Sazuna/UAT_keywords huggingface dataset:
Estimating Aerodynamic Properties of Planetary Surfaces using Drone Attitude. Measuring the wind profile near a planet's surface provides a way to estimate friction velocity and the surface's aerodynamic roughness length, parameters key for understanding and predicting aeolian activity. In this study, we demonstrate the feasibility of measuring the wind profile using only the attitude of a small drone. Such an approach may be particularly advantageous in planetary exploration where instrument payload, data volume, and power are all limited. Indeed, estimates of Martian winds and the wind profile are likely already feasible with telemetry from Mars 2020 Ingenuity. Given the enormous influence of wind in energy and sediment redistribution on Mars, such measurements are critical to understanding aeolian processes and to constraining parameters used in geologic and climate models (such as dust lofting rates). Future work should explore how to expand on and improve the measurement approach discussed here and whether the already collected telemetry from Ingenuity might be used.

Keywords: Planetary atmospheres
Updated Spectral Type Polynomials for Ultracool Dwarfs with CatWISE Photometry. Using a volume-limited sample of 263 field-age brown dwarfs defined by parallaxes, we provide updated polynomials for CatWISE W1 and W2 absolute magnitudes as a function of spectral type. Our fits are consistent with previous relations and apply to a wider M6-Y1 spectral type range.

Keywords: Surveys, Low mass stars, Brown dwarfs, Astrometry
Is there a Radio Excess from the Decoupling of Pre-recombination Bremsstrahlung?. Recently it has been suggested that thermal bremsstrahlung emission, when it decouples prior to recombination, creates an excess over the Planck cosmic microwave background spectrum at sub-GHz frequencies. Remarkable by itself, this would also explain a long-standing unexplained deficit in the predictions of the extragalactic radio background. In this brief note, I reiterate that no such non-thermal component can arise by itself when matter and radiation remain kinetically coupled.

Keywords: Cosmic microwave background radiation, Radiative processes
The Behavior of HgMn Stars in the Far UV-Paper 21: HD 29589. The analysis of two spectra of the Mn Hg star HD 29589 recorded by the SWP camera on board the International Ultraviolet Explorer does not reveal variations of the far-ultraviolet flux over a thirteen years time interval. The TESS lightcurve of HD 29589 shows a complex pattern of oscillations with variable amplitudes and probably several periods. A very strong resonance line of Ga II is present at 1414.40 Å and confirms the Hg Mn status of HD 29589. A P Cygni profile at 1793.20 Å on SWP04948 could correspond to the resonance line of Sr II at 1793.09 Å and indicate transient mass loss.

Keywords: Mercury-manganese stars, Chemically peculiar stars
A VLA Light Curve Spanning 43.8 yr for the Compact Symmetric Object OQ 208. Compact symmetric objects are young, jetted active galactic nuclei defined in part by their slow radio continuum variability. Radio light curves spanning decades can help characterize their evolutionary trends. Here, we present a preliminary VLA light curve at 1.465 GHz for the compact symmetric object OQ 208, a frequently observed calibrator. The light curve spans 43.8 yr, or about 17% of OQ 208's estimated age. The light curve shows two distinct steady levels separated by a decade-long rise at a rate of about 1% yr-1, corresponding to a cumulative increase of about 12% in flux density.

Keywords: Aperture synthesis, Radio jets, Active galactic nuclei, Time domain astronomy, Radio continuum emission
Photometric BVR Observations of (65803) Didymos after DART. The near-Earth binary asteroid Didymos was observed by robotic telescopes in Australia, Chile, and the United States three to five weeks after its impact with the DART spacecraft. The B - R spectral slope of the Didymos system was 13% ± 1%/100 nm, redder than that of the Sun, active comets, and its previously measured colors. The dust cloud around the Didymos system caused a mean drop of 0.29 ± 0.08 mag and had an optical thickness of 0.27 ± 0.07, based on observations from October 27.743 and 28.740 UT. The mean FWHM of the photometric profile of the Didymos system was 1.1 ± 0.1 larger than that of the unsaturated field stars in the R band during our observing campaign. According to our results, the B - R color index was the best parameter to detect the activity of this asteroid in the visible range.

Keywords: Near-Earth objects, Apollo group, Asteroids, Multi-color photometry
Spectral Characterization of the Low-mass Companion μ Virgenes B. We report optical and near-infrared spectral characterization of an M dwarf companion to the bright F2 star μ Virgenes. Data from Shane/Kast and IRTF/SpeX yield identical spectral types of M5, and spectral features indicate solar metallicity ([Fe/H] = -0.05 ± 0.20) with no evidence of low surface gravity features at optical or near-infrared bands. Strong Hα emission ( ${\mathrm{log}}_{10}{L}_{{\rm{H}}\alpha }/{L}_{\mathrm{bol}}$ = -3.80 ± 0.09) is consistent with an active source at saturation, while the lack of Li I absorption and low surface gravity features constrains the system's age to ≳200 Myr. Both metallicity and age estimates of the companion are consistent with its primary. As a well-resolved companion to an exceptionally well-characterized bright star, μ Virgenes B serves as a useful benchmark at the transition between partially and fully convective stars.

Keywords: M dwarf stars, Stellar classification, Solar neighborhood, Companion stars
Small Magellanic Cloud Field Stars Meddling in Star Cluster Age Estimates. I revisited the age of the Small Magellanic Cloud (SMC) cluster HW 42, whose previous estimates differ in more than 6 Gyr, thus challenging the most updated knowledge of the SMC star formation history. I performed an analysis of number stellar density profiles at different brightness levels; carried out a field star decontamination of the cluster color-magnitude diagram; and estimated the cluster fundamental parameters from the minimization of likelihood functions and their uncertainties from standard bootstrap methods. I conclude that HW 42 is a ${6.2}_{-1.3}^{+1.6}$ Gyr old ([Fe/H] = -0.89 ${}_{-0.11}^{+0.10}$ dex) SMC cluster projected on to a SMC composite star field population which shows variations in magnitude, color, and stellar density of Main Sequence stars. The present outcome solves the conundrum of the previous age discrepancies and moves HW 42 to a region in the SMC age-metallicity relationship populated by star clusters.

Keywords: Astronomical techniques, Small Magellanic Cloud, Star clusters
TrExoLiSTS: Transiting Exoplanets List of Space Telescope Spectroscopy. We present the Space Telescope Science Institute Wide Field Camera 3 (WFC3) project webpage, Transiting Exoplanets List of Space Telescope Spectroscopy, TrExoLiSTS. It tabulates existing observations of transiting exoplanet atmospheres, available in the MAST archive made with Hubble Space Telescope (HST) WFC3 using the stare or spatial scan mode. A parallel page is available for all instruments aboard James Webb Space Telescope (JWST) using the spectral Time Series Observation mode. The webpages include observations obtained during primary transits, secondary eclipses and phase curves. TREXOLISTS facilitates proposal preparation for programs that are highly complementary to existing programs in terms of targets, wavelength coverage, as well as reduces duplication and redundant effort. Reference for the quality of the HST WFC3 visits taken more than 1.5 yr ago are made available via including diagrams of the direct image, white light curve and drift of the spectral time series across the detector. Future improvements to the webpage will include: Expanding program query to other HST instruments and reference for the quality of JWST visits.

Keywords: Observational astronomy, Exoplanet atmospheres, Exoplanet catalogs, Catalogs
The Behavior of HgMn Stars in the Far UV-Paper 23: HD 144844. The analysis of four high resolution spectra of the Mn P Ga star HD 144844 recorded by the SWP camera on board the International Ultraviolet Explorer does not reveal variations of the far ultraviolet flux of this star from 1994 July 1st to July 12th. The IUE spectra sample four different rotational phases of the rotational period derived recently from the Kepler lightcurve which shows that the far ultraviolet flux of HD 144844 is not modulated by rotation. However a previous low resolution SWP spectrum taken in August 1989 has significantly more FUV flux shortwards of 1700 Å than the spectra collected in 1994 July. On the the first spectrum of the 1994 July observations, the Al II resonance line at 1670.79 Å is split into two components probably reflecting the orbital motions of HD 144844 and its companion.

Keywords: Helium-weak stars, Chemically peculiar stars
A Multiwavelength Study of the Ongoing Changing-look AGN AT2021fxu. We present multiwavelength analyses of an active optical transient AT2021fxu which shows the appearance of previously absent broad emission lines in a recent optical spectrum, suggesting a Changing-look Active Galactic Nucleus (AGN). During the spectral transition, the brightness in the individual photometric bands increased up to ≈0.6 in the optical bands and up to ≈1.1 mag in the UV bands. The brightening was accompanied by a blueward shift of the optical spectrum. AT2021fxu shows high X-ray (0.3-10 keV) flux variability before and after the outburst, with the average X-ray flux increasing by a factor of ≈2 post-outburst. However, the X-ray spectral shape remains roughly the same, with no significant change in the line-of-sight column density. AT2021fxu's overall properties are consistent with an accretion-rate-driven transition from a Type-II to a Type-1 AGN.

Keywords: Optical bursts, Active galactic nuclei, Transient sources
HD 345723: RS Canum Venaticorum Variable Star Detected with TESS Data. This study describes the nature of HD 345723, a variable star identified in TESS photometric data. Analyzing the light curve, we obtain a period of 19 hr and 17 minutes in phase domain. The star, a K6 spectral class, suggest that the variation is due to the presence of large stellar spots in a very close binary system, detected by GAIA spectrum. The double star, at coordinates R.A. (J2000) 20:06:51.33 and decl. (J2000) +22:39:51.7, has a distance of 719 pc, according to reliable GAIA parallax measurements.

Keywords: RS Canum Venaticorum variable stars, Magnetic stars, Red giant stars, Magnetic variable stars
The Behavior of HgMn Stars in the Far UV-Paper 22: HD 37752. The analysis of three spectra of the He-weak Hg star HD 37752 recorded by the SWP camera on board the International Ultraviolet Explorer does not reveal variations of the far-ultraviolet flux of this star over one set of observations on 1982 September 19th. The IUE spectra cover only a very small fraction (10%) of the rotational period derived from the TESS lightcurve which precludes any conclusion on the far-ultraviolet variability of HD 37752.

Keywords: Helium-weak stars, Chemically peculiar stars
Redshift Survey of 12 Moderate-redshift Clusters. We conducted a redshift survey of 12 X-ray selected clusters in the redshift range z = 0.35-0.50 with MMT/Hectospec. The redshift surveys confirm that these clusters are massive systems. There are no massive groups or clusters projected along the line of sight that might contaminate the observed cluster X-ray properties significantly. We identify 25-79 members per cluster and refine the estimates of each cluster's mean redshift. We include the 8004 new redshifts in Data Behind the Figure.

Keywords: Galaxy clusters, Redshift surveys
FN8-23-7179: A Low-temperature Circumstellar Shell?. In the course of a narrow-band imaging survey for dwarf emission-line galaxies in a nearby void, we serendipitously discovered a low-excitation nebula that fits the profile of a shell surrounding a low-temperature star. The star has a parallax of 0.47 ± 0.34 mas with a most likely distance of 1686 pc. It has apparent magnitudes in $r^{\prime} $ and g of 18.5 and 19.54, absolute magnitudes ${M}_{r^{\prime} }$ and M  g  of 7.4 and 8.41, and a redshift of 140 km-1. The color and magnitude are consistent with a K6V dwarf. A lack of forbidden emission suggests that the nebular electron temperature is &lt; 3500° K.

Keywords: Stellar spectral lines, Circumstellar shells, Emission line stars
Measures of Variance on Windowed Gaussian Processes. The variance and fractional variance on a fixed time window (variously known as "rms percent" or "modulation index") are commonly used to characterize the variability of astronomical sources. We summarize properties of this statistic for a Gaussian process.

Keywords: Light curves, Time domain astronomy, Time series analysis
Radio-loud Exoplanet-exomoon Survey: GMRT Search for Electron Cyclotron Maser Emission. We conducted the first dedicated search for signatures of exoplanet-exomoon interactions using the Giant Metrewave Radio Telescope (GMRT) as part of the radio-loud exoplanet-exomoon survey. Due to stellar tidal heating, irradiation, and subsequent atmospheric escape, candidate "exo-Io" systems are expected to emit up to 106 times more plasma flux than the Jupiter-Io DC circuit. This can induce detectable radio emission from the exoplanet-exomoon system. We analyze three "exo-Io" candidate stars: WASP-49, HAT-P 12, and HD 189733. We perform 12 hr phase-curve observations of WASP-49b at 400 MHz during primary &amp; secondary transit, as well as first &amp; third quadratures achieving a 3σ upper limit of 0.18 mJy beam-1 averaged over four days. HAT-P 12 was observed with GMRT at 150 and 325 MHz. We further analyzed the archival data of HD 189733 at 325 MHz. No emission was detected from the three systems. However, we place strong upper limits on radio flux density. Given that most exo-Io candidates orbit hot Saturns, we encourage more multiwavelength searches (in particular low frequencies) to span the lower range of exoplanet B-field strengths constrained here.

Keywords: Radio continuum emission, Star-planet interactions, Natural satellites (Extrasolar), Exoplanets
Characterization of Population III Stars with Stellar Atmosphere and Evolutionary Modeling and Predictions of their Observability with the JWST. Population III stars were the first stars to form after the Big Bang and are believed to have made the earliest contribution to the metal content of the universe beyond the products of the Big Bang nucleosynthesis. These stars are theorized to have had extremely short life spans and therefore would only be observable at high redshifts (z ≥ 3-17) and faint apparent magnitudes (m AB ≳ 40). The direct detection of Population III stars therefore remains elusive. However, the recently launched James Webb Space Telescope (JWST) may be capable of detecting stars in the relevant magnitude range in the event of favorable gravitational lensing. Theoretical models are required to interpret these future observations. In this study, new evolutionary models and nonequilibrium model atmospheres were used to characterize the observable properties of zero-age main-sequence Population III stars. The calculated models cover a wide range of possible Population III stellar masses, from the minimum mass predicted by star formation studies to the maximum mass capable of maintaining hydrostatic equilibrium. Synthetic photometry and theoretical color-magnitude diagrams were calculated for the bands of the Near-Infrared Camera (NIRCam) on the JWST. The final results are compared to the scales of known lensing events and JWST magnitude limits. The purpose of this study is to calculate the observable parameters of Population III stars in the most optimal JWST bands in order to provide a theoretical foundation for anticipated future observations of this stellar population.

Keywords: Theoretical models, Population III stars, Carbon-nitrogen cycle, Proton-proton reaction, Gravitational lensing, Limiting magnitude
Spectroscopic Confirmation of a Population of Isolated, Intermediate-mass Young Stellar Objects. Wide-field searches for young stellar objects (YSOs) can place useful constraints on the prevalence of clustered versus distributed star formation. The Spitzer/IRAC Candidate YSO (SPICY) catalog is one of the largest compilations of such objects (~120,000 candidates in the Galactic midplane). Many SPICY candidates are spatially clustered, but, perhaps surprisingly, approximately half the candidates appear spatially distributed. To better characterize this unexpected population and confirm its nature, we obtained Palomar/DBSP spectroscopy for 26 of the optically bright (G &lt; 15 mag) "isolated" YSO candidates. We confirm the YSO classifications of all 26 sources based on their positions on the Hertzsprung-Russell diagram, H and Ca II line emission from over half the sample, and robust detection of infrared excesses. This implies a contamination rate of &lt;10% for SPICY stars that meet our optical selection criteria. Spectral types range from B4 to K3, with A-type stars being the most common. Spectral energy distributions, diffuse interstellar bands, and Galactic extinction maps indicate moderate-to-high extinction. Stellar masses range from ~1 to 7 M ☉, and the estimated accretion rates, ranging from 3 × 10-8 to 3 × 10-7 M ☉ yr-1, are typical for YSOs in this mass range. The 3D spatial distribution of these stars, based on Gaia astrometry, reveals that the "isolated" YSOs are not evenly distributed in the Solar neighborhood but are concentrated in kiloparsec-scale dusty Galactic structures that also contain the majority of the SPICY YSO clusters. Thus, the processes that produce large Galactic star-forming structures may yield nearly as many distributed as clustered YSOs.

Keywords: Herbig Ae/Be stars, T Tauri stars, Young stellar objects, Star formation, Spectroscopy
Retrieving C and O Abundance of HR 8799 c by Combining High- and Low-resolution Data. The formation and evolution pathway for the directly imaged multiplanetary system HR 8799 remains mysterious. Accurate constraints on the chemical composition of the planetary atmosphere(s) are key to solving the mystery. We perform a detailed atmospheric retrieval on HR 8799 c to infer the chemical abundances and abundance ratios using a combination of photometric data along with low- and high-resolution spectroscopic data (R ~ 20-35,000). We specifically retrieve [C/H], [O/H], and C/O and find them to be ${0.55}_{-0.39}^{+0.36}$ , ${0.47}_{-0.32}^{+0.31}$ , and ${0.67}_{-0.15}^{+0.12}$ at 68% confidence. The superstellar C and O abundances, yet a stellar C/O ratio, reveal a potential formation pathway for HR 8799 c. Planet c, and likely the other gas giant planets in the system, formed early on (likely within ~1 Myr), followed by further atmospheric enrichment in C and O through the accretion of solids beyond the CO ice line. The enrichment either preceded or took place during the early phase of the inward migration to the current planet locations.

Keywords: Exoplanet atmospheres
A Six Year, Low-resolution, Multibroadband Transit Photometry Study of HD 189733b. Transmission spectroscopy offers an invaluable opportunity to characterize the atmospheres of exoplanets. We present new ground-based optical transmission spectra of the hot Jupiter HD 189733b, derived from nine transits observed over a six year time span (2016-2021) using near-simultaneous $u^{\prime} g^{\prime} r^{\prime} i^{\prime} $ broadband observations. We achieve an average (best) precision of 435 (280) ppm by implementing an optical diffuser on the prime focus spectrograph from the 2.3 m Wyoming Infrared Observatory telescope. The data provide new measurements of the apparent planetary radius with respect to the stellar radius, the spectral index of atmospheric opacity, and the time variability of the two quantities. Our results indicate an enhanced spectral slope in the optical regime ≈2.4 times steeper than would be expected from canonical Rayleigh scattering and that is consistent with earlier measurements of a super-Rayleigh slope (SRS). While the effect of stellar activity on the transmission spectrum complicates the measurement of the spectral slope, our multiepoch data set over six years can measure and average over stellar variations, yielding a mean spectral index of -9.9 ± 4.4. The 1200 K equilibrium temperature of HD 189733b places it in a sweet spot for the formation of SRSs and is consistent with vigorously mixing hazes in the atmosphere. Additionally, we find variations in the depth of the lightcurve during two of the transits, explainable as an increase in occulted star spots during June 2021. Although the star is active, the mean level of stellar activity does not seem to vary dramatically over our six years of observations, leading us to conclude that the variability in stellar activity is modest at most.

Keywords: Exoplanet detection methods, Transit photometry, Exoplanet atmospheres
Evolved Eclipsing Binaries and the Age of the Open Cluster NGC 752. We present analyses of improved photometric and spectroscopic observations for two detached eclipsing binaries at the turnoff of the open cluster NGC 752: the 1.01 days binary DS And and the 15.53 days BD +37 410. For DS And, we find M 1 = 1.692 ± 0.004 ± 0.010M ⊙, R 1 = 2.185 ± 0.004 ± 0.008R ⊙, M 2 = 1.184 ± 0.001 ± 0.003M ⊙, and R 2 = 1.200 ± 0.003 ± 0.005R ⊙. We either confirm or newly identify unusual characteristics of both stars in the binary: the primary star is found to be slightly hotter than the main-sequence turnoff and there is a more substantial discrepancy in its luminosity compared to models (model luminosities are too large by about 40%), while the secondary star is oversized and cooler compared to other main-sequence stars in the same cluster. The evidence points to nonstandard evolution for both stars, but most plausible paths cannot explain the low luminosity of the primary star. BD +37 410 only has one eclipse per cycle, but extensive spectroscopic observations and the Transiting Exoplanet Survey Satellite light curve constrain the stellar masses well: M 1 = 1.717 ± 0.011M ⊙ and M 2 = 1.175 ± 0.005M ⊙. The radius of the main-sequence primary star near 2.9R ⊙ definitively requires large convective core overshooting (&gt;0.2 pressure scale heights) in models for its mass, and multiple lines of evidence point toward an age of 1.61 ± 0.03 ± 0.05 Gyr (statistical and systematic uncertainties). Because NGC 752 is currently undergoing the transition from nondegenerate to degenerate He ignition of its red clump stars, BD +37 410 A directly constrains the star mass where this transition occurs. * Based on observations made with with the Hobby-Eberly Telescope, which is a joint project of the University of Texas at Austin, the Pennsylvania State University, Stanford University, Ludwig-Maximilians-Universität München, and Georg-August-Universität Göttingen.

Keywords: Stellar ages, Spectroscopic binary stars, Stellar physics, Low mass stars, Eclipsing binary stars, Open star clusters