Sazuna/UAT_keywords huggingface dataset:
Accuracy of Stellar Mass-to-light Ratios of Nearby Galaxies in the Near Infrared. Future satellite missions are expected to perform all-sky surveys, thus providing the entire sky near-infrared spectral data and consequently opening a new window to investigate the evolution of galaxies. Specifically, the infrared spectral data facilitate the precise estimation of stellar masses of numerous low-redshift galaxies. We utilize the synthetic spectral energy distribution (SED) of 2853 nearby galaxies drawn from the DustPedia (435) and Stripe 82 regions (2418). The stellar mass-to-light ratio (M*/L) estimation accuracy over a wavelength range of 0.75‑5.0 μm is computed through the SED fitting of the multiwavelength photometric data set, which has not yet been intensively explored in previous studies. We find that the scatter in M*/L is significantly larger in the shorter and longer wavelength regimes due to the effect of the young stellar population and the dust contribution, respectively. While the scatter in M*/L approaches its minimum (∼0.10 dex) at ∼1.6 μm, it remains sensitive to the adopted star formation history model. Furthermore, M*/L demonstrates weak and strong correlations with the stellar mass and the specific star formation rate (SFR), respectively. Upon adequately correcting the dependence of M*/L on the specific SFR, the scatter in the M*/L further reduces to 0.02 dex at ∼1.6 μm. This indicates that the stellar mass can be estimated with an accuracy of ∼0.02 dex with a prior knowledge of SFR, which can be estimated using the infrared spectra obtained with future survey missions.

Keywords: Galaxies
Small and Close-in Planets are Uncommon Around A-type Stars. The Kepler and K2 missions enabled robust calculations of planet occurrence rates around FGKM-type stars. However, these missions observed too few stars with earlier spectral types to tightly constrain the occurrence rates of planets orbiting hotter stars. Using TESS, we calculate the occurrence rate of small (1 R⊕ &lt; Rp &lt; 8 R⊕), close-in (Porb &lt; 10 days) planets orbiting A-type stars for the first time. We search a sample of 20,257 bright (6 &lt; T &lt; 10) A-type stars for transiting planets using a custom pipeline and vet the detected signals, finding no reliable small planets. We characterize the pipeline completeness using injection─recovery tests and determine the 3σ upper limits of the occurrence rates of close-in sub-Saturns (4 R⊕ &lt; Rp &lt; 8 R⊕), sub-Neptunes (2 R⊕ &lt; Rp &lt; 4 R⊕), and super-Earths (1 R⊕ &lt; Rp &lt; 2 R⊕). We find upper limits of 2.2 ± 0.4 sub-Saturns and 9.1 ± 1.8 sub-Neptunes per 1000 A-type stars, which may be more than 3× and 6× lower than Kepler-era estimates for Sun-like stars. We calculate an upper limit of 186 ± 34 super-Earths per 1000 A-type stars, which may be more than 1.5× lower than that for M dwarfs. Our results hint that small, close-in planets become rarer around early-type stars and that their occurrence rates decrease faster than that of hot Jupiters with increasing host star temperature. We discuss plausible explanations for these trends, including star─disk interactions and enhanced photoevaporation of planet atmospheres.

Keywords: Extrasolar rocky planets, Transits, Exoplanets, Exoplanet astronomy, Exoplanet evolution, Transit photometry, Extrasolar gaseous planets, Exoplanet detection methods, Exoplanet formation
Old Dogs, New Tricks: Re-examining Photographic Spectra of Plaskett's Star. Photographic spectra of Plaskett's Star (HR 2420, HD 47129, V640 Monocerotis) that were recorded at the Dominion Astrophysical Observatory have been digitized with a flatbed scanner. Many of the spectra were recorded during campaigns in 1922 and 1937, and cover wavelengths between 0.39 and 0.50 μm. Spectra of poor quality are identified. Mean spectra near orbital phases 0.25 and 0.75 match many characteristics of synthetic spectra, although Hγ and He I λ4388 are exceptions. Evidence is presented that Hγ was affected by transient activity in 1937, but not in 1922. Emission lines of N III and He II move with wavelength in a manner that is consistent with them tracking the motion of the secondary, indicating that an "f" spectral type designation should be assigned to the secondary. The location of the peak that is associated with the secondary in cross-correlation functions changes with time near phase 0.75, although the mean amplitude of the radial velocity curve of the secondary did not change between the two campaigns. There is also an offset in velocities of the primary measured from Hγ and He I λ4472 near phase 0.25. The velocity curves of the components suggest a mass ratio that is larger than previous estimates, although uncertainties associated with the spectroscopic features attributed to the secondary, coupled with the wavelength resolution of the spectra, complicate efforts to determine robust masses. We conclude that the peculiarities in the radial velocity curves of the components have thus been in place for over a thousand orbital cycles.

Keywords: Spectroscopic binary stars, O stars
Two Earth-size Planets and an Earth-size Candidate Transiting the nearby Star HD 101581. We report the validation of multiple planets transiting the nearby (d = 12.8 pc) K5V dwarf HD 101581 (GJ 435, TOI─6276, TIC 397362481). This system consists of at least two Earth-size planets whose orbits are near a mutual 4:3 mean-motion resonance, HD 101581 b ( , P = 4.47 days) and HD 101581c ( , P = 6.21 days). Both planets were discovered in Sectors 63 and 64 TESS observations and statistically validated with supporting ground-based follow-up. We also identify a signal that probably originates from a third transiting planet, TOI-6276.03 ( , P = 7.87 days). These planets are remarkably uniform in size and their orbits are evenly spaced, representing a prime example of the "peas-in-a-pod" architecture seen in other compact multiplanet systems. At V = 7.77, HD 101581 is the brightest star known to host multiple transiting planets smaller than 1.5 R ⊕. HD 101581 is a promising system for atmospheric characterization and comparative planetology of small planets. *This paper includes data gathered with the 6.5 meter Magellan Telescopes located at Las Campanas Observatory, Chile.

Keywords: Exoplanet dynamics, Transit photometry, Exoplanet systems, Exoplanets
Resolving the Young 2 Cygni Runaway Star into a Binary Using iLocater. Precision radial velocity spectrographs that use adaptive optics (AO) show promise to advance telescope observing capabilities beyond those of seeing-limited designs. We are building a spectrograph for the Large Binocular Telescope (LBT) named iLocater that uses AO to inject starlight directly into single mode fibers. iLocater's first acquisition camera system (the SX camera), which receives light from one of the 8.4 m diameter primary mirrors of the LBT, was initially installed in summer 2019 and has since been used for several commissioning runs. We present results from first-light observations that include on-sky measurements as part of commissioning activities. Imaging measurements of the bright B3IV star 2 Cygni (V = 4.98) resulted in the direct detection of a candidate companion star at an angular separation of only θ = 70 mas. Follow-up AO measurements using Keck/NIRC2 recover the candidate companion in multiple filters. An R ≈ 1500 miniature spectrograph recently installed at the LBT named Lili provides spatially resolved spectra of each binary component, indicating similar spectral types and strengthening the case for companionship. Studying the multiplicity of young runaway star systems like 2 Cygni (36.6 ± 0.5 Myr) can help to understand formation mechanisms for stars that exhibit anomalous velocities through the Galaxy. This on-sky demonstration illustrates the spatial resolution of the iLocater SX acquisition camera working in tandem with the LBT AO system; it further derisks a number of technical hurdles involved in combining AO with Doppler spectroscopy.

Keywords: Exoplanets
Characterizing Superflares in HR 1099 Using Temporal and Spectral Analysis of XMM-Newton Observations. In the present paper, we analyze three energetic X-ray flares from the active RS CVn binary HR 1099 using data obtained from XMM-Newton. The flare duration ranges from 2.8 to 4.1 hr, with e-folding rise and decay times in the range of 27–38 minutes and 1.3–2.4 hr, respectively, indicating rapid rise and slower decay phases. The flare frequency for HR 1099 is one flare per rotation period. Time-resolved spectroscopy reveals peak flare temperatures of 39.44, 35.96, and 32.48 MK, emission measures of 7 × 1053–8 × 1054 cm‑3, global abundances of 0.250, 0.299, and 0.362 Z⊙, and peak X-ray luminosities of 1031.21‑32.29 erg s‑1. The quiescent state is modeled with a three-temperature plasma maintained at 3.02, 6.96, and 12.53 MK. Elemental abundances during quiescent and flaring states exhibit the inverse-first ionization potential (i-FIP) effect. We have conducted a comparative analysis of coronal abundances with previous studies and found evidence supporting the i-FIP effect. The derived flare semi-loop lengths of 6–8.9 × 1010 cm were found to be comparable to the other flares detected on HR 1099; however, they are significantly larger than typical solar flare loops. The estimated flare energies, ranging from 1035.83‑37.03 erg, classify these flares as super-flares. The magnetic field strengths of the loops are found to be in the range of 350–450 G. We diagnose the physical conditions of the flaring corona in HR 1099 through the observations of superflares and provide inference on the plasma processes.

Keywords: Stellar x-ray flares, Stellar abundances, Stellar activity, Stellar coronal loops, RS Canum Venaticorum variable stars, X-ray stars
BARBIE. Bayesian Analysis for Remote Biosignature Identification on exoEarths. III. Introducing the KEN. We deploy a newly generated set of geometric albedo spectral grids to examine the detectability of methane (CH4) in the reflected-light spectrum of an Earth-like exoplanet at visible and near-infrared (NIR) wavelengths with a future exoplanet imaging mission. By quantifying the detectability as a function of signal-to-noise ratio (SNR) and molecular abundance, we can constrain the best methods of detection with the high-contrast space-based coronagraphy slated for the next-generation telescopes such as the Habitable Worlds Observatory. We used 25 bandpasses between 0.8 and 1.5 μm. The abundances range from a modern-Earth level to an Archean-Earth level, driven by abundances found in available literature. We constrain the optimal 20%, 30%, and 40% bandpasses based on the effective SNR of the data, and investigate the impact of spectral confusion between CH4 and H2O on the detectability of each one. We find that a modern-Earth level of CH4 is not detectable, while an Archean-Earth level of CH4 would be detectable at all SNRs and bandpass widths. Crucially, we find that CH4 detectability is inversely correlated with H2O abundance, with the required SNR increasing as H2O abundance increases, while H2O detectability depends on CH4 abundance and the selected observational wavelength, implying that any science requirements for the characterization of Earth-like planet atmospheres in the visible─NIR should consider the abundances of both species in tandem.

Keywords: Biosignatures, Astrobiology, Exoplanet atmospheres
DECaPS and SMA Discovery of a Highly Inclined Class I Young Stellar Object with an Outflow: IRAS 08235–4316. We present images of IRAS 08235–4316 with the Dark Energy Camera Plane Survey (DECaPS; spanning 0.398–1.034 μm, at ∼1″ resolution) and the Submillimeter Array (SMA; at 1.38 mm (217 GHz) and ∼1 9 × 1 2 resolution), a young stellar object (YSO) located in the Vela constellation near to the Puppis boundary, detected in a systematic search for new large/extended emission sources. The DECaPS data show an asymmetric bipolar morphology with a large angular extent of ∼7 1 separated by a dark lane, characteristic of highly inclined protoplanetary disks and less-evolved YSOs with outflows. The SMA data show an extended continuum structure along the optical dark lane with a smaller angular extent of ∼4 6. The detected 12CO J = 2–1 emission tentatively shows a velocity gradient along the position angle of the dark lane/millimeter continuum, which may trace rotating gas. Additional 12CO emission is present, which could trace infalling/outflowing gas and/or a nearby gas cloud. We estimate a distance to IRAS 08235–4316 of at least ∼191 pc. Supported by additional spectral energy distribution modelling, we infer IRAS 08235–4316 to be a newly discovered Class I YSO with an outflow, host to an embedded protoplanetary disk, with a large millimeter radius of ∼440 au and dust mass ≳ 11 M⊕.

Keywords: Young stellar objects, Protoplanetary disks
The SDSS-V Local Volume Mapper: Data Analysis Pipeline. We introduce the data analysis pipeline (DAP) for the Sloan Digital Sky Survey V Local Volume Mapper (LVM) project, referred to as the LVM-DAP. We outline our methods for recovering both stellar and emission-line components from optical integral field spectroscopy, highlighting the developments and changes implemented to address specific challenges of the data set. The observations from the LVM project are unique because they cover a wide range of physical resolutions, from approximately 0.05 pc to 100 pc, depending on the distance to the target. This, along with the varying number of stars sampled in each aperture (ranging from zero, just one to a few, to thousands), presents challenges in using previous spectral synthesis methods and interpreting the spectral fits. We provide a detailed explanation of how we model the stellar content and separate it from the ionized gas emission lines. To assess the accuracy of our results, we compare them with both idealized and more realistic simulations, highlighting the limitations of our methods. We find that the DAP robustly corrects for stellar continuum features and recovers emission-line parameters (e.g., flux, equivalent width, systemic velocity, and velocity dispersion) with precision and accuracy that fulfill the requirements of the primary goal of the analysis. In addition, the recovered stellar parameters are reliable for single stars, while the recovery of integrated populations is less precise. We conclude with a description of the data products we provide, instructions for downloading and using our software, and a showcase illustrating the quality of the data and the analysis on a deep exposure taken on the Huygens region at the center of the Orion Nebula.

Keywords: Interstellar medium, Galaxy spectroscopy, Stellar properties, Emission line galaxies
The TANDEM Project as a Pilot Case for Wide-field Telescope Arrays. We give here an account of the Telescope Array eNabling DEbris Monitoring (TANDEM) project, an innovative concept aimed at flanking, on a shared piggyback mount, the main G. D. Cassini 152 cm f/8 telescope at the INAF-OAS observing premises in Loiano, Italy. The system is especially intended for space situational awareness activities related to the study of asteroids and comets and on the astrodynamical characterization of circumterrestrial space debris and artificial satellites. TANDEM consists of a combination of four customized and independently steerable 35 cm f/3 Newtonian telescopes, each equipped with a Moravian C4-16000 camera, observing through the BVRcIc filters of the Johnson–Cousins system. The camera carries on board a GSense 4040 (4096 × 4096 pixels) monochrome CMOS detector with an electronic shutter and a 9 μm pixel size. A corrected field of view of 2° × 2° is offered by each telescope, though quite special pointing capabilities and observing modes are available for the telescope array, such as to cover up to 16 deg2 across sparse celestial fields, each up to 20° in separation. While especially conceived for observing activities in the framework of the European Consortium for Space Surveillance and Tracking, TANDEM may also find additional applications in a more direct astronomical context, as we briefly outline along this review.

Keywords: Sky surveys, Wide-field telescopes, Telescope properties, Focal ratio, Telescopes
Comet 289P/Blanpain: Near-perihelion Activity and the Phoenicids. We present NEOWISE observations of Jupiter family comet 289P/Blanpain, the parent body of the Phoenicid meteoroid stream. Near-infrared images at 3.4 μm (W1) and 4.6 μm (W2) were obtained near perihelion on two occasions: UT 2019 October 30 (inbound, heliocentric distance Rh = 1.20 au) and UT 2020 January 11–12 (outbound, Rh = 1.01 au). To assess faint activity, we establish constraints on dust production driven by the limited sublimating area of water ice, based on studies of the 1956 Phoenicids. The ejected dust masses are Md = 4100 ± 200 kg (inbound) and 1700 ± 200 kg (outbound), respectively. The dust production rates are Qdust = 0.01–0.02 kg s‑1, corresponding to a dust-to-gas production ratio of 2 ≤ fdg ≤ 6. The resulting fractional active area, fA = 3.8 ± 1.9 × 10‑5, is the smallest yet reported. The absence of 4.6 μm (W2) excess suggests that 289P/Blanpain contains negligible amounts of CO2 and CO. Time-resolved analysis of the weighted mean of the W1 and W2 magnitudes finds a distinctive peak amplitude in the light curve having a rotational period Prot = 8.8536 ± 0.3860 hr, however, further verification is needed. The perihelion-normalized nongravitational acceleration,  αNG'  = 3.1 × 10‑6, is approximately an order of magnitude smaller than the trend observed for well-studied comets, consistent with weak outgassing. Current dust production from 289P/Blanpain, regardless of plausible assumptions for the particle size and distribution, is an order of magnitude too small to produce the Phoenicid stream within its ~300 yr dynamical lifetime. This suggests another mass supply, probably in 1743–1819, from rapid rotational destruction of a subkilometer precursor body, resulting in fragments equaling the mass of an object with radius ~ 100 m.

Keywords: Near-Earth objects, Sky surveys, Small Solar System bodies, Asteroids, Meteor trails, Short period comets, Meteors, Meteor streams, Infrared telescopes, Space telescopes, Comets, Catalogs
A High-resolution Spectroscopic Survey of Directly Imaged Companion Hosts. I. Determination of Diagnostic Stellar Abundances for Planet Formation and Composition. We present the first results of an extensive spectroscopic survey of directly imaged planet host stars. The goal of the survey is the measurement of stellar properties and abundances of 15 elements (including C, O, and S) in these stars. In this work, we present the analysis procedure and the results for an initial set of five host stars, including some very well-known systems. We obtain C/O ratios using a combination of spectral modeling and equivalent-width measurements for all five stars. Our analysis indicates solar C/O ratios for HR 8799 (0.59 ± 0.11), 51 Eri (0.54 ± 0.14), HD 984 (0.63 ± 0.14), and GJ 504 (0.54 ± 0.14). However, we find a supersolar C/O (0.81 ± 0.14) for HD 206893 through spectral modeling. The ratios obtained using the equivalent-width method agree with those obtained using spectral modeling but have higher uncertainties (∼0.3 dex). We also calculate the C/S and O/S ratios, which will help us to better constrain planet formation, especially once planetary sulfur abundances are measured using JWST. Finally, we find no evidence of highly elevated metallicities or abundances for any of our targets, suggesting that a super metal-rich environment is not a prerequisite for large, widely separated gas planet formation. The measurement of elemental abundances beyond carbon and oxygen also provides access to additional abundance ratios, such as Mg/Si, which could aid in further modeling of their giant companions.

Keywords: High resolution spectroscopy, Stellar abundances, Direct imaging, Atmospheric composition, Exoplanet formation
G321.93-0.01: A Rare Site of Multiple Hub-filament Systems with Evidence of Collision and Merging of Filaments. Hub-filament systems (HFSs) are potential sites of massive star formation (MSF). To understand the role of filaments in MSF and the origin of HFSs, we conducted a multiscale and multiwavelength observational investigation of the molecular cloud G321.93─0.01. The 13CO(J = 2─1) data reveal multiple HFSs, namely, HFS-1, HFS-2, and a candidate HFS (C-HFS). HFS-1 and HFS-2 exhibit significant mass accretion rates (  &gt; 10−3M⊙ yr−1) to their hubs (i.e., Hub-1 and Hub-2, respectively). Hub-1 is comparatively massive, having higher   than Hub-2, allowing to derive a relationship  , with β ~ 1.28. Detection of three compact H II regions within Hub-1 using MeerKAT 1.28 GHz radio continuum data and the presence of a clump (ATL-3), which meets Kauffmann and Pillai's criteria for MSF, confirm the massive star-forming activity in HFS-1. We find several low-mass Atacama Large Millimeter/submillimeter Array cores (1─9 M⊙) inside ATL-3. The presence of a compact H II region at the hub of C-HFS confirms that it is active in MSF. Therefore, HFS-1 and C-HFS are in relatively evolved stages of MSF, where massive stars have begun ionizing their surroundings. Conversely, despite a high  , the nondetection of radio continuum emission toward Hub-2 suggests it is in the relatively early stages of MSF. Analysis of 13CO(J = 2─1) data reveals that the formation of HFS-1 was likely triggered by the collision of a filamentary cloud about 1 Myr ago. In contrast, the relative velocities (≳1 km s−1) among the filaments of HFS-2 and C-HFS indicate their formation through the merging of filaments.

Keywords: Interstellar dust, Interstellar filaments, Massive stars, Star forming regions, Interstellar clouds
JWST-TST DREAMS: A Supersolar Metallicity in WASP-17 b's Dayside Atmosphere from NIRISS SOSS Eclipse Spectroscopy. We present the first emission spectrum of the hot Jupiter WASP-17 b using one eclipse observation from the JWST Near Infrared Imager and Slitless Spectrograph (NIRISS) Single Object Slitless Spectroscopy (SOSS) mode. Covering a wavelength range of 0.6–2.8 μm, our retrieval analysis reveals a strong detection of H2O in WASP-17 b's dayside atmosphere (6.4σ). Our retrievals consistently favor a supersolar dayside H2O abundance and a noninverted temperature–pressure profile over a large pressure range. Additionally, our examination of the brightness temperature reveals excess emission below 1 μm, suggesting the possibility of a high internal temperature (600–700 K) and/or contributions from reflected light. We highlight that JWST emission spectroscopy retrieval results can be sensitive to whether negative eclipse depths are allowed at optical wavelengths during light-curve fitting. Our findings deepen our understanding of WASP-17 b's atmospheric composition while also highlighting the sensitivity of our results to pressure–temperature profile parameterizations. This work is part of a series of studies by our JWST Telescope Scientist Team (TST), in which we will use Guaranteed Time Observations to perform Deep Reconnaissance of Exoplanet Atmospheres through Multi-instrument Spectroscopy (DREAMS).

Keywords: Exoplanet atmospheric composition , Hot Jupiters, Exoplanet atmospheres, Transmission spectroscopy, Astronomy data reduction
Adding RR Lyrae y-Band Template Light Curves to gatspy. We complement the y-band template light curves for RR Lyrae to the well-established template light curves in the ugriz-band, where the latter have been adopted in the astroML/gatspy python package as one of the period-search methods for RR Lyrae. These y-band template light curves were constructed based on the z-band time series data taken from the Sloan Digital Sky Survey (SDSS), the y-band light curves from the Pan-STARRS1 survey, and dedicated y-band observations using the Lulin One-meter Telescope for RR Lyrae located in the SDSS Stripe 82 region. These y-band template light curves, 9 for the ab-type RR Lyrae and 3 for the c-type RR Lyrae, can be applied in conjunction to the ugriz-band template light curves for upcoming sky surveys involving the y-band, such as the Vera C. Rubin Observatory Legacy Survey of Space and Time.

Keywords: Light curves, RR Lyrae variable stars