Sazuna/UAT_keywords huggingface dataset:
Evidence for Transparency and Clumps in the Circumbinary Ring of the T Tauri Star V582 Mon (KH 15D). The binary T Tauri star V582 Mon (KH 15D) is surrounded by a tilted and nodally precessing ring of dusty material, which has caused periodic occultations of one or both stars over the last 50 years. Here, we present multi-color time-series photometry (VRIJHK) throughout the 2017/2018 observing season, when the ring was covering the entire orbit of star A and gradually exposing the orbit of star B. We calculate the mean apparent magnitude of star B to be I = 14.08. Besides the periodic eclipses of star B due to its orbital motion, we observed unexpected dips in brightness indicative of partially transparent stellar-sized clumps within the ring. The wavelength dependence of these events is suggestive of extinction by dust grains significantly larger than typical interstellar dust grains. The photometric variability observed while star B is being uncovered by the trailing edge of the ring is not simply the time reversal of the behavior seen when star A was being covered by the leading edge. Whereas the leading edge appeared to be very sharply defined, the trailing edge is "clumpy" and "fuzzy" (transparent), with a more gradual transition in opacity. The clumpiness and transparency of the occulting material provide a unique opportunity to study the properties of dust grains in a likely planet-forming zone.

Keywords: T Tauri stars, Binary stars, Protoplanetary disks, Weak-line T Tauri stars
CO Gas and Dust Outbursts from Centaur 29P/Schwassmann-Wachmann. 29P/Schwassmann-Wachmann is an unusual solar system object. Originally classified as a short-period comet, it is now known as a Centaur that recently transferred to its current orbit, and may become a Jupiter family comet. It has exhibited a dust coma for over 90 yr, and regularly undergoes significant dust outbursts. Carbon monoxide is routinely detected in high amounts and is typically assumed to play a large role in generating the quiescent dust coma and outbursts. To test this hypothesis, we completed two three-month-long observing campaigns of the CO J = 2-1 rotational line using the Arizona Radio Observatory 10 m Submillimeter Telescope during 2016 and 2018-2019, and compared the results to visible magnitudes obtained at the same time. As the Centaur approached its 2019 perihelion, the quiescent dust coma grew ∼45% in brightness, while it is unclear whether the quiescent CO production rate also increased. A doubling of the CO production rate on 2016 February 28.6 UT did not trigger an outburst nor a rise in dust production for at least 10 days. Similarly, two dust outbursts occurred in 2018 while CO production continued at quiescent rates. Two other dust outbursts may show gas involvement. The data indicate that CO and dust outbursts are not always well correlated. This may be explained if CO is not always substantially incorporated with the dust component in the nucleus, or if CO is primarily released through a porous material. Additionally, other minor volatiles or physical processes may help generate dust outbursts.

Keywords: Small Solar System bodies, Comets, Short period comets, Centaur group
Statistical Characterization of Hot Jupiter Atmospheres Using Spitzer's Secondary Eclipses. We report 78 secondary eclipse depths for a sample of 36 transiting hot Jupiters observed at 3.6 and 4.5 μm using the Spitzer Space Telescope. Our eclipse results for 27 of these planets are new, and include highly irradiated worlds such as KELT-7b, WASP-87b, WASP-76b, and WASP-64b, and important targets for James Webb Space Telescope such as WASP-62b. We find that WASP-62b has a slightly eccentric orbit ( $e\cos \omega =0.00614\pm 0.00064 ), and we confirm the eccentricity of HAT-P-13b and WASP-14b. The remainder are individually consistent with circular orbits, but we find statistical evidence for eccentricity increasing with orbital period in our range from 1 to 5 days. Our day-side brightness temperatures for the planets yield information on albedo and heat redistribution, following Cowan &amp; Agol (2011). Planets having maximum day-side temperatures exceeding ∼2200 K are consistent with having zero albedo and a distribution of stellar irradiance uniformly over the day-side hemisphere. Our most intriguing result is that we detect a systematic difference between the emergent spectra of these hot Jupiters as compared to blackbodies. The ratio of observed brightness temperatures, Tb(4.5)/Tb(3.6), increases with equilibrium temperature by 100 ± 24 parts-per-million per Kelvin, over the entire temperature range in our sample (800-2500 K). No existing model predicts this trend over such a large range of temperature. We suggest that this may be due to a structural difference in the atmospheric temperature profiles of real planetary atmospheres as compared to models.

Keywords: Exoplanet astronomy, Exoplanet atmospheres
Stellar Mass and Stellar Mass-to-light Ratio-Color Relations for Low Surface Brightness Galaxies. We estimate the stellar mass for a sample of low surface brightness galaxies (LSBGs) by fitting their multiband spectral energy distributions (SEDs) to the stellar population synthesis model. The derived stellar masses (log M*/M☉) span from 7.1 to 11.1, with a mean of log M*/M☉ = 8.5, which is lower than that for normal galaxies. The stellar mass-to-light ratio (γ*) in each band varies little with the absolute magnitude but increases with higher M*. This trend of γ* with M* is even stronger in bluer bands. In addition, the γ* for our LSBGs slightly declines from the r band to the longer-wavelength bands. The log ${\gamma }_{* }^{j} (j = g, r, i, and z) have relatively tight relations with optical colors of g - r and g - i. Compared with several representative γ*-color relations (MLCRs) from the literature, our MLCRs based on LSBG data are consistently among those literature MLCRs previously defined on diverse galaxy samples, and the existing minor differences between the MLCRs are caused by the differences in the SED model ingredients (including initial mass function, star formation history, and stellar population model), line fitting techniques, galaxy samples, and photometric zero-point, rather than the galaxy surface brightness itself, which distinguishes LSBGs from high surface brightness galaxies. Our LSBGs would be very likely to follow those representative MLCRs previously defined in diverse galaxy populations, if those main ingredients were taken into account.

Keywords: Galaxy masses, Surface photometry, Mass-to-light ratio, Low surface brightness galaxies
Robo-AO M-dwarf Multiplicity Survey: Catalog. We analyze observations from Robo-AO's field M dwarf survey taken on the 2.1 m Kitt Peak telescope and perform a multiplicity comparison with Gaia DR2. Through its laser-guided, automated system, the Robo-AO instrument has yielded the largest adaptive optics M dwarf multiplicity survey to date. After developing an interface to visually identify and locate stellar companions, we selected 11 low-significance Robo-AO detections for follow-up on the Keck II telescope using NIRC2. In the Robo-AO survey we find 553 candidate companions within 4″ around 534 stars out of 5566 unique targets, most of which are new discoveries. Using a position cross-match with DR2 on all targets, we assess the binary recoverability of Gaia DR2 and compare the properties of multiples resolved by both Robo-AO and Gaia. The catalog of nearby M dwarf systems and their basic properties presented here can assist other surveys which observe these stars, such as the NASA TESS mission.

Keywords: M dwarf stars, Multiple stars, Binary stars, Close binary stars, Trinary stars, Visual binary stars, Catalogs
Cloud Atlas: High-precision HST/WFC3/IR Time-resolved Observations of Directly Imaged Exoplanet HD 106906b. HD 106906b is an $\sim 11{M}_{\mathrm{Jup}}, ∼15 Myr old directly imaged exoplanet orbiting at an extremely large distance from its host star. The wide separation (7"11) between HD 106906b and its host star greatly reduces the difficulty in direct-imaging observations, making it one of the most favorable directly imaged exoplanets for detailed characterization. In this paper, we present HST/WFC3/IR time-resolved observations of HD 106906b in the F127M, F139M, and F153M bands. We have achieved ∼1% precision in the lightcurves in all three bands. The F127M lightcurve demonstrates marginally detectable (2.7σ significance) variability with a best-fitting period of 4 hr, while the lightcurves in the other two bands are consistent with flat lines. We construct primary-subtracted deep images and use these images to exclude additional companions to HD 106906 that are more massive than 4 ${M}_{\mathrm{Jup}} and locate at projected distances of more than ∼500 au. We measure the astrometry of HD 106906b in two HST/WFC3 epochs and achieve precisions better than 2.5 mas. The position angle and separation measurements do not deviate from those in the 2004 HST/ACS/HRC images for more than 1σ uncertainty. We provide the HST/WFC3 astrometric results for 25 background stars that can be used as reference sources in future precision astrometry studies. Our observations also provide the first 1.4 μm water band photometric measurement for HD 106906b. HD 106906b's spectral energy distribution and the best-fitting BT-Settl model have an inconsistency in the 1.4 μm water absorption band, which highlights the challenges in modeling atmospheres of young planetary-mass objects.

Keywords: Time series analysis, Exoplanet atmospheric variability, HST photometry, Direct imaging, Astrometry, Exoplanet atmospheres, Near infrared astronomy
MCG+07-20-052: Interacting Dwarf Pair in a Group Environment. We present an observational study of the interacting pair of dwarf galaxies, MCG+07-20-052, in the vicinity of Milky Way mass spiral galaxy NGC 2998. MCG+07-20-052 is located at a sky-projected distance of 105 kpc from NGC 2998 and the two have a relative line-of-sight velocity of 60 km s-1. We observed tidal tail-like extensions on both members (D1 and D2) of the interacting pair MCG+07-20-052. The interacting dwarf galaxies, D1 and D2, have B-band absolute magnitudes of -17.17 and -17.14 mag, respectively, and D2 is significantly bluer than D1. We obtained H I 21 cm line data of the NGC 2998 system using the Giant Metrewave Radio Telescope to get a more detailed view of the neutral hydrogen (H I) emission in the interacting dwarf galaxies and in the galaxy members of the NGC 2998 group. Evidence of a merger between the dwarf galaxies in the MCG+07-20-052 is also present in the H I kinematics and morphology where we find that H I is mostly concentrated around D2, which also shows a higher level of star-forming activity and a bluer g-r color index compared to D1. In addition, we detect extended tenuous H I emission around another member galaxy, NGC 3006, located close to the MCG+07-20-052 pair at a sky-projected distance of 41 kpc. We compare here our results from the MCG+07-20-052 pair NGC 2998 system with other known Large Magellanic Cloud/Small Magellanic Cloud/Milky Way-type systems and discuss the possible origin of the dwarf-dwarf interaction.

Keywords: Draco dwarf galaxy, Interacting galaxies, Star formation, H I line emission
Loose Ends for the Exomoon Candidate Host Kepler-1625b. The claim of an exomoon candidate in the Kepler-1625b system has generated substantial discussion regarding possible alternative explanations for the purported signal. In this work, we examine these possibilities in detail. First, the effect of more flexible trend models is explored, and we show that sufficiently flexible models are capable of attenuating the signal -- although this is an expected byproduct of invoking such models. We also explore trend models using x- and y-centroid positions, and show that there is no data-driven impetus to adopt such models over temporal ones. We quantify the probability that the 500 ppm moon-like dip could be caused by a Neptune-sized transiting planet to be &lt;0.75%. We show that neither autocorrelation, Gaussian processes, nor a Lomb-Scargle periodogram are able to recover a stellar rotation period, demonstrating that K1625 is a quiet star with periodic behavior &lt;200 ppm. Through injection and recovery tests, we find that the star does not exhibit a tendency to introduce false-positive dip-like features above that of pure Gaussian noise. Finally, we address a recent reanalysis by Kreidberg et al. and show that the difference in conclusions is not from differing systematics models but rather the reduction itself. We show that their reduction exhibits, in comparison to the original analysis: (i) slightly higher intraorbit and post-fit residual scatter, (ii) ≃900 ppm larger flux offset at the visit change, (iii) ≃2 times larger y-centroid variations, and (iv) ≃3.5 times stronger flux-centroid correlation coefficient. These points could be explained by larger systematics in their reduction, potentially impacting their conclusions.

Keywords: Exoplanet detection methods, Natural satellites (Extrasolar), Irregular natural satellites (Extrasolar)
Supercatastrophic Disruption of Asteroids in the Context of SOHO Comet, Fireball, and Meteor Observations. Granvik et al. reported an absence of asteroids on orbits with perihelia near the Sun that they attribute to the "supercatastrophic disruption" of these bodies. Here we investigate whether there is evidence for this process among other bodies with similarly low perihelia: near-Earth asteroids, Solar and Heliospheric Observatory (SOHO) comets, and meter- and millimeter-sized meteoroids. We determine that no known near-Earth asteroids have past (last 104 yr) histories residing significantly inside the Granvik et al. limit, indirectly supporting the disruption hypothesis. The exception is asteroid (467372) 2004 LG, which spent 2500 yr within this limit and thus presents a challenge to that theory. Phaethon has a perihelion distance hovering just above the limit and may be undergoing slow disruption, which may be the source of its dust complex. We find that the rate at which ungrouped SOHO comets are observed is consistent with expected rates for the injection of small (25 m) class asteroids into the near-Sun region and suggest that this fraction of the SOHO-observed comet population may in fact be asteroidal in origin. We also find that there is an absence of meter-sized bodies with near-Sun perihelia but an excess of millimeter-sized meteoroids. This implies that if near-Sun asteroids disrupt, they do not simply fragment into meter-sized chunks but ultimately disintegrate into millimeter-sized particles. We propose that the disruption of near-Sun asteroids, as well as the anomalous brightening and destruction processes that affect SOHO comets, occur through meteoroid erosion, that is, the removal of material through impacts by high-speed near-Sun meteoroids.

Keywords: Near-Earth objects, Asteroids, Meteoroids, Solar system, Comets, Kreutz group
Implications of Abiotic Oxygen Buildup for Earth-like Complex Life. One of the chief paradoxes of molecular oxygen (O2) is that it is an essential requirement for multicellular eukaryotes on Earth while simultaneously posing a threat to their survival via the formation of reactive oxygen species. In this paper, the constraints imposed by O2 on Earth-like complex life are invoked to explore whether worlds with abiotic O2 inventories can harbor such organisms. By taking the major O2 sources and sinks of Earth-like planets into account using a simple model, it is suggested that worlds that receive time-averaged X-ray and extreme ultraviolet fluxes that are ≳10 times higher than Earth might not be capable of hosting complex lifeforms because the photolysis of molecules such as water may lead to significant O2 buildup. Methods for testing this hypothesis by searching for anticorrelations between biosignatures and indicators of abiotic O2 atmospheres are described. In the event, however, that life successfully adapts to high-oxygen environments, these worlds could permit the evolution of large and complex organisms.

Keywords: Exoplanet atmospheric composition , Exoplanets, Exoplanet evolution, Stellar physics, Astrobiology, Exoplanet surface characteristics, Biosignatures, Exoplanet atmospheres, Stellar evolution
TOI-677b: A Warm Jupiter (P = 11.2 days) on an Eccentric Orbit Transiting a Late F-type Star. We report the discovery of TOI-677 b, first identified as a candidate in light curves obtained within Sectors 9 and 10 of the Transiting Exoplanet Survey Satellite (TESS) mission and confirmed with radial velocities. TOI-677 b has a mass of ${\text{}}{M}_{{\text{}}p} = ${1.236}_{-0.067}^{+0.069} ${\text{}}{M}_{{\rm{J}}}, a radius of ${\text{}}{R}_{{\text{}}P} = $1.170\pm 0.03 ${\text{}}{R}_{{\rm{J}}}, and orbits its bright host star (V = 9.8 mag) with an orbital period of $11.23660\pm 0.00011 d, on an eccentric orbit with $e=0.435\pm 0.024 . The host star has a mass of ${\text{}}{M}_{\star } = $1.181\pm 0.058 ${\text{}}{M}_{\odot }, a radius of ${\text{}}{R}_{\star } = ${1.28}_{-0.03}^{+0.03} ${\text{}}{R}_{\odot }, an age of ${2.92}_{-0.73}^{+0.80} Gyr and solar metallicity, properties consistent with a main-sequence late-F star with ${T}_{\mathrm{eff}}=6295\pm 77 K. We find evidence in the radial velocity measurements of a secondary long-term signal, which could be due to an outer companion. The TOI-677 b system is a well-suited target for Rossiter-Mclaughlin observations that can constrain migration mechanisms of close-in giant planets.

Keywords: Exoplanets, Exoplanet astronomy, Planet hosting stars, Radial velocity, Transit photometry, Extrasolar gaseous giant planets
A New Method for Deriving Composition of S-type Asteroids from Noisy and Incomplete Near-infrared Spectra. The surface composition of S-type asteroids can be determined using band parameters extracted from their near-infrared (NIR) spectra (0.7-2.50 μm) along with spectral calibrations derived from laboratory samples. In the past, these empirical equations have been obtained by combining NIR spectra of meteorite samples with information about their composition and mineral abundance. For these equations to give accurate results, the characteristics of the laboratory spectra they are derived from should be similar to those of asteroid spectral data (i.e., similar signal-to-noise ratio (S/N) and wavelength range). Here we present new spectral calibrations that can be used to determine the mineral composition of ordinary chondrite-like S-type asteroids. Contrary to previous work, the S/N of the ordinary chondrite spectra used in this study has been decreased to recreate the S/N typically observed among asteroid spectra, allowing us to obtain more realistic results. In addition, the new equations have been derived for five wavelength ranges encompassed between 0.7 and 2.50 μm, making it possible to determine the composition of asteroids with incomplete data. The new spectral calibrations were tested using band parameters measured from the NIR spectrum of asteroid (25143) Itokawa, and comparing the results with laboratory measurements of the returned samples. We found that the spectrally derived olivine and pyroxene chemistry, which are given by the molar contents of fayalite (Fa) and ferrosilite (Fs), are in excellent agreement with the mean values measured from the samples (Fa28.6±1.1 and Fs23.1±2.2), with a maximum difference of 0.6 mol% for Fa and 1.4 mol% for Fs.

Keywords: Meteorites, Asteroids
The Dynamics of Interstellar Asteroids and Comets within the Galaxy: An Assessment of Local Candidate Source Regions for 1I/'Oumuamua and 2I/Borisov. The low velocity of interstellar asteroid 1I/'Oumuamua with respect to our galaxy's local standard of rest implies that it is young. Adopting the young age hypothesis, we assess possible origin systems for this interstellar asteroid and for 2I/Borisov, though the latter's higher speed means it is unlikely to be young. First, their past trajectories are modeled under gravitational scattering by galactic components ("disk heating") to assess how far back one can trace them. The stochastic nature of disk heating means that a back integration can only expect to be accurate to within 15 pc and 2 km s-1 at -10 Myr, dropping steeply to 400 pc and 10 km s-1 at -100 Myr, sharply limiting our ability to determine a precise origin. Nevertheless, we show that 'Oumuamua's origin system likely is currently within 1 kpc of Earth, in the local Orion Arm. Second, we back integrate 'Oumuamua's trajectory in order to assess source regions, emphasizing young systems and moving groups. Though disk heating allows for only a statistical link to source regions, 'Oumuamua passed through a considerable subset of the Carina and Columba moving groups when those groups were forming. This makes them perhaps the most plausible source region, if 'Oumuamua was ejected during planet formation or via intra-cluster interactions. We find three stars in the Ursa Major group, one brown dwarf, and seven other stars to have plausible encounters with 2I/Borisov, within 2 pc and 30 km s-1. These encounters' high relative speeds mean none are likely to be the home of 2I/Borisov.

Keywords: Comets, Asteroids, Milky Way Galaxy
Asteroids' Size Distribution and Colors from HITS. We report the observations of solar system objects during the 2015 campaign of the High cadence Transient Survey (HiTS). We found 5740 bodies (mostly Main Belt asteroids), 1203 of which were detected in different nights and in g' and r'. Objects were linked in the barycenter system and their orbital parameters were computed assuming Keplerian motion. We identified 6 near Earth objects, 1738 Main Belt asteroids and 4 Trans-Neptunian objects. We did not find a g'-r' color-size correlation for 14 &lt; Hg' &lt; 18 (1 &lt; D &lt; 10 km) asteroids. We show asteroids' colors are disturbed by HiTS' 1.6 hr cadence and estimate that observations should be separated by at most 14 minutes to avoid confusion in future wide-field surveys like LSST. The size distribution for the Main Belt objects can be characterized as a simple power law with slope ∼0.9, steeper than in any other survey, while data from the 2014 HiTS campaign has a distribution consistent with previous ones (slopes ∼0.68 at the bright end and ∼0.34 at the faint end). This difference is likely due to the ecliptic distribution of the Main Belt since the 2015 campaign surveyed farther from the ecliptic than did 2014's and most previous surveys.

Keywords: Main belt asteroids, Sky surveys, Photometry
Arecibo Radar Astrometry of the Galilean Satellites from 1999 to 2016. Harmon et al. Arecibo radar observations from 1992 provided some of the most precise line-of-sight distance (ranging) measurements of Ganymede and Callisto to date. We report 18 new ranges obtained at Arecibo from 1999 to 2016, among which are the first measurements of Io and Europa. We also report accompanying line-of-sight velocity (Doppler frequency) measurements. In 2015, we detected Europa, Ganymede, and Callisto with time-delay (range) resolutions as fine as 10 μs (1.5 km) while Io was detected with 70 μs (10.5 km) resolution. We estimated residuals for the radar measurements with respect to the latest JPL satellite ephemeris JUP310 and planetary ephemeris DE438. We found that the rms of the time-delay residuals are 29 μs for Io, 21 μs for Europa, 58 μs for Ganymede, and 275 μs for Callisto. When normalized by the measurement uncertainties, these correspond to the rms of 0.82, 1.25, 2.17, and 3.17 respectively. As such, the orbit of Callisto has the largest residuals and may benefit from an orbital update that will use radar astrometry. All Doppler residuals were small and consistent with their 1σ uncertainties.

Keywords: Galilean satellites, Astrometry, Radar astronomy