Sazuna/UAT_keywords huggingface dataset:
IRAS Minor Planet Survey (IMPS) Data Set V6.0. The V6.0 version of this data set comprises the 2002 Supplemental IRAS Minor Planet Survey (SIMPS) which presents additional and revised diameters and albedos for asteroids detected by the 1983 IRAS mission. This version supersedes versions 1.0 through 5.0, which represent the original 1992 IRAS Minor Planet Survey (IMPS).

Keywords: Asteroids
TNO and Centaur Diameters, Albedos, and Densities Bundle V1.0. This data set is a compilation of published diameters, albedos, and densities for Transneptunian Objects (TNOs) and Centaurs. A total of 194 objects are listed, many with more than one entry. This version covers published values through 31 March 2018.

Keywords: Centaur group, Trans-Neptunian objects
Saturn Small Moon Shape Models Bundle V1.0. Digital shape models have been constructed from Cassini Imaging Science Subsystem (ISS) data for eleven of the small satellites of Saturn and delivered to the Planetary Data System. These satellites are: Pan, Daphnis, Atlas, Prometheus, Pandora, Epimetheus, Janus, Telesto, Calypso, Helene, and Hyperion. These models typically have uncertainties well under 0.5 km. They are appropriate for global geometric, geologic, and geophysical studies, and regional slope and topography study. They are useful in studying morphologies of only the relatively largest-sized craters. Studies based on early versions of these shape models are in Thomas et al., 2013.

Keywords: Saturnian satellites
The Fermi Paradox and the Aurora Effect: Exo-civilization Settlement, Expansion, and Steady States. We model the settlement of the Galaxy by space-faring civilizations in order to address issues related to the Fermi Paradox. We are motivated to explore the problem in a way that avoids assumptions about the agency (i.e., questions of intent and motivation) of any exo-civilization seeking to settle other planetary systems. We begin by considering the speed of an advancing settlement front to determine if the Galaxy can become inhabited with space-faring civilizations on timescales shorter than its age. Our models for the front speed include the directed settlement of nearby settleable systems through the launching of probes with a finite velocity and range. We also include the effect of stellar motions on the long-term behavior of the settlement front which adds a diffusive component to its advance. As part of our model we also consider that only a fraction, f, of planets will have conditions amenable to settlement by the space-faring civilization. The results of these models demonstrate that the Milky Way can be readily filled-in with settled stellar systems under conservative assumptions about interstellar spacecraft velocities and launch rates. We then move on to consider the question of the Galactic steady state achieved in terms of the fraction X of settled planets. We do this by considering the effect of finite settlement civilization lifetimes on the steady states. We find a range of parameters for which 0 &lt; X &lt; 1, i.e., the Galaxy supports a population of interstellar space-faring civilizations even though some settleable systems are uninhabited. In addition we find that statistical fluctuations can produce local overabundances of settleable worlds. These generate long-lived clusters of settled systems immersed in large regions that remain unsettled. Both results point to ways in which Earth might remain unvisited in the midst of an inhabited galaxy. Finally we consider how our results can be combined with the finite horizon for evidence of previous settlements in Earth’s geologic record. Using our steady-state model we constrain the probabilities for an Earth visit by a settling civilization before a given time horizon. These results break the link between Hart’s famous “Fact A” (no interstellar visitors on Earth now) and the conclusion that humans must, therefore, be the only technological civilization in the Galaxy. Explicitly, our solutions admit situations where our current circumstances are consistent with an otherwise settled, steady-state galaxy.

Keywords: Milky Way evolution, Astrobiology, Galaxy evolution
Identification of Stellar Flares Using Differential Evolution Template Optimization. We explore methods for the identification of stellar flare events in irregularly sampled data of ground-based time domain surveys. In particular, we describe a new technique for identifying flaring stars, which we have implemented in a publicly available Python module called “PyVAN.” The approach uses the Differential Evolution algorithm to optimize parameters of empirically derived light curve templates for different types of stars to fit a candidate light curve. The difference of the likelihoods that these best-fit templates produced the observed data is then used to delineate targets that are well-explained by a flare template but simultaneously poorly explained by templates of common contaminants. By testing on light curves of known identity and morphology, we show that our technique is capable of recovering flaring status in 69% of all light curves containing a flare event above thresholds drawn to include &lt;1% of any contaminant population. By applying to Palomar Transient Factory data, we show consistency with prior samples of flaring stars, and identify a small selection of candidate flaring G-type stars for possible follow-up.

Keywords: Astronomy software, Eruptive variable stars, Variable stars, Flare stars
Untangling the Galaxy. I. Local Structure and Star Formation History of the Milky Way. Gaia DR2 provides unprecedented precision in measurements of the distance and kinematics of stars in the solar neighborhood. Through applying unsupervised machine learning on DR2's 5D data set (3D position + 2D velocity), we identify a number of clusters, associations, and comoving groups within 1 kpc and | b| &lt; 30^\circ (many of which have not been previously known). We estimate their ages with the precision of ∼0.15 dex. Many of these groups appear to be filamentary or string-like, oriented in parallel to the Galactic plane, and some span hundreds of parsec in length. Most of these string lack a central cluster, indicating that their filamentary structure is primordial, rather than the result of tidal stripping or dynamical processing. The youngest strings (&lt;100 Myr) are orthogonal to the Local Arm. The older ones appear to be remnants of several other arm-like structures that cannot be presently traced by dust and gas. The velocity dispersion measured from the ensemble of groups and strings increase with age, suggesting a timescale for dynamical heating of ∼300 Myr. This timescale is also consistent with the age at which the population of strings begins to decline, while the population in more compact groups continues to increase, suggesting that dynamical processes are disrupting the weakly bound string populations, leaving only individual clusters to be identified at the oldest ages. These data shed a new light on the local galactic structure and a large-scale cloud collapse.

Keywords: Stellar ages, Stellar kinematics, Galaxy structure, Milky Way dynamics, Stellar associations, Star clusters
The X-Ray-resolved Supernova Remnant S8 in the Dwarf Irregular Galaxy IC 1613. We conducted an observation of the nearby irregular galaxy IC 1613 with the Chandra X-ray Observatory using the S3 chip of the Advanced CCD Imaging Spectrometer (ACIS) with an effective exposure time of 49.9 ks. The observation primarily targeted the extensive bubble and star formation region in the northeast quadrant of the galaxy. The only known supernova remnant (SNR) in IC 1613, S8, is also the galaxy’s most luminous X-ray source (L X(0.3-8 keV) ∼5-6 × 1036 erg s-1). We resolve the SNR with Chandra and compare its nearly circular X-ray morphology with Hα and radio images. We assign an upper limit on the luminosity of any possible associated compact central object of ≈4 × 1035 erg s-1 (0.3-8 keV band) and conclude that we would detect a Crab-like pulsar but not a Cas A-like object. We infer an age for S8 of ∼3400-5600 yr and compare it to other SNRs in the Local Group. We suggest that S8 is a young composite SNR.

Keywords: Supernova remnants, Irregular galaxies, Dwarf galaxies, X-ray astronomy
Looking for Lurkers: Co-orbiters as SETI Observables. A recently discovered group of nearby co-orbital objects is an attractive location for extraterrestrial intelligence (ETI) to locate a probe to observe Earth while not being easily seen. These near-Earth objects provide an ideal way to watch our world from a secure natural object. That provides resources an ETI might need: materials, a firm anchor, and concealment. These have been little studied by astronomy and not at all by the Search for Extraterrestrial Intelligence (SETI) or planetary radar observations. I describe the objects found thus far and propose both passive and active observations of them as possible sites for extraterrestrial (ET) probes.

Keywords: Near-Earth objects, Trojan asteroids, Earth trojans
Two Long-period Cataclysmic Variable Stars: ASASSN-14ho and V1062 Cyg. We report spectroscopy and photometry of the cataclysmic variable stars ASASSN-14ho and V1062 Cyg. Both are dwarf novae with spectra dominated by their secondary stars, which we classify approximately as K4 and M0.5, respectively. Their orbital periods, determined mostly from the secondary stars’ radial velocities, proved to be nearly identical, respectively 350.14 ± 0.15 and 348.25 ± 0.60 minutes. The Hα emission line in V1062 Cyg displays a relatively sharp emission component that tracks the secondary’s motion, which may arise on the irradiated face of the secondary; this is not often seen and may indicate an unusually strong flux of ionizing radiation. Both systems exhibit double-peaked orbital modulation consistent with ellipsoidal variation from the changing aspect of the secondary. We model these variations to constrain the orbital inclination i, and estimate approximate component masses based on i and the secondary velocity amplitude K 2.

Keywords: Close binary stars, Ellipsoidal variable stars, Cataclysmic variable stars, Dwarf novae
Spitzer  Phase Curves of KELT-1b and the Signatures of Nightside Clouds in Thermal Phase Observations. We observed two full orbital phase curves of the transiting brown dwarf KELT-1b, at 3.6 and 4.5 μm, using the Spitzer Space Telescope. Combined with previous eclipse data from Beatty et al., we strongly detect KELT-1b’s phase variation as a single sinusoid in both bands, with amplitudes of 964 ± 36 ppm at 3.6 μm and 979 ± 54 ppm at 4.5 μm, and confirm the secondary eclipse depths measured by Beatty et al. We also measure noticeable eastward hotspot offsets of 28.°4 ± 3.°5 at 3.6 μm and 18.°6 ± 5.°2 at 4.5 μm. Both the day-night temperature contrasts and the hotspot offsets we measure are in line with the trends seen in hot Jupiters, though we disagree with the recent suggestion of an offset trend by Zhang et al. Using an ensemble analysis of Spitzer phase curves, we argue that nightside clouds are playing a noticeable role in modulating the thermal emission from these objects, based on: (1) the lack of a clear trend in phase offsets with equilibrium temperature, (2) the sharp day-night transitions required to have non-negative intensity maps, which also resolves the inversion issues raised by Keating &amp; Cowan, (3) the fact that all the nightsides of these objects appear to be at roughly the same temperature of 1000 K, while the dayside temperatures increase linearly with equilibrium temperature, and (4) the trajectories of these objects on a Spitzer color-magnitude diagram, which suggest colors only explainable via nightside clouds.

Keywords: Exoplanet atmospheres, Brown dwarfs, Hot Jupiters
Speckle Observations and Orbits of Multiple Stars. We report results of speckle-interferometric monitoring of visual hierarchical systems using the newly commissioned instrument NN-EXPLORE Exoplanet and Stellar Speckle Imager at the 3.5 m WIYN telescope. During one year, 390 measurements of 129 resolved subsystems were made, while some targets were unresolved. Using our astrometry and archival data, we computed 36 orbits (27 for the first time). Spectro-interferometric orbits of seven pairs are determined by combining positional measurements with radial velocities measured, mostly, with the Center for Astrophysics digital speedometers. For the hierarchical systems HIP 65026 (periods 49 and 1.23 yr) and HIP 85209 (periods 34 and 1.23 yr) we determined both the inner and the outer orbits using astrometry and radial velocities and measured the mutual orbit inclinations of 11.°3 ± 1.°0 and 12.°0 ± 3.°0, respectively. Four bright stars are resolved for the first time; two of those are triple systems. Several visual subsystems announced in the literature are shown to be spurious. We note that subsystems in compact hierarchies with outer separations less than 100 au tend to have less eccentric orbits compared to wider hierarchies.

Keywords: Spectroscopic binary stars, Trinary stars, Visual binary stars, Speckle interferometry
WISE J072003.20-084651.2B is a Massive T Dwarf. We present individual dynamical masses for the nearby M9.5+T5.5 binary WISE J072003.20-084651.2AB, a.k.a. Scholz’s star. Combining high-precision Canada-France-Hawaii Telescope/WIRCam photocenter astrometry and Keck adaptive optics resolved imaging, we measure the first high-quality parallactic distance ({6.80}-0.06+0.05 pc) and orbit ({8.06}-0.25+0.24yr period) for this system composed of a low-mass star and brown dwarf. We find a moderately eccentric orbit (e={0.240}-0.010+0.009), incompatible with previous work based on less data, and dynamical masses of 99 ± 6 {M}Jup} and 66 ± 4 {M}Jup} for the two components. The primary mass is marginally inconsistent (2.1σ) with the empirical mass-magnitude-metallicity relation and models of main-sequence stars. The relatively high mass of the cold ({T}eff}=1250+/- 40 K) brown dwarf companion indicates an age older than a few gigayears, in accord with age estimates for the primary star, and is consistent with our recent estimate of ≈70 {M}Jup} for the stellar/substellar boundary among the field population. Our improved parallax and proper motion, as well as an orbit-corrected system velocity, improve the accuracy of the system’s close encounter with the solar system by an order of magnitude. WISE J0720-0846AB passed within 68.7 ± 2.0 kau of the Sun 80.5 ± 0.7 kyr ago, passing through the outer Oort cloud where comets can have stable orbits.

Keywords: M dwarf stars, Brown dwarfs, Astrometric binary stars, Astrometry, Visual binary stars, T dwarfs
Near-resonance in a System of Sub-Neptunes from TESS. We report the Transiting Exoplanet Survey Satellite detection of a multi-planet system orbiting the V = 10.9 K0 dwarf TOI-125. We find evidence for up to five planets, with varying confidence. Three transit signals with high signal-to-noise ratio correspond to sub-Neptune-sized planets (2.76, 2.79, and 2.94 R ⊕), and we statistically validate the planetary nature of the two inner planets (P  b  = 4.65 days, P  c  = 9.15 days). With only two transits observed, we report the outer object (P .03 = 19.98 days) as a planet candidate with high signal-to-noise ratio. We also detect a candidate transiting super-Earth (1.4 R ⊕) with an orbital period of only 12.7 hr and a candidate Neptune-sized planet (4.2 R ⊕) with a period of 13.28 days, both at low signal-to-noise ratio. This system is amenable to mass determination via radial velocities and transit-timing variations, and provides an opportunity to study planets of similar size while controlling for age and environment. The ratio of orbital periods between TOI-125 b and c (P  c /P  b  = 1.97) is slightly lower than an exact 2:1 commensurability and is atypical of multiple planet systems from Kepler, which show a preference for period ratios just wide of first-order period ratios. A dynamical analysis refines the allowed parameter space through stability arguments and suggests that despite the nearly commensurate periods, the system is unlikely to be in resonance.

Keywords: Mini Neptunes, Transit photometry, Super Earths, Exoplanets
Searching for Black Hole Candidates by LAMOST and ASAS-SN. Most dynamically confirmed stellar-mass black holes (BHs) and their candidates were originally selected from X-ray outbursts. In the present work, we search for BH candidates in the Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) survey using the spectra along with photometry from the All Sky Automated Survey for SuperNovae (ASAS-SN), where the orbital period of the binary may be revealed by the periodic light curve, such as the ellipsoidal modulation type. Our sample consists of nine binaries, where each source contains a giant star with large radial velocity variation ({{Δ }}{V}{{R}}≳ 70 {km} {{{s}}}-1) and periods known from light curves. We focus on the nine sources with long periods (T ph &gt; 5 days) and evaluate the mass M 2 of the optically invisible companion. Since the observed ΔV R from only a few repeating spectroscopic observations is a lower limit of the real amplitude, the real mass M 2 can be significantly higher than the current evaluation. It is likely an efficient method to place constraints on M 2 by combining ΔV R from LAMOST and T ph from ASAS-SN, particularly by the ongoing LAMOST Medium Resolution Survey.

Keywords: Stellar photometry, Compact binary stars, Stellar mass black holes, Radial velocity, Stellar spectral types
Observation, Modern Light-curve Analysis, and 89 yr Period Study of the Short-period Algol, AE Cassiopeia. AE Cas was observed some 40 yr ago by Srivastava &amp; Kandpal and was analyzed by Kopal’s Fourier frequency -domain technique. No further precision observations have taken place until the present study, which represents the first modern synthetic analysis of light curves using the 2016 version of the Wilson-Devinney (W-D) Program. It was observed in 2015 October 2, 3 and 23, inclusive, at Dark Sky Observatory in North Carolina with the 0.81 m reflector of Appalachian State University and the 0.9 m reflector at Kitt Peak National Observatory remotely through the Southeastern Association for Research in Astronomy (SARA) consortia. V, R c, I c observations were taken. Five times of minimum light were determined from our present observations, which include three primary eclipses and two secondary eclipses. In addition, eight observations at minima were introduced as low weighted times of minimum light from archived All-Sky Automated Survey for Supernovae Variable Star Catalog (ASAS) data and 74 times of minimum light from the literature, some of which were from visual observations. This period study covers an interval of some 89 yr. The period was found to be decaying at a constant rate with a high level of confidence. A VR c I c simultaneous W-D Program solution indicates that the system has a mass ratio somewhat less than unity (q = 0.856 ± 0.001), and a component temperature difference of ∼2060 K. A q-search was performed and the mass ratio minimized at the above value. The large temperature difference in the components verifies that the binary is not yet in contact. No spots were needed for the solution. The fill-out of our model is 83.2% for the primary component (smaller radius) and 99.1% for the secondary component. So, it is near a classical Algol configuration.

Keywords: Algol variable stars, Interacting binary stars, Detached binary stars, Eclipsing binary stars, Contact binary stars, Stellar evolution
Spectroscopic Follow-up of Discoveries from the NEOWISE Proper Motion Survey. We present low-resolution near-infrared spectra of discoveries from an all-sky proper motion search conducted using multi-epoch data from the Wide-field Infrared Survey Explorer. Using the data from NEOWISE, along with the AllWISE catalog, Schneider et al. conducted an all-sky proper motion survey to search for nearby objects with high proper motions. Here, we present a follow-up spectroscopic survey of 65 of their discoveries, which focused primarily on potentially nearby objects (d &lt; 25 pc), candidate late-type brown dwarfs (≥L7), and subdwarf candidates. We found 31 new M dwarfs, 18 new L dwarfs, and 11 new T dwarfs. Of these, 13 are subdwarfs, including one new sdL1 and two new sdL7s. Eleven of these discoveries, with spectral types ranging from M7 to T7 (including one subdwarf) are predicted to be within 25 pc, adding to the number of known objects in the solar neighborhood. We also discovered three new early-type T subdwarf candidates, one sdT1, one sdT2, and one sdT3, which would increase the number of known early-type T subdwarfs from two to five.

Keywords: M dwarf stars, Brown dwarfs, M subdwarf stars, L dwarfs, Infrared astronomy, L subdwarfs, Low mass stars, Spectroscopy, T subdwarfs, T dwarfs
The Contribution of Dwarf Planets to the Origin of Jupiter Family Comets. We explore the long-term evolution of a bias-free orbital representation of the cometary nuclei (with diameters above 2 km) of the Kuiper Belt, using the so-called L7 synthetic model from CFEPS, which consists of three dynamical subpopulations: the Classical, the Resonant, and the Scattering. The dynamical evolution of belt particles is studied under the gravitational influence of the Sun and the four giant planets, as well as of the 34 largest known trans-Neptunian objects (i.e., those with H  V  &lt; 4). Here, we indistinctly call Dwarf Planets (DPs) to the full sample of 34 large TNOs. Over a 1 Gyr timescale, we analyze the secular influence of the DPs over Kuiper Belt disk particles and their contribution to the injection rate of new visible Jupiter Family Comets (JFCs). We find that DPs globally increase the number of JFCs by 12.6%, when compared with the comets produced by the giant planets alone. When considering each population separately, we find the increment produced by DPs to be 17%, 12%, and 3% for the Classical, Resonant, and Scattering populations, respectively. Given the rate of escapes from the Kuiper Belt, we find upper limits to the number of objects in each population required to maintain the JFCs in steady state; the results are 55.9 × 106, 78.5 × 106, and 274.3 × 106 for the Scattering, Resonant, and Classical populations, respectively. Finally, we find that the Plutinos are the most important source of comets that were originally in a resonant configuration, where the presence of Pluto alone enhances by 10% the number of JFCs.

Keywords: Kuiper belt, Small Solar System bodies, Short period comets, Solar system, Computational methods, Dwarf planets, Trans-Neptunian objects, Dynamical evolution