adsabs/SciX_UAT_keywords huggingface dataset:
Possible Explosive Dispersal Outflow in IRAS 16076-5134 Revealed with ALMA

We present 0.9 mm continuum and CO(3-2) line emission observations retrieved from the Atacama Large Millimeter/submillimeter Array archive toward the high-mass star formation region IRAS 16076-5134. We identify 14 dense cores with masses between 0.3 and 22 M ⊙. We find an ensemble of filament-like CO(3-2) ejections from -62 to +83 km s-1 that appear to arise radially from a common central position, close to the dense core MM8. The ensemble of filaments has a quasi-isotropic distribution in the plane of the sky. The radial velocities of several filaments follow a linear velocity gradient, increasing from a common origin. Considering the whole ensemble of filaments, we estimate the total mass to be 138 and 216 M ⊙, from its CO emission, for 70 K and 140 K, respectively. Also, assuming a constant velocity expansion for the filaments (of 83 km s-1), we estimate the dynamical age of the outflowing material (3500 yr), its momentum (~104 M ⊙ km s-1), and its kinetic energy (~1048-49 erg). The morphology and kinematics presented by the filaments suggest the presence of a dispersal outflow with explosive characteristics in IRAS 16076-5134. In addition, we make a raw estimate of the lower limit of the frequency rate of the explosive dispersal outflows in the galaxy (one every 110 yr), considering a constant star formation rate and efficiency, with respect to the galactocentric radius of the galaxy. This may imply a comparable rate between dispersal outflows and supernovae (approximately one every 50 yr), which may be important for the energy budget of the and the link between dispersal outflows and high-mass star formation.

Keywords: interferometers; star formation; submillimeter astronomy; interstellar dynamics
The First Photometric and Spectroscopic Studies of ASASSN-V J015428.67+204247.2 and its Relation to the Population of Low Mass Ratio Contact Binaries

We performed photometric, spectroscopic and orbital period investigations of ASASSN-V J015428.67+204247.2 (hereafter, J015428) for the first time. The light curves of VRI bands were obtained. Through the analysis of Wilson-Devinney program, J015428 was found as an A-subtype medium contact binary system with a low-mass ratio (q = 0.129, f = 26.8%). The atmospheric parameters were determined in spectroscopic analysis. In the orbital period investigations, we found that the orbital period of J015428 decreases at the rate of -7.13 × 10-8 day yr-1. And the long-term orbital period decrease is possibly due to angular momentum loss (AML). The absolute parameters was calculated with the photometric solutions and Gaia distance. Through the analyses of mass-radius and mass-luminosity diagrams of 54 contact binaries with the low mass ratios (0.096 ≤ q ≤ 0.15), the evolutionary states of low mass ratio binaries were investigated. The results by analyzing the energy transfer parameter indicated that energy transfer rate was a function of mass and bolometric luminosity ratio. We estimated the initial masses and the densities of two components and the age of the binary. The analysis of the orbital angular momentum supposed that J015428 may evolved from a short-period detached binary by AML. J015428 is in a stable contact stage at present.

Keywords: eclipsing binary stars; close binary stars; binary stars; contact binary stars; magnetic stars
Activity in Centaur-like Jupiter-family Comet 2023 RN3

We present multi-filter observations of Centaur-like Jupiter-family comet 2023 RN3 conducted as part of the Las Cumbres Observatory Outbursting Objects Key Project, as well as analysis of archival data in which 2023 RN3 was expected to be present. We find clear evidence of comet-like mass loss in the form of an extended morphology on UT 2023 November 16 and 18, and an increase in intrinsic brightness of >4 mag between 2022 September and 2023 November. We also report broadband colors for the coma of $g^{\prime} -r^{\prime} =0.61\pm 0.03$ , $r^{\prime} -i^{\prime} =0.30\pm 0.03$ , and $i^{\prime} -z^{\prime} =0.04\pm 0.08$ , giving a $g^{\prime} r^{\prime} i^{\prime} $ spectral slope of $S^{\prime} =(12\pm 2) \% $ /100 nm.

Keywords: comets; small solar system bodies; short period comets; centaur group; comae; sky surveys; observational astronomy; optical observation
Constraining Thermal Emission of Pluto's Haze from Infrared Rotational Lightcurves

The rotational lightcurves of the Pluto-Charon system were previously believed to be solely attributed to their surfaces. However, a proposed scenario of haze cooling suggests that the atmospheric haze of Pluto could significantly contribute to mid-infrared emission, which calls for a revisit of previous analyses. In this study, we employ a Bayesian retrieval approach to constrain the haze emission from the rotational lightcurves of the Pluto-Charon system. The lightcurves were observed by the Spitzer and Herschel telescopes at 24 and 70 μm, and were combined with the latest surface albedo maps of Pluto and Charon from the New Horizons spacecraft. Our results show that including the haze emission is consistent with all current observations, with the best-fit haze flux around 1.63 mJy. This is in agreement with the composition of Titan-like tholins. However, the "surface only" scenario, which excludes the haze contribution, can still explain the observations. We conclude that the current data at 24 μm cannot constrain Pluto's haze emission due to the degeneracy with Charon's surface emission. Regardless, some surface properties of Pluto are well constrained by the shape of the lightcurves, with a thermal inertia of approximately 8-10 MKS and a relatively low CH4 emissivity of 0.3-0.5. We suggest that observations by the JWST telescope at 18 μm, which can resolve Pluto from Charon, could directly probe the haze emission of Pluto due to the low surface emission at that wavelength.

Keywords: pluto
Robust Detrending of Spatially Correlated Systematics in Kepler Light Curves Using Low-rank Methods

Light curves produced by wide-field exoplanet transit surveys such as CoRoT, Kepler, and the Transiting Exoplanet Survey Satellite are affected by sensor-wide systematic noise, which is correlated both spatiotemporally and with other instrumental parameters such as the photometric magnitude. Robust and effective systematics mitigation is necessary to achieve the level of photometric accuracy required to detect exoplanet transits and to faithfully recover other forms of intrinsic astrophysical variability. We demonstrate the feasibility of a new exploratory algorithm to remove spatially correlated systematic noise and detrend light curves obtained from wide-field transit surveys. This spatial systematics algorithm is data-driven and fits a low-rank linear model for the systematics conditioned on a total-variation spatial constraint. The total-variation constraint models spatial systematic structure across the sensor on a foundational level. The fit is performed using gradient descent applied to, a variable reduced least-squares penalty and a modified form of total-variation prior; both the systematics basis vectors and their weighting coefficients are iteratively varied. The algorithm was numerically evaluated against a reference principal component analysis, using both signal injection on a selected Kepler dataset, as well as full simulations within the same Kepler coordinate framework. We develop our algorithm to reduce the overfitting of astrophysical variability over longer signal timescales (days) while performing comparably relative to the reference method for exoplanet transit timescales. The algorithm performance and application are assessed, and future development is outlined.

Keywords: exoplanet detection methods; astronomy data analysis; wide-field telescopes; surveys; transit photometry
A 99 minute Double-lined White Dwarf Binary from SDSS-V

We report the discovery of SDSS J133725.26+395237.7 (hereafter SDSS J1337+3952), a double-lined white dwarf (WD+WD) binary identified in early data from the fifth-generation Sloan Digital Sky Survey (SDSS-V). The double-lined nature of the system enables us to fully determine its orbital and stellar parameters with follow-up Gemini spectroscopy and Swift UVOT ultraviolet fluxes. The system is nearby (d = 113 pc), and consists of a 0.51 M⊙ primary and a 0.32 M⊙ secondary. SDSS J1337+3952 is a powerful source of gravitational waves in the millihertz regime, and will be detectable by future space-based interferometers. Due to this gravitational wave emission, the binary orbit will shrink down to the point of interaction in ≈220 Myr. The inferred stellar masses indicate that SDSS J1337+3952 will likely not explode as a Type Ia supernova (SN Ia). Instead, the system will probably merge and evolve into a rapidly rotating helium star and could produce an underluminous thermonuclear supernova along the way. The continuing search for similar systems in SDSS-V will grow the statistical sample of double-degenerate binaries across parameter space, constraining models of binary evolution and SNe Ia.

Keywords: white dwarf stars; da stars; spectroscopic binary stars; detached binary stars; gravitational wave sources
Cannonball or Bowling Ball: Proper Motion and Parallax for PSR J0002+6216

We report the results of careful astrometric measurements of the cannonball pulsar J0002+6216 carried out over 3 yr using the High Sensitivity Array. We significantly refine the proper motion to μ = 35.3 ± 0.6 mas yr-1 and place new constraints on the distance, with the overall effect of lowering the velocity and increasing the inferred age to 47.60 ± 0.80 kyr. Although the pulsar is brought more in line with the standard natal kick distribution, this new velocity has implications for the morphology of the pulsar wind nebula that surrounds it, the density of the interstellar medium through which it travels, and the age of the supernova remnant (CTB 1) from which it originates.

Keywords: supernova remnants; interstellar medium; pulsar wind nebulae; proper motions; pulsars; parallax; astrometry
Degradation of the Lunar Surface by Small Impacts

The surfaces of airless bodies like the Moon are bombarded by a steady stream of small impactors that lead to erosion of the topography over time. However, the rate of degradation from small impacts, a key parameter in interpreting the ages of present-day lunar surface features, is not well constrained. Here we demonstrate, using a numerical mass transport model, that impact erosion is a nonlinear diffusion process, in contrast to past studies of crater degradation that have assumed that the downslope mass flux of ejecta is linearly proportional to hillslope gradient. Nonlinearity is a consequence of the asymmetric shape of ejecta blankets on sloped surfaces, and as a result, the degradation rate on steep slopes is over 40% greater than on nearly flat surfaces. Using measurements of the morphology and formation rate of small primary and secondary craters, the kilometer-scale lunar landscape diffusivity is computed and compared to the value inferred from topographic profiles of degraded craters. We show that the abundance of decameter-scale craters forming on the Moon over the past decade is consistent with small impacts dominating the erosion of the lunar landscape, but only if the primary size-frequency distribution remains steep down to the submillimeter scale.

Keywords: the moon; lunar surface; lunar craters; impact phenomena; astronomical simulations
Fundamental-Harmonic Pairs of Interplanetary Type III Radio Bursts

Type III radio bursts are not only the most intense but also the most frequently observed solar radio bursts. However, a number of their defining features remain poorly understood. Observational limitations, such as a lack of sufficient spectral and temporal resolution, have hindered a full comprehension of the emission process, especially in the hectokilometric wavelengths. Of particular difficulty is the ability to detect the harmonics of type III radio bursts. Here we report the first detailed observations of type III fundamental-harmonic pairs in the hectokilometric wavelengths, observed by the Parker Solar Probe. We present a statistical analysis of the spectral characteristics and polarization measurements of the fundamental-harmonic pairs. Additionally, we quantify various characteristics of the fundamental-harmonic pairs, such as the time delay and time profile asymmetry. Our report concludes that fundamental-harmonic pairs constitute a majority of all type III radio bursts observed during close encounters when the probe is in close proximity to the source region and propagation effects are less pronounced.

Keywords: solar radio emission; solar electromagnetic emission; interplanetary turbulence; interplanetary physics
Large Sunspot Groups and Great Magnetic Storms: Magnetic Suppression of CMEs

A solar spot group with a large area is not a requirement for a great magnetic storm. Nearly half (14/30) of all storms with a minimum Dst value ≤-300 nT from 1932-2014 originated in spot groups with corrected areas ≤1000 millionths of a solar hemisphere (μsh) on the day of the associated eruption. Over the same interval, spot groups with area 3000-4000 μsh were ~250 times more likely to give rise to a great storm than those with areas from 100-1000 μsh, with the high percentage of great storms originating in small spot groups attributed primarily to the much higher occurrence frequency of such groups. Above ~3500 μsh, the ability of a spot group to produce a great storm appears to drop abruptly. For the 1932-2014 interval, we find that for the 71 days when a spot group had a measured daily area of 3000-3500 μsh, five great storms were observed versus none for the 67 times when a group spot with an area from 3500 to ~6000 μsh was observed on the Sun. This is consistent with recent studies indicating that large spot groups on the Sun and stars can suppress coronal mass ejections.

Keywords: sunspot groups; solar active regions; solar activity; solar flares; solar filament eruptions; solar coronal mass ejections; space weather; solar-terrestrial interactions
Are Nonthermal Velocities in Active Region Coronal Loops Anisotropic?

We have measured line widths in active region coronal loops in order to determine whether the nonthermal broadening is anisotropic with respect to the magnetic field direction. These nonthermal velocities are caused by unresolved fluid motions. Our analysis method combines spectroscopic data and a magnetic field extrapolation. We analyzed spectra from the Extreme Ultraviolet Imaging Spectrometer on Hinode. A differential emission measure analysis showed that many spectral lines that are commonly considered to be formed in the active region have a substantial contribution from the background quiet Sun. From these spectra we identified lines whose emission was dominated by the active region loops rather than background sources. Using these lines, we constructed maps of the nonthermal velocity. With data from the Helioseismic Magnetic Imager on the Solar Dynamics Observatory and the Coronal Modeling System nonlinear force-free magnetic field reconstruction code, we traced several of the magnetic field lines through the active region. Comparing the spectroscopic and magnetic data, we looked for correlations of the nonthermal velocity with the viewing angle between the line of sight and the magnetic field. We found that nonthermal velocities show a weak anticorrelation with the viewing angle. That is, the tendency is for the nonthermal velocity to be slightly larger in the parallel direction. This parallel broadening may be due to acoustic waves or unresolved parallel flows.

Keywords: solar coronal heating; solar coronal loops; active solar corona; quiet solar corona; solar coronal waves; solar coronal lines; ultraviolet spectroscopy
Prospects for Extending the Core-collapse Supernova Detection Horizon Using High-energy Neutrinos

Large neutrino detectors like IceCube monitor for core-collapse supernovae using low-energy (MeV) neutrinos with a detection reach from a supernova neutrino burst to the Magellanic Cloud. However, some models predict the emission of high-energy neutrinos of GeV-TeV from core-collapse supernovae through the interaction of ejecta with circumstellar material with energies of TeV-PeV produced through choked jets. In this paper, we explore the detection horizon of IceCube for core-collapse supernovae using high-energy neutrinos from these models. We examine the potential of two high-energy neutrino data samples from IceCube, one that performs best in the northern sky and one that has better sensitivity in the southern sky. We demonstrate that, by using high-energy neutrinos from core-collapse supernovae, the detection reach can be extended to the megaparsec range, far beyond what is accessible through low-energy neutrinos. Looking ahead to IceCube-Gen2, this reach will be extended considerably.

Keywords: high energy astrophysics; supernova neutrinos; cosmological neutrinos; particle astrophysics; neutrino telescopes; core-collapse supernovae
Interstellar Polarization Survey. III. Relation between Optical Polarization and Reddening in the General Interstellar Medium

Optical starlight can be partially polarized while propagating through the dusty, magnetized interstellar medium (ISM). The polarization efficiency describes the polarization intensity fraction per reddening unit, P V /E(B - V), related to the interstellar dust grains and magnetic field properties. The maximum value observed, [P V /E(B - V)]max, is thus achieved under optimal polarizing conditions of the ISM. Therefore, the analysis of polarization efficiency observations across the Galaxy contributes to the study of magnetic field topology, small-scale magnetic fluctuations, grain-alignment efficiency, and composition. Infrared observations from Planck satellite have set [P V /E(B - V)]max to 13% mag-1. However, recent optical polarization observations in Planck's highly polarized regions showed polarization efficiency values between 13.6% mag-1 and 18.2% mag-1 (depending on the extinction map used), indicating that [P V /E(B - V)]max is not well constrained yet. We used V-band polarimetry of the Interstellar Polarization Survey (consisting of ~10,500 high-quality observations distributed in 34 fields of 0.°3 × 0.°3) to accurately estimate the polarization efficiency in the ISM. We estimated the upper limit of P V /E(B - V) with the weighted 99th percentile of the field. In five regions, the polarization efficiency upper limit is above 13% mag-1. Furthermore, we found [P V /E(B - V)] ${}_{\max }={15.8}_{-0.9}^{+1.3}$ % mag-1 using diffuse intermediate-latitude (∣b∣ > 7.°5) regions with apparently strong regular Galactic magnetic field in the plane-of-sky. We studied the variations of P V /E(B - V) across the sky and tested toy models of polarization efficiency with Galactic longitude that showed some correspondence with a uniform spiral magnetic field.

Keywords: starlight polarization; optical observation; interstellar medium; interstellar magnetic fields; interstellar dust; interstellar dust extinction
Joint Action and Competition between Centrifugal, Magnetorotational, and Magnetic Buoyancy Instabilities

Instabilities driven by some combination of rotation, velocity shear, and magnetic field in a stratified fluid under gravity play an important role in many astrophysical settings. Of particular note are the centrifugal instability, the magnetorotational instability, and magnetic buoyancy instability. Here, we consider a Cartesian model of an equatorial region incorporating all the physical ingredients necessary to study their competition. We investigate the linear instability to interchange ("axisymmetric") modes of an inviscid, perfectly conducting, isothermal gas, including the effects of rotation, velocity shear, and poloidal and toroidal magnetic fields. The stability problem can be reduced to a second-order boundary value problem, with the growth rate as the eigenvalue. We can make analytic progress through consideration of the physically relevant regime in which the transverse horizontal wavenumber k ≫ 1. Via a perturbation analysis, with 1/k as the small parameter, we can derive the growth rate and the spatial dependence of the eigenfunctions: the unstable modes are strongly localized in the vertical direction, being either wall modes (localized near a boundary of the domain) or body modes (localized in the interior). We describe the conditions under which the joint action of the separate instability mechanisms leads to enhancement or suppression of the instability. Our analytical results are supplemented by numerical solutions of the stability problem. The most unstable mode found analytically is typically in excellent agreement with that found numerically through consideration of a wide range of wavenumbers. Finally, we discuss how our results relate to the solar tachocline.

Keywords: magnetohydrodynamics; solar magnetic fields; perturbation methods
Morphological Evidence for the eROSITA Bubbles Being Giant and Distant Structures

There are two contradictory views of the eROSITA bubbles: either a 104 pc scale pair of giant bubbles blown by the Galactic center (GC), or a 102 pc scale local structure coincidentally located in the direction of GC. A key element of this controversy is the distance to the bubbles. Based on the 3D dust distribution in the Galactic plane, we found three isolated, distant (500–800 pc) clouds at intermediate Galactic latitudes. Their projected morphologies perfectly match the X-ray shadows on the defining features of the north eROSITA bubble, i.e., the North Polar Spur (NPS) and the Lotus Petal Cloud (LPC), indicating that both the NPS and LPC are distant, with a distance lower limit of nearly 1 kpc. In the X-ray-dark region between the NPS and LPC, we found a few polarized radio arcs and attributed them to the bubble's shock front. These arcs match up perfectly with the outer border of the NPS and LPC and provide a way to define the bubble's border. The border defined in this way can be well described by the line-of-sight tangent of a 3D skewed cup model rooted in the GC. We conclude that, instead of being two independent, distant features, the NPS and LPC compose a single, giant bubble, which therefore is most plausibly a 10 kpc scale bubble rooted at the GC.

Keywords: milky way galaxy; interstellar clouds; diffuse interstellar clouds; shocks; x-ray surveys; active galactic nuclei; jets; dark interstellar clouds; interstellar dust extinction