Sazuna/UAT_keywords huggingface dataset:
Revealing the Vertical Cloud Structure of a Young Low-mass Brown Dwarf, an Analog to the β-Pictoris b Directly Imaged Exoplanet, through Keck I/MOSFIRE Spectrophotometric Variability. Young brown dwarfs are analogs to giant exoplanets, as they share effective temperatures, near-infrared colors, and surface gravities. Thus, the detailed characterization of young brown dwarfs might shed light on the study of giant exoplanets that we are currently unable to observe with a sufficient signal-to-noise to allow a precise characterization of their atmospheres. 2MASS J22081363+2921215 is a young L3 brown dwarf, and a member of the β-Pictoris young moving group (23 ± 3 Myr), which shares its effective temperature and mass with the β Pictoris b giant exoplanet. We performed a ~2.5 hr spectrophotometric J-band monitoring of 2MASS J22081363+2921215 with the MOSFIRE multi-object spectrograph, installed at the Keck I telescope. We measured a minimum variability amplitude of 3.22 ± 0.42% for its J-band light curve. The ratio between the maximum and the minimum flux spectra of 2MASS J22081363+2921215 shows a weak wavelength dependence, and a potentially enhanced variability amplitude in its alkali lines. Further analysis suggests that the variability amplitudes of the alkali lines are higher than its overall variability amplitude (4.5%-11%, depending on the lines). The variability amplitudes of these lines are lower if we degrade the resolution of the original MOSFIRE spectra to R ~ 100, which explains why this potentially enhanced variability of the alkali lines had not been found previously in Hubble Space Telescope (HST)/WFC3 light curves. Using radiative-transfer models, we obtained the different cloud layers that might be introducing the spectrophotometric variability we observe for 2MASS J22081363+2921215, which further supports the measured enhanced variability amplitudes of the alkali lines. We provide an artistic recreation of the vertical cloud structure of this β-Pictoris b analog.

Keywords: L dwarfs
OGLE-2019-BLG-0960 Lb: the Smallest Microlensing Planet. We report the analysis of OGLE-2019-BLG-0960, which contains the smallest mass-ratio microlensing planet found to date (q = 1.2-1.6 × 10-5 at 1σ). Although there is substantial uncertainty in the satellite parallax measured by Spitzer, the measurement of the annual parallax effect combined with the finite source effect allows us to determine the mass of the host star (ML = 0.3-0.6 M☉), the mass of its planet (mp = 1.4-3.1 M⊕), the projected separation between the host and planet (a⊥ = 1.2-2.3 au), and the distance to the lens system (DL = 0.6-1.2 kpc). The lens is plausibly the blend, which could be checked with adaptive optics observations. As the smallest planet clearly below the break in the mass-ratio function, it demonstrates that current experiments are powerful enough to robustly measure the slope of the mass-ratio function below that break. We find that the cross-section for detecting small planets is maximized for planets with separations just outside of the boundary for resonant caustics and that sensitivity to such planets can be maximized by intensively monitoring events whenever they are magnified by a factor A &gt; 5. Finally, an empirical investigation demonstrates that most planets showing a degeneracy between (s &gt; 1) and (s &lt; 1) solutions are not in the regime ( $| \mathrm{log}s| \gg 0$ ) for which the "close"/"wide" degeneracy was derived. This investigation suggests that there is a link between the "close"/"wide" and "inner/outer" degeneracies and also that the symmetry in the lens equation goes much deeper than symmetries uncovered for the limiting cases.

Keywords: Gravitational microlensing exoplanet detection
Constraining the Orbit and Mass of epsilon Eridani b with Radial Velocities, Hipparcos IAD-Gaia DR2 Astrometry, and Multiepoch Vortex Coronagraphy Upper Limits. ϵ Eridani is a young planetary system hosting a complex multibelt debris disk and a confirmed Jupiter-like planet orbiting at 3.48 au from its host star. Its age and architecture are thus reminiscent of the early Solar System. The most recent study of Mawet et al., which combined radial-velocity data and Ms-band direct imaging upper limits, started to constrain the planet's orbital parameters and mass, but are still affected by large error bars and degeneracies. Here we make use of the most recent data compilation from three different techniques to further refine ϵ Eridani b's properties: RVs, absolute astrometry measurements from the Hipparcos and Gaia missions, and new Keck/NIRC2 Ms-band vortex coronagraph images. We combine this data in a Bayesian framework. We find a new mass, ${M}_{b}={0.66}_{-0.09}^{+0.12}$ MJup, and inclination, $i=78.{81}_{-22.41\mathop{}\limits^{^\circ }}^{+29.34}$ , with at least a factor 2 of improvement over previous uncertainties. We also report updated constraints on the longitude of the ascending node, the argument of the periastron, and the time of periastron passage. With these updated parameters, we can better predict the position of the planet at any past and future epoch, which can greatly help define the strategy and planning of future observations and with subsequent data analysis. In particular, these results can assist the search for a direct detection with JWST and the Nancy Grace Roman Space Telescope's coronagraph instrument.

Keywords: Exoplanets, Exoplanet astronomy, Direct imaging, Astrometry, Radial velocity, Debris disks
SOLES I: The Spin-Orbit Alignment of K2-140 b. Obliquity measurements for stars hosting relatively long-period giant planets with weak star-planet tidal interactions may play a key role in distinguishing between formation theories for shorter-period hot Jupiters. Few such obliquity measurements have been made to date due to the relatively small sample of known wide-orbiting, transiting Jovian-mass planets and the challenging nature of these targets, which tend to have long transit durations and orbit faint stars. We report a measurement of the Rossiter-McLaughlin effect across the transit of K2-140 b, a Jupiter-mass planet with period P = 6.57 days orbiting a V = 12.6 star. We find that K2-140 is an aligned system with projected spin-orbit angle λ = 0.5° ± 9.7°, suggesting a dynamically cool formation history. This observation builds toward a population of tidally detached giant planet spin-orbit angles that will enable a direct comparison with the distribution of close-orbiting hot-Jupiter orbital configurations, elucidating the prevalent formation mechanisms of each group.

Keywords: Exoplanet dynamics, Planetary theory, Exoplanet detection methods, Exoplanets, Planetary alignment, Exoplanet systems, Exoplanet astronomy, Exoplanet evolution, Planetary system formation, Star-planet interactions, Exoplanet formation, Extrasolar gaseous giant planets
The Infrared Evolution of Dust in V838 Monocerotis. Luminous Red Variables are most likely eruptions that are the outcome of stellar mergers. V838 Mon is one of the best-studied members of this class, representing an archetype for stellar mergers resulting from B-type stars. As result of the merger event, "nova-like" eruptions occur driving mass loss from the system. As the gas cools considerable circumstellar dust is formed. V838 Mon erupted in 2002 and is undergoing very dynamic changes in its dust composition, geometry, and infrared luminosity providing a real-time laboratory to validate mineralogical condensation sequences in stellar mergers and evolutionary scenarios. We discuss recent NASA Stratospheric Observatory for Infrared Astronomy 5-38 μm observations combined with archival NASA Spitzer spectra that document the temporal evolution of the freshly formed (within the last ≲20 yr) circumstellar material in the environs of V838 Mon. Changes in the 10 μm spectral region are strong evidence that we are witnessing a classical dust condensation sequence expected to occur in oxygen-rich environments where alumina formation is followed by that of silicates at the temperature cools.

Keywords: Asymptotic giant branch stars, Circumstellar dust, Astrochemistry
Double-lined Spectroscopic Binaries in the APOGEE DR16 and DR17 Data. APOGEE spectra offer ≲1 km s−1 precision in the measurement of stellar radial velocities. This holds even when multiple stars are captured in the same spectrum, as happens most commonly with double-lined spectroscopic binaries (SB2s), although random line-of-sight alignments of unrelated stars can also occur. We develop a code that autonomously identifies SB2s and higher order multiples in the APOGEE spectra, resulting in 7273 candidate SB2s, 813 SB3s, and 19 SB4s. We estimate the mass ratios of binaries, and for a subset of these systems with a sufficient number of measurements we perform a complete orbital fit, confirming that most systems with periods of &lt;10 days have circularized. Overall, we find an SB2 fraction (F SB2) ∼ 3% among main-sequence dwarfs, and that there is not a significant trend in F SB2 with temperature of a star. We are also able to recover a higher F SB2 in sources with lower metallicity, however there are some observational biases. We also examine light curves from TESS to determine which of these spectroscopic binaries are also eclipsing. Such systems, particularly those that are also pre- and post-main sequence, are good candidates for a follow-up analysis to determine their masses and temperatures.

Keywords: Binary stars, Spectroscopic binary stars, Spectroscopy, Eclipsing binary stars, Orbit determination, Near infrared astronomy
UV Fluorescence Traces Gas and Lyα Evolution in Protoplanetary Disks. Ultraviolet spectra of protoplanetary disks trace distributions of warm gas at radii where rocky planets form. We combine Hubble Space Telescope Cosmic Origins Spectrograph observations of H2 and CO emission from 12 classical T Tauri stars to more extensively map inner disk surface layers, where gas temperature distributions allow radially stratified fluorescence from the two species. We calculate empirical emitting radii for each species under the assumption that the line widths are entirely set by Keplerian broadening, demonstrating that the CO fluorescence originates further from the stars $\left(r\sim 20\,\mathrm{au}\right)$ than the H2 $\left(r\sim 0.8\,\mathrm{au}\right)$ . This is supported by 2D radiative transfer models, which show that the peak and outer radii of the CO flux distributions generally extend further into the outer disk than the H2. These results also indicate that additional sources of Lyα photons remain unaccounted for, requiring more complex models to fully reproduce the molecular gas emission. As a first step, we confirm that the morphologies of the UV-CO bands and Lyα radiation fields are significantly correlated and discover that both trace the degree of dust disk evolution. The UV tracers appear to follow the same sequence of disk evolution as forbidden line emission from jets and winds, as the observed Lyα profiles transition between dominant red wing and dominant blue wing shapes when the high-velocity optical emission disappears. Our results suggest a scenario where UV radiation fields, disk winds and jets, and molecular gas evolve in harmony with the dust disks throughout their lifetimes.

Keywords: Hubble Space Telescope, Molecular spectroscopy, Protoplanetary disks, Pre-main sequence
orvara: An Efficient Code to Fit Orbits Using Radial Velocity, Absolute, and/or Relative Astrometry. We present an open-source Python package, Orbits from Radial Velocity, Absolute, and/or Relative Astrometry (orvara), to fit Keplerian orbits to any combination of radial velocity, relative astrometry, and absolute astrometry data from the Hipparcos-Gaia Catalog of Accelerations. By combining these three data types, one can measure precise masses and sometimes orbital parameters even when the observations cover a small fraction of an orbit. The computational performance of orvara is achieved with an eccentric anomaly solver 5-10 times faster than commonly used approaches and low-level memory management to avoid Python overheads and by analytically marginalizing out parallax, barycenter proper motion, and instrument-specific radial velocity zero-points. Through its integration with the Hipparcos and Gaia intermediate astrometry package htof, orvara can properly account for the epoch astrometry measurements of Hipparcos and the measurement times and scan angles of individual Gaia epochs. We configure orvara with modifiable .ini configuration files tailored to any specific stellar or planetary system. We demonstrate orvara with a case study application to a recently discovered white dwarf/main-sequence system, HD 159062. By adding absolute astrometry to literature radial velocity and relative astrometry data, our comprehensive Markov Chain Monte Carlo analysis improves the precision of HD 159062B's mass by more than an order of magnitude to {0.6083}_{-0.0073}^{+0.0083}$ M⊙. We also derive a low eccentricity and large semimajor axis, establishing HD 159062AB as a system that did not experience Roche lobe overflow.

Keywords: Astrometric exoplanet detection, Astronomy software, Radial velocity, Exoplanet astronomy, Keplerian orbit, Orbit determination
New Infrared Spectral Indices of Luminous Cold Stars: From Early K to M Types. We present infrared spectral indices (1.0-2.3 μm) of Galactic late-type giants and red supergiants (RSGs). We used existing and new spectra obtained at resolution power R = 2000 with SpeX on the IRTF telescope. While a large CO equivalent width (EW), at 2.29 μm ([CO, 2.29] ≳ 45 Å) is a typical signature of RSGs later than spectral type M0, $[\mathrm{CO}]$ of K-type RSGs and giants are similar. In the [CO, 2.29] versus [Mg I, 1.71] diagram, RSGs of all spectral types can be distinguished from red giants because the Mg I line weakens with increasing temperature and decreasing gravity. We find several lines that vary with luminosity, but not temperature: Si I (1.59 μm), Sr (1.033 μm), Fe+Cr+Si+CN (1.16 μm), Fe+Ti (1.185 μm), Fe+Ti (1.196 μm), Ti+Ca (1.28 μm), and Mn (1.29 μm). Good markers of CN enhancement are the Fe+Si+CN line at 1.087 μm and CN line at 1.093 μm. Using these lines, at the resolution of SpeX, it is possible to separate RSGs and giants. Contaminant O-rich Mira and S-type AGBs are recognized by strong molecular features due to water vapor features, TiO band heads, and/or ZrO absorption. Among the 42 candidate RSGs that we observed, all but one were found to be late types. Twenty-one have EWs consistent with those of RSGs, 16 with those of O-rich Mira AGBs, and one with an S-type AGB. These infrared results open new, unexplored, potential for searches at low resolution of RSGs in the highly obscured innermost regions of the Milky Way.

Keywords: Late-type supergiant stars, Massive stars, Stellar evolution, Infrared astronomy
Hot Degenerates in the MCT Survey. III. A Sample of White Dwarf Stars in the Southern Hemisphere. We present optical spectra of 144 white dwarfs detected in the Montreal-Cambridge-Tololo colorimetric survey, including 120 DA, 12 DB, 4 DO, 1 DQ, and 7 DC stars. We also perform a model atmosphere analysis of all objects in our sample using the so-called spectroscopic technique, or the photometric technique in the case of DC white dwarfs. The main objective of this paper is to contribute to the ongoing effort of confirming spectroscopically all white dwarf candidates in the Gaia survey, in particular in the southern hemisphere. All our spectra are made available in the Montreal White Dwarf Database.

Keywords: Surveys, White dwarf stars, Fundamental parameters of stars
The Rise and Fall of the Eclipsing Binary HS Hydrae. HS Hydrae is a short period eclipsing binary (Porb = 1.57 day) that belongs to a rare group of systems observed to have rapidly changing inclinations. This evolution is due to a third star on an intermediate orbit, and results in significant differences in eclipse depths and timings year to year. Zasche &amp; Paschke revealed that HS Hydrae's eclipses were rapidly fading from view, predicting they would cease around 2022. Using 25 days of photometric data from Sector 009 of the Transiting Exoplanet Survey Satellite (TESS), we find that the primary eclipses for HS Hydrae were only 0.00173 &amp;PlusMinus; 0.00007 mag in depth in March 2019. This data from TESS likely represents the last eclipses detected from HS Hydrae. We also searched the Digitization of the Harvard Astronomical Plate Collection archive for historic data from the system. With a total baseline of over 125 yr, this unique combination of data sets-from photographic plates to precision space-based photometry-allows us to trace the emergence and decay of eclipses from HS Hydrae, and further constrain its evolution. Recent TESS observations from Sector 035 confirm that eclipses have ceased for HS Hya, and we estimate they will begin again in 2195.

Keywords: Eclipsing binary stars, Binary stars
A Possible Dust Origin for an Unusual Feature in Io's Sodium Neutral Clouds. We report the results of model simulations performed to explain the nature of a sodium emission feature in Io Neutral Clouds. The feature was detected via high-resolution spectroscopic observations from the 3.6 m Italian telescope TNG. The emission feature is blueshifted compared to the main emission (the banana-shaped Neutral Cloud of Io) by a few tens of km s-1, and it is most prominent when Io is a few tens of degrees before eclipse behind Jupiters shadow. The feature's morphology changes with time, indicative of a geometrical effect. We constrained its direction, velocity, and column density with a model of sodium atom trajectories under the influence of Io's and Jupiter's gravity, and solar radiation pressure. The model that best explains this emission feature has the atoms injected into the exosphere from the leading/sub-Jovian hemisphere of Io (45°-68° west longitude), with velocities from 50 to 90 km s-1 relative to Io. These trajectories are consistent with those of negatively charged dust grains (radius ~10 nm) accelerated by the corotational electric field of Jupiters magnetosphere. We propose that sputtering of sodium atoms from Na-bearing molecules (NaCl and Na2SO4) in these nanodust grains is the process responsible for our emission feature. Both modeling and observational constraints provide an order-of-magnitude estimate of the sodium production rate of ~1026 s-1. Our work provides another method to monitor the amount of material that Io is supplying to its Neutral Clouds and plasma torus.

Keywords: Planetary magnetospheres, Io, Galilean satellites, Jovian satellites
A Decade of SCUBA-2: A Comprehensive Guide to Calibrating 450 μm and 850 μm Continuum Data at the JCMT. The Submillimetre Common User Bolometer Array 2 (SCUBA-2) is the James Clerk Maxwell Telescope's continuum imager, operating simultaneously at 450 and 850 μm. SCUBA-2 was commissioned in 2009-2011, and since that time, regular observations of point-like standard sources have been performed whenever the instrument is in use. Expanding the calibrator observation sample by an order of magnitude compared to previous work, in this paper we derive updated opacity relations at each wavelength for a new atmospheric extinction correction, analyze the Flux Conversion Factors used to convert instrumental units to physical flux units as a function of date and observation time, present information on the beam profiles for each wavelength, and update secondary calibrator source fluxes. Between 07:00 and 17:00 UTC, the portion of the night that is most stable to temperature gradients that cause dish deformation, the total flux uncertainty and the peak flux uncertainty measured at 450 μm are found to be 14% and 17%, respectively. Measured at 850 μm, the total flux and peak flux uncertainties are 6% and 7%, respectively. The analysis presented in this work is applicable to all SCUBA-2 projects observed since 2011.

Keywords: Observational astronomy, Calibration, Astronomical techniques, Astronomical instrumentation, Ground-based astronomy, Submillimeter astronomy, Astronomical methods
SOAR TESS Survey. II. The Impact of Stellar Companions on Planetary Populations. We present the results of the second year of exoplanet candidate host speckle observations from the SOAR TESS survey. We find 89 of the 589 newly observed TESS planet candidate hosts have companions within 3″, resulting in light-curve dilution, that, if not accounted for, leads to underestimated planetary radii. We combined these observations with those from Paper I to search for evidence of the impact binary stars have on planetary systems. Removing the one-quarter of the targets observed identified as false-positive planet detections, we find that transiting planets are suppressed by nearly a factor of seven in close solar-type binaries, nearly twice the suppression previously reported. The result on planet occurrence rates that are based on magnitude-limited surveys is an overestimation by a factor of two if binary suppression is not taken into account. We also find tentative evidence for similar close binary suppression of planets in M-dwarf systems. Last, we find that the high rates of widely separated companions to hot Jupiter hosts previously reported was likely a result of false-positive contamination in our sample.

Keywords: Exoplanet dynamics, Binary stars, Exoplanet astronomy, Companion stars, Speckle interferometry
A2626 and Friends: Large- and Small-scale Structure. New MMT/Hectospec spectroscopy centered on the galaxy cluster A2626 and covering a ~1.8 deg2 area out to z ~ 0.46 more than doubles the number of galaxy redshifts in this region. The spectra confirm four clusters previously identified photometrically. A2625, which was previously thought to be a close neighbor of A2626, is in fact much more distant. The new data show six substructures associated with A2626 and five more associated with A2637. There is also a highly collimated collection of galaxies and galaxy groups between A2626 and A2637 having at least three and probably four substructures. At larger scales, the A2626-A2637 complex is not connected to the Pegasus-Perseus filament.

Keywords: Galaxy clusters, Abell clusters, Galaxy spectroscopy, Redshift surveys
Preview of Comet C/2021 A1 (Leonard) and Its Encounter with Venus. Long-period comet C/2021 A1 (Leonard) will approach Venus to within 0.029 au on 2021 December 18 and may subsequently graze the planet with its dust trail less than 2 days later. We observed C/2021 A1 with the Lowell Discovery Telescope on 2021 January 13 and March 3, as well as with the Palomar Hale Telescope on 2021 March 20, while the comet was inbound at heliocentric distances of r = 4.97, 4.46, and 4.28 au, respectively. Tail morphology suggests that the dust is optically dominated by ~0.1-1 mm radius grains produced in the prior year. Neither narrowband imaging photometry nor spectrophotometry reveal any definitive gas emission, placing 3σ upper bounds on CN production of ≲1023 molec-1 at both of the latter two epochs. Trajectory analysis indicates that large (≳1 mm) grains ejected at extremely large heliocentric distances (r ≳ 30 au) are most strongly favored to reach Venus. The flux of such meteors on Venus, and thus their potential direct or indirect observability, is highly uncertain, as the comet's dust production history is poorly constrained at these distances but will likely fall well below the meteor flux from comet C/2013 A1 (Siding Spring)'s closer encounter to Mars in 2014 and thus poses a negligible risk to any spacecraft in orbit around Venus. Dust produced in previous apparitions will not likely contribute substantially to the meteor flux, nor will dust from any future activity apart from an unlikely high-speed (≳0.5 km s-1) dust outburst prior to the comet reaching r ≈ 2 au in 2021 September.

Keywords: Comet tails, Long period comets, Venus, Meteor trails