass groups is often attributed to mergers, leaving open the question of whether RPS alone can drive the transit…

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astro-ph.EP

Spectral Energy Distribution Analysis for Habitable Worlds Observatory Target Stars

Stephen R. Kane, Kaspar von Braun, Tara Fetherolf, Natalie R. Hinkel

The Habitable Worlds Observatory (HWO) will directly image and characterize planets potentially similar to Earth orbiting nearby stars. Accurate stellar properties, particularly effective temperatures ($T_\mathrm{eff}$), angular diameters ($θ_\star$), and bolometric fluxes ($F_\mathrm{bol}$), are essential for reliable Habitable Zone (HZ) calculations, exoplanet yield predictions, and coronagraph design trade studies. We present a spectral energy distribution (SED) analysis for the 164 stars fro…

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astro-ph.EP

A Pair of Warm Saturn-mass Planets near the 2:1 Mean Motion Resonance around TOI-3850

Sean Collins, Michelle Kunimoto, Nicolas B. Cowan, Keivan G. Stassun, Jack J. Lissauer, Ze'ev Vladimir, Teo Močnik, Ernesto Elenter et al.

Warm Jupiters, with orbital periods of $10$--$200~\rm{days}$ and radii exceeding $8~R_{\oplus}$, are a relatively understudied class of exoplanets occupying the parameter space between hot Jupiters and more widely separated, colder Jupiter analogs. In this work, we report the detection of a multi-planet warm Jupiter system around TOI-3850 (TIC-143008050), a moderately active, near-solar metallicity G0 dwarf star observed by TESS in Sectors 15, 21, 41, 48 and 75. Initially, a single candidate pla…

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