Sazuna/UAT_keywords huggingface dataset:
Dealing with Large Gaps in Asteroseismic Time Series. With long data sets available for asteroseismology from space missions, it is sometimes necessary to deal with time series that have large gaps. This is becoming particularly relevant for TESS, which is revisiting many fields on the sky every two years. Because solar-like oscillators have finite mode lifetimes, it has become tempting to close large gaps by shifting time stamps. Using actual data from the Kepler Mission, we show that this results in artificial structures in the power spectrum that compromise the measurements of mode frequencies and linewidths.

Keywords: Asteroseismology
The Behavior of HgMn Stars in the Far-UV-Paper 15: HD 216494. The analysis of high resolution spectra of the HgMn star HD 216494 recorded by the SWP camera on board the International Ultraviolet Explorer reveals no variations of the far-ultraviolet flux of this star over 2 days in 1995 July. The far-ultraviolet resonance lines of Si II are strong absorbers in the spectrum of HD 216494. The resonance lines of Ga II, Ga III and Hg II, characteristic of classical HgMn stars, are also present in the mean SWP spectrum of HD 216494. The currently available TESS lightcurves of HD 216494 has a double wave structure with a period between two successive deep minima equal to 3.486 ± 0.054 days which could be the rotation period.

Keywords: Mercury-manganese stars, Chemically peculiar stars
Stars on the Verge: From Days to Decades, Studying the Photometric Variations of the Red Supergiant W Persei. W Persei is a massive, luminous and large red supergiant located relatively nearby. W Persei is a probable SN-II progenitor. We analyzed ~120 yr of photometry from the AAVSO database. The analysis was conducted in the period analysis software Peranso where the CLEANest power spectrum and WWZ-wavelet programs were utilized. Two dominant periods of P = 532 ± 68 days and P = 2922 ± 140 days are found. Intermediate and transitory periods are also uncovered along with period events such as a significant increase in the long-period, period-merging and period-splitting. Using Transiting Exoplanet Survey Satellite observations, stochastic ~0.3-0.8 mmag light variability on timescales of ~0.3 day appears present. The physical causes of these variations is discussed.

Keywords: Red supergiant stars
On the Measurement of Vorticity in Astrophysical Fluids. Vorticity is central to the nature of, and dynamical processes in turbulence, including turbulence in astrophysical fluids. The results of Raymond et al. on vorticity in the post-shock fluid of the Cygnus Loop supernova remnant are therefore of great interest. I consider the degree to which spectroscopic measurements of an optically thin line, the most common type of astronomical velocimetry, can yield unambiguous measurements of the vorticity in a fluid. I consider an ideal case of observations in the plane of a flow which possesses vorticity in a direction perpendicular to the plane of observations. The observationally deduced vorticity (referred to as the pseudovorticity) is a reasonable match for the true vorticity. However, the pseudovorticity of an irrotational model flow is also nonzero, and comparable in magnitude to that for a vortical flow. Astronomical spectroscopic observations may yield a good estimate of the vorticity, but its robustness cannot be insured.

Keywords: Interplanetary turbulence, Plasma astrophysics, Interstellar medium
How Bar Fraction Depends on Baryon Fraction. We use Galaxy Zoo 2 morphologies (based on SDSS Legacy Imaging) alongside the completed Arecibo Legacy Fast ALFA survey measuring H I to investigate the correlation between bar fraction and an estimate of baryonic mass fraction for a sample of nearby (z &lt; 0.06) disk galaxies (M ⋆ &gt; 109 M ⊙). As expected from theoretical considerations, and as seen in previous work using different samples/morphological classifications, we find clear evidence of an increase in bar fraction, particularly strong bar fraction in galaxies with larger baryonic mass fractions (i.e., heavier discs for their dark matter halo).

Keywords: Barred spiral galaxies
Release of TESS Objects of Interest from TESS-SPOC Sectors 48 to 50 Full Frame Images. We report 20 new potential transiting exoplanet candidates detected in 10 minutes full frame images from the first TESS Extended Mission. We searched the light curves produced by the TESS Science Processing Operations Center pipeline from Sectors 48 through 50 and uncovered 9257 Threshold Crossing Events. We used the program TESS-ExoClass, modeling, and catalog comparison to vet the detections and compile a list of 20 promising objects of interest. These exoplanet candidates will be submitted to the Exoplanet Follow-up Observing Program as Community TESS Objects of Interest. The target pixels, light curves, and data validation reports are available on the Mikulski Archive for Space Telescopes.

Keywords: Exoplanet astronomy, Exoplanet catalogs, Transits, Exoplanets
New Surface Abundances for HD 216494 (74 Aqr). New abundances are derived for the brightest member of 74 Aqr. The profile of the Mg II line at 4481 Å is composite and clearly shows three components which confirms the classification of 74 Aqr as a triple SB3 system. The derived abundance pattern confirms the HgMn nature of this star. Helium and magnesium are found to be more deficient than in previous studies while phosphorus is less overabundant.

Keywords: Chemically peculiar stars
HIPPI-2 Commissioned at MIRA. We have commissioned the High Precision Polarimetric Instrument 2 on the Monterey Institute for Research in Astronomy's 36 inch telescope at its Bernard M. Oliver Observing Station. The night-to-night precision on bright stars is measured as σ  p  = 7.1 ppm and e  p  = 1.7 ppm in $g^{\prime} ;$ its accuracy on high polarization standard stars is 1.2%, despite the instrument not being actively guided. This matches the best performance achieved on much larger telescopes, which we attribute to the excellent site conditions.

Keywords: Polarimeters, Polarimetry, Astronomical instrumentation
Evolutionary Status of Selected Post-AGB Stars Based on Gaia DR3. The evolutionary status of 24 post-AGB stars is presented based on Gaia DR3 data. All 24 stars have parallaxes accurate to better than 3σ and have RUWE values &lt;1.4. Based on the Gaia DR3 distances the absolute luminosities are derived. For 14 of the stars, the luminosities confirm their post-AGB evolutionary stage. However, V1027 Cyg, which was previously classified as a post-AGB star, is found to have a higher luminosity than would be expected if it was truly a post-AGB star; thus it may be an evolved, massive, pulsating semi-regular variable star of type G7Ia. For 9 of the stars, the luminosities are lower than 1000 L ⊙, indicating that some are post-HB stars and some are post-RGB stars.

Keywords: Post-asymptotic giant branch stars
Updated Orbit and Observations of Spectroscopic Binary HD 2019. Binary star system HD 2019 was studied by the David Dunlap Observatory between 1935 and 1947. From the spectroscopic data obtained, the orbital elements of the system were defined. Between then and now, there have been no updated studies of this binary star system. We set out to update the orbit of HD 2019 with new spectroscopic data obtained at Clarkson University's Reynolds Observatory. After finding the radial velocities of the star or stars visible in each spectrum, estimates of the error for each measurement were made. From the radial velocities and error estimates, new orbital elements were fit using the data from David Dunlap Observatory combined with the new data collected at Clarkson. These results lead to further investigation of the eccentricity of the orbit. Using the method of Lucy 2005, we ran a test to check the statistical significance of the eccentric orbit using p-value testing.

Keywords: Observational astronomy, Chemically peculiar giant stars, Binary stars, Mercury-manganese stars, Spectral line identification, Spectroscopic binary stars, Radial velocity, Chemically peculiar stars
Synthetic Color-Magnitude Diagrams for the Globular Cluster 47 Tucanae. Globular clusters contain the largest coeval populations of stars in the Milky Way, making them prime targets for stellar evolution studies. We present new theoretical isochrones for the brightest monometallic globular cluster 47 Tucanae, based on the spectroscopic measurements of the chemical composition in literature. Calculated colors are compared to existing photometric observations with Advanced Camera for Surveys on the Hubble Space Telescope. We find that the adopted abundances are consistent with the blue tail of the observed color distribution, implying a possible systematic offset between spectroscopic and photometric abundances of globular clusters. Additionally, we make color-magnitude predictions for future observations with the Near Infrared Camera on the James Webb Space Telescope in bands corresponding to the ongoing observational campaigns.

Keywords: Globular star clusters, Stellar evolutionary models, Chemical abundances, Stellar atmospheres
Prediction of an Earth-sized Planet Formed in the Habitable Zone of the SPECULOOS-2 System. Transiting planets in the nearby TRAPPIST-1 system provide rare examples of habitable zone (HZ), Earth-sized planets that can be characterized via transmission spectroscopy. However, these present-day HZ planets likely formed interior to HZ and probably underwent an evolution very different from that of Earth. We present the integrative analysis of the planetary architecture of the recently discovered planetary system SPECULOOS-2. Our analysis answers the question: If there are additional exoplanets in the SPECULOOS-2 system, what are their orbital and physical properties? We predict an Earth-sized planet in the habitable zone (P ~ 14.5-18.2 days). In contrast to TRAPPIST-1e, this predicted planet most likely completed its formation inside the habitable zone. If confirmed, this planet will offer an Earth-sized, habitable zone planet that is likely to have an evolutionary path more similar to Earth than those in the TRAPPIST-1 system.

Keywords: Exoplanets, Astrostatistics
M31N 1926-07c: A Recurrent Nova in M31 with a 2.8 yr Recurrence Time. The M31 recurrent nova M31N 1926-07c has had five recorded eruptions. Well-sampled light curves of the two most recent outbursts, in 2020 January (M31N 2020-01b) and 2022 September (M31N 2022-09a), are presented showing that the photometric evolution of the two events were quite similar, with peak magnitudes of R = 17.2 ± 0.1 and R = 17.1 ± 0.1, and t 2 times of 9.7 ± 0.9 and 8.1 ± 0.5 days for the 2020 and 2022 eruptions, respectively. After considering the dates of the four most recent eruptions (where the cycle count is believed to be known), a mean recurrence interval of &lt;P rec&gt; = 2.78 ± 0.03 yr is found, establishing that M31N 1926-07c has one of the shortest recurrence times known.

Keywords: Novae, Time domain astronomy, Recurrent novae, Cataclysmic variable stars, Andromeda Galaxy
A Small Centaur with a Coma and Tail and Another with a Coma. We report discovery and initial investigation of extended optical emission from two known Centaurs, 2020 XV1 and 2021 RK133. These objects are classified as Centaurs using the Jet Propulsion Laboratory HORIZONS Centaur criteria, but not the Minor Planet Center criteria, as both have q &lt; 5.2 au. We derive limits on the fraction of light coming from the nuclei and from the extended emission regions and derive magnitude limits for the nuclei. Using these nuclear magnitudes and an assumed albedo of 7% we estimate that these two Centaurs are rather small, with diameters of no more than 2.4 and 1.7 km.

Keywords: Comets, Centaur group
The Effect of Binary Eccentricity on the Development of a Warp in a Protoplanetary Disk. Upon interaction with a non-spherically symmetric gravitational potential, such as that from a central misaligned binary, a protoplanetary disk experiences precessional torques leading to warps and even tears. Several low-viscosity simulations of misaligned protoplanetary discs were run with several values of binary eccentricity (e), along with a set of identical but aligned runs for comparison. In a wavelike protoplanetary disk the eccentricity was found to be a driving factor in the development of a warp, the amplitude of which increases with e.

Keywords: Binary stars, Protoplanetary disks, Eccentricity, Circumstellar disks
Assessment of the Roche and the Darwin-Radau Approximations for Rotating Astrophysical Objects. Assessment of two of the frequently used approximations for rotating astrophysical objects, the Roche and the Darwin-Radau approximations, is performed by comparing the rotational frequencies computed by these approximations with those of self-consistent numerical hydrostatic solutions. Overall, the Darwin-Radau approximation performs better, though the error increases as the rotational oblateness increases. It should be also remarked that the Darwin-Radau approximation does not provide a closed-form formula of the frequency as a function of the oblateness.

Keywords: Stellar rotation
Deriving Median Disk Lifetimes from Disk Lifetime Distributions. Observations show that individual protoplanetary disk lifetimes vary from &lt;1 Myr to ≫20 Myr. The disk lifetime distribution is currently unknown. For the example of a Gaussian distribution of the disk lifetime, I suggest a simple method for deducing such a disk lifetimes distribution. The median disk lifetimes inferred with this method is also shown.

Keywords: Planet formation
Testing a Galactic Lensing Hypothesis with the Prompt Emission of GRB 221009A. Even at modest amplification, the optical depth to gravitational lensing through the Galaxy is &lt; 10-5. However, the large apparent isotropic-equivalent energy of GRB 221009A coupled with a path through low Galactic latitude suggests that the conditional probability that this particular GRB was lensed is greater than the very low a priori expectation. With the extreme brightness of the prompt emission, this Galactic lensing hypothesis can be constrained by autocorrelation analysis of Fermi photons on 0.1-1000 ms timescales. In relating lensing mass, magnification, and autocorrelation timescale, I show that a lensed-induced autocorrelation signature by stellar lenses falls below the minimal variability timescale (MVT) expected from a black hole central engine. However, lensing by Galactic dark matter MACHOs (M  l  &gt; 10-1000 M ⊙) could be confirmed with this approach. Regardless, at a peak γ-ray photon rate of &gt; 30 ms-1, GRB 221009A represents a prime opportunity to measure the smallest MVTs of GRBs.

Keywords: Gravitational microlensing, Gamma-ray bursts, Dark matter
The Intermediate Polar FO Aquarii Has Not Been the Same Since Recovering from a Series of Low States. FO Aqr is a bright intermediate polar that has long displayed large amplitude photometric variations corresponding to the 20.9 minutes spin period of its white dwarf. Between 2016 and 2020, the system suffered a series of unprecedented low-states, but recent data shows that it has now recovered to its normal optical luminosity. We compare the light curves obtained by K2/Kepler in 2014 with photometry from the TESS mission obtained in 2021. We find that the spin pulse that had been the dominant feature of the light curve in 2014 is now weak over the second half of the binary orbit and that a beat pulse is enhanced in the TESS photometry. Variations at approximately twice the spin frequency are now seen over the second half of the orbit. These photometric properties may be the new normal for FO Aqr now that its white dwarf has begun to spin down.

Keywords: DQ Herculis stars, Cataclysmic variable stars, White dwarf stars, Magnetic variable stars
A Significant Sudden Ionospheric Disturbance Associated with Gamma-Ray Burst GRB 221009A. We report the detection of a significant sudden ionospheric disturbance in the D-region of Earth's ionosphere (~60-100 km), which was associated with the massive γ-ray burst GRB 221009A that occurred on 2022 October 9. We identified the disturbance over northern Europe-a result of the increased ionization by X- and γ-ray emission from the GRB-using very low frequency radio waves as a probe of the D-region. These observations demonstrate that an extra-galactic GRB (z ~ 0.151) can have a significant impact on the terrestrial atmosphere and illustrates that the Earth's ionosphere can be used as a giant X- and γ-ray detector. Indeed, these observations may provide an insight into the impacts of GRBs on the ionospheres of planets in our solar system and beyond.

Keywords: D layer, Gamma-ray bursts, Gamma-rays, Earth ionosphere
Signs of Emissions of Alkali Metals Na I, Li I, and K I During First Minutes After DART Probe Crash on Dimorphos. We present the results of the analysis of spectral observations taken a few minutes before, at the time, and in the first minutes after the impact of the DART probe on the asteroid Dimorphos. Our analysis showed signs of Na I, Li I, and K I alkali metal emissions appearing at the time of the impact and for several minutes after it.

Keywords: Near-Earth objects, Asteroids, Spectroscopy
The Behavior of HgMn Stars in the Far UV-Paper 17: HD 35548A. The analysis of high resolution spectra of the HgMn star HD 35548A recorded by the SWP camera on board the International Ultraviolet Explorer reveals no variations of the far-ultraviolet flux of this star over about 21 hr in 1981. The resonance lines of Ga II and Ga III, characteristic of classical HgMn stars, are salient features in the mean SWP spectrum of HD 35548A. The TESS lightcurve of the system HD 35548A and HD 35548B has an asymetric structure with a steep descent to the minimum and a slower rise to next maximum. The period, measured between two successive maxima, is close to 6.07 ± 0.09 days which could be the orbital and rotational period due to synchronization with the companion of HD 35548A.

Keywords: Mercury-manganese stars, Chemically peculiar stars
The Full Extent of the Tidal Tail in Arp 93. Arp 93 consists of two interacting galaxies, NGC 7284 and NGC 7284 and a long tidal tail. However, it has not been depicted in its fullest extent in previous images. I present a deep, new image that illustrates the tail's wide path, that is more than double the previously recorded angular distance from the interacting pair of galaxies.

Keywords: Tidal tails, Interacting galaxies
Refinement of the Parameters of the Negative Polarization Branch of Asteroid 419 Aurelia in the R Filter. Asteroid 419 Aurelia is of particular interest due to its unusual optical properties. But the lack of observational data, especially in the R filter, did not allow one to accurately determine the parameters of the negative polarization branch of this asteroid. We carried out the precise measurements of the Aurelia's degree of linear polarization at different phase angles. The data obtained made it possible to accurately approximate a complete branch of the negative polarization. Thanks to this, it was possible to obtain refined values of the parameters of the negative polarization branch.

Keywords: Polarimetry, Asteroids
Fitting Rotational Frequency of Polytropes as a Function of their Oblateness. Giving a simple functional relationship between the rotational frequency and the centrifugal deformation for compressible stellar models is useful both in observational and theoretical astrophysics. Here I present simple Padé approximants for the rotational frequency of polytropic stars (index N = 1, 1.5, 3) as a function of the oblateness, which are valid at the order of ${ \mathcal O }[{10}^{-2}]$ percent for the speed of rotation up to the mass-shedding limit.

Keywords: Stellar rotation
Gravitational Wave Acceleration to Relativistic Energies. A charged particle can be accelerated to arbitrarily high energies by maintaining a permanent resonance with the phase of a planar gravitational wave propagating along a uniform magnetic field. The Doppler-shifted cyclotron autoresonance could potentially result in electromagnetic afterglows near gravitational-wave sources.

Keywords: Gravitational wave sources
Discovery of a Mid-L Dwarf Companion to the L 262-74 System. We present the discovery of CWISE J151044.74-524923.5, a wide low-mass companion to the nearby (~24.7 pc) system L 262-74, which was identified through the Backyard Worlds: Planet 9 citizen science project. We detail the properties of the system, and we assess that this companion is a mid-L dwarf, which will need to be verified spectroscopically. With an angular separation of 74.″3, we estimate a projected physical separation of ~1837 au from the central system.

Keywords: Multiple stars, Brown dwarfs, Low mass stars, Proper motions
The Behavior of HgMn Stars in the Far UV-Paper 18: HD 209459. The analysis of 14 high resolution spectra of the Hg star HD 209459 recorded by the SWP camera on board the International Ultraviolet Explorer reveals large variations of the far ultraviolet flux of this star over the 18 yr of the mission. The two available Transiting Exoplanet Survey Satellite lightcurves of HD 209459 are periodic. The period, measured between two successive minima, is close to 6.25 ± 0.03 days which could be the rotational period of HD 209459. The FUV variations, which are unexpected for a late normal B-type star or a Hg-rich star, could be caused by large horizontal chemical or occasional thermal gradients.

Keywords: Mercury-manganese stars, Chemically peculiar stars
Light Curve Analysis of Nine Algol (EA) Eclipsing Binaries Discovered During the Dauban Survey. The Dauban Survey was a project focused on photometric observations in the Milky Way. This project was a collaboration between Francois Kugel and Jerome Caron utilizing the Observatoire de Chante-Perdix Dauban (MPC A77) in France between 2012 September 17 and 2014 July 20. Over this period, a total of 7826 known variable stars and 5521 new, unknown variable stars were detected. In particular, 497 new variables were published in the AAVSO VSX database. These included Mira Ceti, cataclysmic variables, RR Lyrae, cepheids, and nine EA eclipsing systems. It is the nine EA eclipsing binaries that are the focus of this research.

Keywords: Eclipsing binary stars
A Deep Dimming and Abrupt Recovery of a YSO Candidate in MonR2. We report on a nearly factor-of-ten fade and then re-brightening after several months of [CMD97]-1031, a candidate young stellar object. Through fitting of light curve data from ZTF and ATLAS, we find a dip amplitude &gt;2.5 mag and duration 80-320 days. After the large dip, the source recovered to slightly fainter brightness and redder color.

Keywords: Young stellar objects, Young star clusters, Variable stars, Star forming regions
Rotation Curve Decompositions with Gaussian Processes: Taking into Account Data Correlations Leads to Unbiased Results. Correlations between velocity measurements in disk galaxy rotation curves are usually neglected when fitting dynamical models. Here I show how data correlations can be taken into account in rotation curve decompositions using Gaussian Processes. I find that marginalizing over correlation parameters proves critical to obtain unbiased estimates of the luminous and dark matter distributions in galaxies.

Keywords: Galaxy dark matter halos, Galaxy rotation curves, Disk galaxies