adsabs/SciX_UAT_keywords huggingface dataset:
ARMADA. II. Further Detections of Inner Companions to Intermediate-mass Binaries with Microarcsecond Astrometry at CHARA and VLTI

We started a survey with CHARA/MIRC-X and VLTI/GRAVITY to search for low-mass companions orbiting individual components of intermediate-mass binary systems. With the incredible precision of these instruments, we can detect astrometric "wobbles" from companions down to a few tens of microarcseconds. This allows us to detect any previously unseen triple systems in our list of binaries. We present the orbits of 12 companions around early F- to B-type binaries, 9 of which are new detections and 3 of which are first astrometric detections of known radial velocity (RV) companions. The masses of these newly detected components range from 0.45 to 1.3 M ⊙. Our orbits constrain these systems to a high astrometric precision, with median residuals to the orbital fit of 20-50 μas in most cases. For seven of these systems we include newly obtained RV data, which help us to identify the system configuration and to solve for masses of individual components in some cases. Although additional RV measurements are needed to break degeneracy in the mutual inclination, we find that the majority of these inner triples are not well aligned with the wide binary orbit. This hints that higher-mass triples are more misaligned compared to solar and lower-mass triples, though a thorough study of survey biases is needed. We show that the ARMADA survey is extremely successful at uncovering previously unseen companions in binaries. This method will be used in upcoming papers to constrain companion demographics in intermediate-mass binary systems down to the planetary-mass regime.

Keywords: astrometric binary stars; multiple stars; astrometry; long baseline interferometry; trinary stars; spectroscopic binary stars
The Stellar Abundances and Galactic Evolution Survey (SAGES). I. General Description and the First Data Release (DR1)

The Stellar Abundances and Galactic Evolution Survey (SAGES) of the northern sky is a specifically designed multiband photometric survey aiming to provide reliable stellar parameters with accuracy comparable to those from low-resolution optical spectra. It was carried out with the 2.3 m Bok telescope of Steward Observatory and three other telescopes. The observations in the u s and v s passband produced over 36,092 frames of images in total, covering a sky area of ~9960 deg2. The median survey completenesses of all observing fields for the two bands are u s = 20.4 mag and v s = 20.3 mag, respectively, while the limiting magnitudes with signal-to-noise ratio of 100 are u s ~ 17 mag and v s ~ 18 mag, correspondingly. We combined our catalog with the data release 1 (DR1) of the first Panoramic Survey Telescope And Rapid Response System (Pan-STARRS, PS1) catalog, and obtained a total of 48,553,987 sources that have at least one photometric measurement in each of the SAGES u s and v s and PS1 grizy passbands. This is the DR1 of SAGES, released in this paper. We compared our gri point-source photometry with those of PS1 and found an rms scatter of ~2% difference between PS1 and SAGES for the same band. We estimated an internal photometric precision of SAGES to be of the order of ~1%. Astrometric precision is better than 0.″2 based on comparison with DR1 of the Gaia mission. In this paper, we also describe the final end-user database, and provide some science applications.

Keywords: galactic archaeology; milky way galaxy physics
The Mira Distance to M101 and a 4% Measurement of H 0

The giant spiral galaxy M101 is host to the nearest recent Type Ia supernova (SN 2011fe) and thus has been extensively monitored in the near-infrared to study the late-time light curve of the SN. Leveraging this existing baseline of observations, we derive the first Mira-based distance to M101 by discovering and classifying a sample of 211 Miras with periods ranging from 240–400 days in the SN field. Combined with new Hubble Space Telescope (HST) WFC3/IR channel observations, our data set totals 11 epochs of F110W (HST YJ) and 13 epochs of F160W (HST H) data spanning ∼2900 days. We adopt absolute calibrations of the Mira period–luminosity relation based on geometric distances to the Large Magellanic Cloud and the water megamaser host galaxy NGC 4258, and find μ M101 = 29.10 ± 0.06 mag. This distance is in 1σ agreement with most other recent Cepheid and tip of the red giant branch distance measurements to M101. Including the previous Mira SN Ia host, NGC 1559, and SN 2005df, we determine the fiducial SN Ia peak luminosity, ${M}_{B}^{0}=-19.27\,\pm \,0.09$ mag. With the Hubble diagram of supernovae Ia, we derive H 0 = 72.37 ± 2.97 km s‑1 Mpc‑1, a 4.1% measurement of H 0 using Miras. We find excellent agreement with recent Cepheid distance ladder measurements of H 0 and confirm previous indications that the local universe value of H 0 is higher than the early universe value at ∼95% confidence. Currently, the Mira-based H 0 measurement is still dominated by the statistical uncertainty in the SN Ia peak magnitude.

Keywords: observational cosmology; mira variable stars; asymptotic giant branch stars; hubble constant; stellar distance; distance indicators; type ia supernovae; galaxy distances
Mapping "Brain Terrain" Regions on Mars Using Deep Learning

One of the main objectives of the Mars Exploration Program is to search for evidence of past or current life on the planet. To achieve this, Mars exploration has been focusing on regions that may have liquid or frozen water. A set of critical areas may have seen cycles of ice thawing in the relatively recent past in response to periodic changes in the obliquity of Mars. In this work, we use convolutional neural networks to detect surface regions containing "brain terrain," a landform on Mars whose similarity in morphology and scale to sorted stone circles on Earth suggests that it may have formed as a consequence of freeze/thaw cycles. We use large images (∼100–1000 megapixels) from the Mars Reconnaissance Orbiter to search for these landforms at resolutions close to a few tens of centimeters per pixel (∼25–50 cm). Over 58,000 images (∼28 TB) were searched (∼5% of the Martian surface), and we found detections in 201 images. To expedite the processing, we leverage a classifier network (prior to segmentation) in the Fourier domain that can take advantage of JPEG compression by leveraging blocks of coefficients from a discrete cosine transform in lieu of decoding the entire image at the full spatial resolution. The hybrid pipeline approach maintains ∼93% accuracy while cutting down on ∼95% of the total processing time compared to running the segmentation network at the full resolution on every image.

Keywords: mars; planetary surfaces; remote sensing
SOFIA-EXES Observations of Betelgeuse during the Great Dimming of 2019/2020

In 2019 October Betelgeuse began a decline in V-band brightness that went beyond the minimum expected from its quasi-periodic ∼420 day cycle, becoming the faintest in recorded photometric history. Observations obtained in 2019 December with Very Large Telescope/SPHERE have shown that the southern half of the star has become markedly fainter than in 2019 January, indicating that a major change has occurred in, or near, the photosphere. We present Stratospheric Observatory for Infrared Astronomy (SOFIA) Echelon Cross Echelle Spectrograph (EXES) high spectral-resolution observations of [Fe II] $25.99\,\mu {\rm{m}}$ and [S I] $25.25\,\mu {\rm{m}}$ emission lines from Betelgeuse obtained during the unprecedented 2020 February V-band brightness minimum to investigate potential changes in the circumstellar flow. These spectra are compared to observations obtained in 2015 and 2017 when the V magnitude was typical of brighter phases. We find only very small changes in the gas velocities reflected by either of the line profiles, no significant changes in the flux to continuum ratios, and hence no significant changes in the [Fe II]/[S I] flux ratios. There is evidence that absorption features have appeared in the 2020 continuum. The Alfvén wave-crossing time from the upper photosphere is sufficiently long that one would not expect a change in the large-scale magnetic field to reach the circumstellar [Fe II] and [S I] line-forming regions, 3 < R (R*) < 20. However, the light-crossing time is of order a few hours and a reduction in luminosity may reduce the dust-gas heating rate and [O I] $63.19\,\mu {\rm{m}}$ emission, which has contributions from R > 20R*, where significant circumstellar oxygen-rich dust is observed.

Keywords: supergiant stars; circumstellar envelopes; stellar mass loss; stellar spectral lines
Condensation of Glass with Multimetal Nanoparticles: Implications for the Formation Process of GEMS Grains

Interplanetary dust particles contain grains of glass with embedded metals and sulfides (GEMS; i.e., amorphous silicate grains with diameters of a few hundred nanometers containing Fe nanoinclusions and Fe sulfide particles), which are considered to be among the building blocks of the solar system. To explore that GEMS grains formed during the condensation process, condensation experiments were carried out in Si-Mg-Fe-Al-Ca-Ni-O and Mg-Si-Fe-Ca-Al-Na-O systems using an induction thermal plasma furnace. In all experimental runs, spherical grains (mostly composed of amorphous silicate) with diameter <100 nm formed. The analysis of the amorphous silicates, which were classified as Mg rich or Si rich, indicated that the condensates formed via melting. Fe led to the formation of fine magnetite grains in most of the oxidative experiments, to 10 nm metal grains (i.e., kamacite and taenite) under intermediate redox conditions, and to 30-100 nm Fe silicide grains (i.e., gupeiite, xifengite, and fersilicite) in most of the reductive experiments. Under intermediate redox conditions, some amorphous silicate particles showed multiple Fe inclusions with textures very similar to those of GEMS grains except for FeS, indicating that GEMS could form via melt condensation of high-temperature gases. Considering the nucleation and growth of solids from high-temperature gas during cooling, we infer that GEMS grains form either in the local environment of a protosolar disk (and be related to chondrule formations) or around evolved stars related to Type II-P supernovae and asymptotic giant branch-type stars.

Keywords: interplanetary dust; laboratory astrophysics; silicate grains
The Fundamental Plane Relation for Gamma-Ray Pulsars Implied by 4FGL

We explore the validity of the recently reported fundamental plane (FP) relation of γ-ray pulsars using 190 pulsars included in the latest 4FGL-DR3 catalog. This sample number is more than twice as large as that of the original study. The FP relation incorporates four parameters, i.e., the spin-down power, $\dot{{ \mathcal E }}$ , the surface magnetic field, B ⋆, the total γ-ray luminosity, L γ , and a spectral cutoff energy, ϵ cut. The derivation of ϵ cut is the most intriguing one because ϵ cut depends on the proper interpretation of the available phase-averaged spectra. We construct synthetic phase-averaged spectra, guided by the few existing phase-resolved ones, to find that the best-fit cutoff energy, ϵ c1, corresponding to a purely exponential cutoff (plus a power-law) spectral form, is the parameter that optimally probes the maximum cutoff energy of the emission that originates from the core of the dissipative region, i.e., the equatorial current sheet. Computing this parameter for the 190 4FGL pulsars, we find that the resulting FP relation, i.e., the γ-ray luminosity in terms of the other observables, reads as ${L}_{\gamma }={10}^{14.3\pm 1.3}{({\epsilon }_{{\rm{c}}1}/\mathrm{MeV})}^{1.39\pm 0.17}$ ${({B}_{\star }/{\rm{G}})}^{0.12\pm 0.03}{(\dot{{ \mathcal E }}/\mathrm{erg}\,{{\rm{s}}}^{-1})}^{0.39\pm 0.05}\,\mathrm{erg}\,{{\rm{s}}}^{-1};$ this is in good agreement with both the empirical relation reported by Kalapotharakos et al. and the theoretically predicted relation for curvature radiation. Finally, we revisit the radiation reaction limited condition, to find it is a sufficient but not necessary condition for the theoretical derivation of the FP relation. However, the assumption of the radiation reaction limited acceleration reveals the underlying accelerating electric field component and its scaling with $\dot{{ \mathcal E }}$ .

Keywords: pulsars; gamma-rays; gamma-ray telescopes
Estimating Ion Temperatures at the Polar Coronal Hole Boundary

The temperatures of the heavy ions (T i ) in the solar corona provide critical information about the heating mechanism of the million-degree corona. However, the measurement of T i is usually challenging due to the nonthermal motion, instrumental limitations, and optically thin nature of the coronal emissions. We present the measurement of T i and its dependency on the ion charge-to-mass ratio (Z/A) at the polar coronal hole boundary, only assuming that heavy ions have the same nonthermal velocity. To improve the Z/A coverage and study the influence of the instrumental broadening, we used a coordinated observation from the EUV Imaging Spectrometer on board the Hinode satellite and the Solar Ultraviolet Measurements of Emitted Radiation (SUMER) on board the Solar and Heliospheric Observatory. We found that the T i of ions with Z/A less than 0.20 or greater than 0.33 are much higher than the local electron temperature. We ran the Alfvén Wave Solar Model-realtime to investigate the formation of optically thin emissions along the line of sight (LOS). The simulation suggested that plasma bulk motions along the LOS broaden the widths of hot emission lines in the coronal hole (e.g., Fe XII, Fe XIII). We discussed other factors that might affect the T i measurement, including the non-Gaussian wings in some bright SUMER lines, which can be fitted by a double-Gaussian or a κ distribution. Our study confirms the preferential heating of heavy ions in coronal holes and provides new constraints on coronal heating models.

Keywords: solar coronal holes; solar coronal lines; solar coronal heating; spectroscopy
Solar Cycle 25 Will Be a Weak-moderate Cycle: an Update

We have previously published several research notes analyzing the solar activity level of current Solar Cycle 25 from the observed sunspot data. pointing out that it exhibits the typical behavior of a weak-moderate cycle. We show in this updated analysis of the solar activity level for Solar Cycle 25 (three year after its beginning) that the current cycle continues being a weak-moderate cycle with values slightly higher than the previous Solar Cycle 24, which was a weak cycle. We also compare the observed sunspot data available until 2023 June with the prediction made by the Solar Cycle 25 Prediction Panel. As conclusion, it seems likely that Solar Cycle 25 will continue to be a weak-moderate one.

Keywords: sunspot number; solar activity; solar cycle
A Compilation of Pulse Widths and Their Associated Observing Parameters for All Known Nulling Pulsars

Nulling pulsars are pulsars whose observed flux occasionally disappears, but the mechanism behind the cessation is not well understood. Motivated by the correlation between pulse width and nulling fraction found in Sheikh & MacDonald, we compile all 378 nulling pulsars to date with their pulse widths in a machine-readable table. We also include the observing frequency and time resolution of each pulse width measurement. Such a table will be useful for future studies of this population.

Keywords: pulsars; radio source catalogs
Science-rich Sites for In Situ Resource Utilization Characterization and End-to-end Demonstration Missions

Within the European Space Agency's "Commercial In Situ Resource Utilization (ISRU) Demonstration Mission Preparation Phase," we examined two types of lunar sites in preparation for an ISRU demonstration mission. First, we considered poorly characterized potential resource sites. For these so-called characterization sites, precursor missions would investigate the material properties and address strategic knowledge gaps for their use as ISRU feedstock. Regions of interest for characterization missions include the Aristarchus plateau, Montes Harbinger/Rimae Prinz, Sulpicius Gallus, and Rima Bode. Regional pyroclastic deposits at the Aristarchus plateau and adjacent Montes Harbinger/Rimae Prinz exhibit remotely sensed low-Ti, high-Fe2+ compositions. They differ from the high-Ti pyroclastics at Rima Bode and Sulpicius Gallus, which are similar to the pyroclastics northwest of the Taurus Littrow valley (Apollo 17 site). Thus, exploration of the Aristarchus plateau would allow investigation of previously uncharacterized materials, whereas Rima Bode or Sulpicius Gallus would allow comparison to Apollo 17 pyroclastics. Any of these sites would enable evaluation of reported H2O/OH in these deposits. Second, we examined a possible site for a direct ISRU demonstrator mission. For a stand-alone end-to-end (E2E) ISRU demonstrator, a fuller understanding of the physical and compositional characteristics of potential feedstock is required for mission risk reduction. In this case, locations near preexisting sites would allow extrapolation of ground truth to nearby deposits. Because a Ti-rich pyroclastic deposit appears advantageous from beneficiation and compositional perspectives, we examine an example E2E demo site northwest of the Taurus Littrow valley. Hydrogen and methane reduction, as well as the Fray-Farthing-Chen Cambridge process, could be tested there.

Keywords: lunar science; lunar surface
Pulsar Timing Noise from Brownian Motion of the Sun

Recently, pulsar timing arrays (PTAs) reported a signal at nanohertz frequencies consistent with a stochastic gravitational-wave background. Here, I show that the Brownian motion of the Sun as a result of its random gravitational interactions with the cluster of thousands of unmodeled main-belt asteroids of diameters ≲80 km, combined with small inaccuracies in the estimated masses of larger asteroids, introduces timing noise for pulsars, which is up to 20% of the reported signal at frequencies of ∼1 few years–1. The asteroid contribution needs to be modeled better in order to obtain accurate inferences from the PTA signal.

Keywords: asteroid belt; gravitational wave astronomy
Discriminating between Babcock–Leighton-type Solar Dynamo Models by Torsional Oscillations

The details of the dynamo process in the Sun are an important aspect of research in solar-terrestrial physics and astrophysics. The surface part of the dynamo can be constrained by direct observations, but the subsurface part lacks direct observational constraints. The torsional oscillations, a small periodic variation of the Sun's rotation with the solar cycle, are thought to result from the Lorentz force of the cyclic magnetic field generated by the dynamo. In this study, we aim to discriminate between three Babcock–Leighton dynamo models by comparing the zonal acceleration of the three models with the observed one. The property that the poleward and equatorward branches of the torsional oscillations originate from about ±55° latitudes with their own migration time periods serves as an effective discriminator that could constrain the configuration of the magnetic field in the convection zone. The toroidal field, comprising poleward and equatorward branches separated at about ±55° latitudes, can generate the two branches of the torsional oscillations. The alternating acceleration and deceleration bands in time are the other property of the torsional oscillations that discriminates between the dynamo models. To reproduce this property, the phase difference between the radial (B r ) and toroidal (B ϕ ) components of the magnetic field near the surface should be about π/2.

Keywords: solar cycle; solar magnetic fields; helioseismology; solar differential rotation; solar dynamo
Active Region Irradiance during Quiescent Periods: New Insights from Sun-as-a-star Spectra

How much energy do solar active regions (ARs) typically radiate during quiescent periods? This is a fundamental question for storage and release models of flares and ARs, yet it is presently poorly answered by observations. Here we use the "Sun-as-a-point-source" spectra from the EUV Variability Experiment (EVE) on the Solar Dynamics Observatory to provide a novel estimate of radiative energy losses of an evolving AR. Although EVE provides excellent spectral (5-105 nm) and temperature (2-25 MK) coverage for AR analysis, to our knowledge, these data have not been used for this purpose due to the lack of spatial resolution and the likelihood of source confusion. Here we present a way around this problem. We analyze EVE data time series, when only one large AR 11520 was present on the disk. By subtracting the quiet-Sun background, we estimate the radiative contribution in EUV from the AR alone. We estimate the mean AR irradiance and cumulative AR radiative energy losses in the 1-300 Å and astronomical standard ROSAT-PSPC, 3-124 Å, passbands and compare these to the magnetic energy injection rate through the photosphere, and to variations of the solar cycle luminosity. We find that while AR radiative energy losses are ∼100 times smaller than typical magnetic energy injection rates at the photosphere, they are an order of magnitude larger or similar to the bolometric radiated energies associated with large flares. This study is the first detailed analysis of AR thermal properties using EVE Sun-as-a-star observations, opening doors to AR studies on other stars.

Keywords: solar active regions; active solar corona; solar spectral irradiance; solar activity; solar physics; solar coronal lines; solar active region magnetic fields; stellar activity; solar atmosphere; solar flares; solar flare spectra; stellar spectral lines
Observational Constraints on the Physical Properties of Interstellar Dust in the Post-Planck Era

We present a synthesis of the astronomical observations constraining the wavelength-dependent extinction, emission, and polarization from interstellar dust from UV to microwave wavelengths on diffuse Galactic sight lines. Representative solid-phase abundances for those sight lines are also derived. Given the sensitive new observations of polarized dust emission provided by the Planck satellite, we place particular emphasis on dust polarimetry, including continuum polarized extinction, polarization in the carbonaceous and silicate spectroscopic features, the wavelength-dependent polarization fraction of the dust emission, and the connection between optical polarized extinction and far-infrared polarized emission. Together, these constitute a set of constraints that should be reproduced by models of dust in the diffuse interstellar medium.

Keywords: dust continuum emission; interstellar dust; interstellar dust extinction; starlight polarization; polycyclic aromatic hydrocarbons; silicate grains; interstellar scattering