adsabs/SciX_UAT_keywords huggingface dataset:
Inner Habitable Zone Boundary for Eccentric Exoplanets

The climate of a planet can be strongly affected by its eccentricity due to variations in the stellar flux. There are two limits for the dependence of the inner habitable zone boundary (IHZ) on eccentricity: (1) the mean stellar flux approximation ( ${S}_{{\rm{IHZ}}}\propto \sqrt{1-{e}^{2}}$ ), in which the temperature is approximately constant throughout the orbit, and (2) the maximum stellar flux approximation (S IHZ ∝ (1 - e)2), in which the temperature adjusts instantaneously to the stellar flux. Which limit is appropriate is determined by the dimensionless parameter ${\rm{\Pi }}=\tfrac{C}{{BP}}$ , where C is the heat capacity of the planet, P is the orbital period, and $B=\tfrac{\partial {\rm{\Omega }}}{\partial {T}_{s}}$ , where Ω is the outgoing long-wave radiation and T s is the surface temperature. We use the Buckingham Π theorem to derive an analytical function for the IHZ in terms of eccentricity and Π. We then build a time-dependent energy balance model to resolve the surface temperature evolution and constrain our analytical result. We find that Π must be greater than about ~1 for the mean stellar flux approximation to be nearly exact and less than about ~0.01 for the maximum stellar flux approximation to be nearly exact. In addition to assuming a constant heat capacity, we also consider the effective heat capacity including latent heat (evaporation and precipitation). We find that for planets with an Earthlike ocean, the IHZ should follow the mean stellar flux limit for all eccentricities. This work will aid in the prioritization of potentially habitable exoplanets with nonzero eccentricity for follow-up characterization.

Keywords: exoplanet astronomy; exoplanets; elliptical orbits; habitable zone; habitable planets
Rotational Desorption of Ice Mantles from Suprathermally Rotating Grains around Young Stellar Objects

Ice mantles on dust grains play a central role in astrochemistry. Water and complex organic molecules (COMs) are thought to first form on the ice mantles and subsequently are released into the gas phase due to star-formation activity. However, the critical question is whether ice mantles can survive stellar radiation when grains are being heated from {T}_{d}∼ 10 K to ≳100 K. In this paper, we first study the effect of suprathermal grain rotation driven by the intense radiation of young stellar objects on the ice mantles. We find that the entire ice mantles can be disrupted into small fragments by centrifugal stress before the water ice and COMs desorb via thermal sublimation. We then study the consequence of resulting ice fragments and find that tiny fragments of radius a ≲ 10 Å exhibit a transient release of COMs due to thermal spikes, whereas larger fragments can facilitate thermal sublimation at much higher rates than from the original icy grain, or the same rate but with temperatures of ∼20-40 K lower. We find that rotational desorption is efficient for hot cores/corinos from the inner to outer regions where the temperature drops to T_{gas}∼ 40 K and n_{H} ∼ 104 cm-1. We discuss the implications of this mechanism for desorption of COMs and water ice in various environments, including outflow cavity walls, photodissociation regions, and protoplanetary disks. Finally, we show that very large aggregate grains can be disrupted into individual icy grains via a rotational disruption mechanism, followed by rotational desorption of ice mantles.

Keywords: interstellar dust; dense interstellar clouds; molecule formation; interstellar molecules; molecule destruction; astrochemistry; star formation; protostars
Fastcc: Fast Color Corrections for Broadband Radio Telescope Data

Broadband receiver data need color corrections applying to correct for the different source spectra across their wide bandwidths. The full integration over a receiver bandpass may be computationally expensive and redundant when repeated many times. Color corrections can be applied, however, using a simple quadratic fit based on the full integration instead. Here we describe fastcc and interpcc, quick Python and IDL codes that return, respectively, color correction coefficients for different power-law spectral indices and modified blackbodies for various Cosmic Microwave Background related experiments. The codes are publicly available, and can be easily extended to support additional telescopes.

Keywords: cmbr detectors; radio receivers; astronomy data analysis; photometry
A Multiwavelength Study of the Cool Core Cluster MACS J1447.4+0827

Clusters of galaxies are outstanding laboratories for understanding the physics of supermassive black hole (SMBH) feedback. Here we present the first Chandra, Karl G. Jansky Very Large Array, and Hubble Space Telescope analysis of MACS J1447.4+0827 (z = 0.3755), one of the strongest cool core clusters known, in which extreme feedback from its central SMBH is needed to prevent the hot intracluster gas from cooling. Using this multiwavelength approach, including 70 ks of Chandra X-ray observations, we detect the presence of collimated jetted outflows that coincide with a southern and a northern X-ray cavity. The total mechanical power associated with these outflows (Pcav ≈ 6 × 1044 erg s-1) is roughly consistent with the energy required to prevent catastrophic cooling of the hot intracluster gas (Lcool = 1.71 ± 0.01 × 1045 erg s-1 for tcool = 7.7 Gyr), implying that powerful SMBH feedback was in place several Gyr ago in MACS J1447.7+0827. In addition, we detect the presence of a radio minihalo that extends over 300 kpc in diameter (P1.4GHz = 3.0 ± 0.3 × 1024 W Hz-1). The X-ray observations also reveal an ∼20 kpc plumelike structure that coincides with optical dusty filaments that surround the central galaxy. Overall, this study demonstrates that the various physical phenomena occurring in the most nearby clusters of galaxies are also occurring in their more distant analogs.

Keywords: black hole physics; high energy astrophysics; active galactic nuclei; radio jets; relativistic jets; galaxy clusters; x-ray astronomy; hubble space telescope; optical observatories
Coherence of Ion Cyclotron Resonance in Damped Ion Cyclotron Waves in Space Plasmas

Ion cyclotron resonance is one of the fundamental energy-conversion processes through field-particle interaction in collisionless plasmas. However, the key evidence for ion cyclotron resonance (i.e., the coherence between electromagnetic fields and the ion phase-space density) and the resulting damping of ion cyclotron waves (ICWs) has not yet been directly observed. Investigating the high-quality measurements of space plasmas by the Magnetospheric Multiscale (MMS) satellites, we find that both the wave electromagnetic field vectors and the bulk velocity of the disturbed ion velocity distribution rotate around the background magnetic field. Moreover, we find that the absolute gyrophase angle difference between the center of the fluctuations in the ion velocity distribution functions and the wave electric field vectors falls in the range of (0, 90)°, consistent with an ongoing energy conversion from wave fields to particles. By invoking plasma kinetic theory, we demonstrate that the field-particle correlation for the damped ICWs in our theoretical model matches well with our observations. Furthermore, the wave electric field vectors ( $\delta {{\boldsymbol{E}}}_{\mathrm{wave},\perp }^{{\prime} }$ ), ion current density (δ J i,⊥), and energy transfer rate ( $\delta {{\boldsymbol{J}}}_{{\rm{i}},\perp }\cdot \delta {{\boldsymbol{E}}}_{\mathrm{wave},\perp }^{{\prime} }$ ) exhibit quasiperiodic oscillations, and the integrated work done by the electromagnetic field on the ions is positive, indicating that ions are mainly energized by the perpendicular component of the electric field via cyclotron resonance. Therefore, our combined analysis of MMS observations and kinetic theory provides direct, thorough, and comprehensive evidence for ICW damping in space plasmas.

Keywords: space plasmas; alfven waves; plasma physics
COMAP Early Science. V. Constraints and Forecasts at z 3

We present the current state of models for the z ~ 3 carbon monoxide (CO) line intensity signal targeted by the CO Mapping Array Project (COMAP) Pathfinder in the context of its early science results. Our fiducial model, relating dark matter halo properties to CO luminosities, informs parameter priors with empirical models of the galaxy-halo connection and previous CO (1-0) observations. The Pathfinder early science data spanning wavenumbers k = 0.051-0.62 Mpc-1 represent the first direct 3D constraint on the clustering component of the CO (1-0) power spectrum. Our 95% upper limit on the redshift-space clustering amplitude A clust ≲ 70 μK2 greatly improves on the indirect upper limit of 420 μK2 reported from the CO Power Spectrum Survey (COPSS) measurement at k ~ 1 Mpc-1. The COMAP limit excludes a subset of models from previous literature and constrains interpretation of the COPSS results, demonstrating the complementary nature of COMAP and interferometric CO surveys. Using line bias expectations from our priors, we also constrain the squared mean line intensity-bias product, ${\left\langle {Tb}\right\rangle }_{2}$ ≲ 50 μK2, and the cosmic molecular gas density, ρ H2 < 2.5 × 108 M ⊙ Mpc-3 (95% upper limits). Based on early instrument performance and our current CO signal estimates, we forecast that the 5 yr Pathfinder campaign will detect the CO power spectrum with overall signal-to-noise ratio of 9-17. Between then and now, we also expect to detect the CO-galaxy cross-spectrum using overlapping galaxy survey data, enabling enhanced inferences of cosmic star formation and galaxy evolution history.

Keywords: co line emission; cosmological evolution; high-redshift galaxies; molecular gas; radio astronomy
A New Catalog of Asymptotic Giant Branch Stars in Our Galaxy

We present a new catalog of 11,209 O-rich asymptotic giant branch (AGB) stars and 7172 C-rich AGB stars in our Galaxy, identifying more AGB stars in the bulge component and considering more visual carbon stars. For each object, we cross-identify the Infrared Astronomical Satellite (IRAS), AKARI, Midcourse Space Experiment, Wide-field Infrared Survey Explorer (WISE), Two-Micron All-Sky Survey, and American Association of Variable Star Observers counterparts. We present the new catalog in two parts: one is based on the IRAS PSC for brighter or more isolated objects; the other one is based on the ALLWISE source catalog for less bright objects or objects in crowded regions. We present various infrared two-color diagrams (2CDs) for the sample stars. We find that the theoretical dust shell models can roughly explain the observations of AGB stars on the various IR 2CDs. We investigate IR properties of SiO and OH maser emission sources in the catalog. For Mira variables in the sample stars, we find that the IR colors get redder for longer pulsation periods. We also study infrared variability of the sample stars using the WISE photometric data in the last 12 yr: the ALLWISE multiepoch data and the Near-Earth Object WISE Reactivation 2021 data release. We generate light curves using the WISE data at W1 and W2 bands and compute the Lomb-Scargle periodograms for all of the sample stars. From the WISE light curves, we have found useful variation parameters for 3710 objects in the catalog, for which periods were either known or unknown in previous works.

Keywords: asymptotic giant branch stars; circumstellar dust; long period variable stars; milky way galaxy; infrared astronomy; radiative transfer
A Possible Superbolide Over Don Benito (Spain) in 1926 December 27

We discuss the discovery of a significant meteoric event over Don Benito, Spain, described in two news reports from the regional newspaper "Extremadura." These reports detail intense light, loud noises, and shattered windows in Don Benito during 1926 December. Despite limited information, this research note aims to share the findings with the scientific community for further investigation.

Keywords: bolides
A Metallicity Study of F, G, K, and M Dwarfs in the Coma Berenices Open Cluster from the APOGEE Survey

We present a study of metallicities in a sample of main-sequence stars with spectral types M, K, G, and F (Teff ~3200-6500K and log g ~ 4.3-5.0 dex) belonging to the solar neighborhood young open cluster Coma Berenices. Metallicities were determined using the high-resolution (R = λ/Δ λ ~ 22,500) NIR spectra (λ1.51-λ1.69 μm) of the Sloan Digital Sky Survey IV APOGEE survey. Membership to the cluster was confirmed using previous studies in the literature along with APOGEE radial velocities and Gaia DR2. An LTE analysis using plane-parallel MARCS model atmospheres and the APOGEE DR16 line list was adopted to compute synthetic spectra and derive atmospheric parameters (Teff and log g) for the M dwarfs and metallicities for the sample. The derived metallicities are near-solar and are homogeneous at the level of the expected uncertainties, in particular when considering stars from a given stellar class. The mean metallicity computed for the sample of G, K, and M dwarfs is ⟨[Fe/H]⟩ = +0.04 ± 0.02 dex; however, the metallicities of the F-type stars are slightly lower, by about 0.04 dex, when compared to cooler and less massive members. Models of atomic diffusion can explain this modest abundance dip for the F dwarfs, indicating that atomic diffusion operates in Coma Berenices stars. The [Fe/H] dip occurs in nearly the same effective temperature range as that found in previous analyses of the lithium and beryllium abundances in Coma Berenices.

Keywords: open star clusters; stellar associations; metallicity; stellar diffusion; m dwarf stars; infrared astronomy
Rapid Protoplanet Formation in Vortices: Three-dimensional Local Simulations with Self-gravity

Disk vortices, seen in numerical simulations of protoplanetary disks and found observationally in Atacama Large Millimeter/submillimeter Array and Very Large Array images of these objects, are promising sites for planet formation given their pebble trapping abilities. Previous works have shown a strong concentration of pebbles in vortices, but gravitational collapse has only been shown in low-resolution, two-dimensional, global models. In this Letter, we aim to study the pebble concentration and gravitational collapse of pebble clouds in vortices via high-resolution, three-dimensional, local models. We performed simulations of the dynamics of gas and solids in a local shearing box where the gas is subject to convective overstability, generating a persistent giant vortex. We find that the vortex produces objects of Moon and Mars mass, with a mass function of power-law . The protoplanets grow rapidly, doubling in mass in about five orbits, following pebble accretion rates. The mass range and mass doubling rate are in broad agreement with previous low-resolution global models. We conclude that Mars-mass planetary embryos are the natural outcome of planet formation inside the disk vortices seen in millimeter and radio images of protoplanetary disks.

Keywords: planet formation
The Green Bank North Celestial Cap Survey. VIII. 21 New Pulsar Timing Solutions

We present timing solutions for 21 pulsars discovered in 350 MHz surveys using the Green Bank Telescope (GBT). All were discovered in the Green Bank North Celestial Cap pulsar survey, with the exception of PSR J0957-0619, which was found in the GBT 350 MHz Drift-scan pulsar survey. The majority of our timing observations were made with the GBT at 820 MHz. With a spin period of 37 ms and a 528 days orbit, PSR J0032+6946 joins a small group of five other mildly recycled wide binary pulsars, for which the duration of recycling through accretion is limited by the length of the companion's giant phase. PSRs J0141+6303 and J1327+3423 are new disrupted recycled pulsars. We incorporate Arecibo observations from the NANOGrav pulsar timing array into our analysis of the latter. We also observed PSR J1327+3423 with the Long Wavelength Array, and our data suggest a frequency-dependent dispersion measure. PSR J0957-0619 was discovered as a rotating radio transient, but is a nulling pulsar at 820 MHz. PSR J1239+3239 is a new millisecond pulsar (MSP) in a 4 days orbit with a low-mass companion. Four of our pulsars already have published timing solutions, which we update in this work: the recycled wide binary PSR J0214+5222, the noneclipsing black widow PSR J0636+5128, the disrupted recycled pulsar J1434+7257, and the eclipsing binary MSP J1816+4510, which is in an 8.7 hr orbit with a redback-mass companion.

Keywords: pulsars; pulsar timing method; millisecond pulsars; binary pulsars
von Karman Correlation Similarity of the Turbulent Interplanetary Magnetic Field

A major development underlying much of hydrodynamic turbulence theory is the similarity decay hypothesis due to von Karman and Howarth here extended empirically to magnetic field fluctuations in the solar wind. In similarity decay the second-order correlation experiences a continuous transformation based on a universal functional form and a rescaling of energy and characteristic length. Solar wind turbulence follows many principles adapted from classical fluid turbulence, but previously this similarity property has not been examined explicitly. Here we analyze an ensemble of magnetic correlation functions computed from Advanced Composition Explorer data at 1 au, and demonstrate explicitly that the two-point correlation functions undergo a collapse to a similarity form of the type anticipated from von Karman's hypothesis. This provides for the first time a firm empirical basis for employing the similarity decay hypothesis to the magnetic field, one of the primitive variables of magnetohydrodynamics, and one frequently more accessible from spacecraft instruments. This approach is of substantial utility in space turbulence data analysis, and for adopting von Karman-type heating rates in global and subgrid-scale dynamical modeling.

Keywords: solar wind; interplanetary physics; interplanetary turbulence; plasma astrophysics; magnetohydrodynamics
The Host Galaxy and Rapidly Evolving Broad-line Region in the Changing-look Active Galactic Nucleus 1ES 1927+654

Changing-look active galactic nuclei (AGNs) present an important laboratory to understand the origin and physical properties of the broad-line region (BLR). We investigate follow-up optical spectroscopy spanning ~500 days after the outburst of the changing-look AGN 1ES 1927+654. The emission lines displayed dramatic, systematic variations in intensity, velocity width, velocity shift, and symmetry. Analysis of optical spectra and multiband images indicates that the host galaxy contains a pseudobulge and a total stellar mass of ${3.56}_{-0.35}^{+0.38}\times {10}^{9}\,{M}_{\odot }$ . Enhanced continuum radiation from the outburst produced an accretion disk wind, which condensed into BLR clouds in the region above and below the temporary eccentric disk. Broad Balmer lines emerged ~100 days after the outburst, together with an unexpected, additional component of narrow-line emission. The newly formed BLR clouds then traveled along a similar eccentric orbit (e ≈ 0.6). The Balmer decrement of the BLR increased by a factor of ~4-5 as a result of secular changes in cloud density. The drop in density at late times allowed the production of He I and He II emission. The mass of the black hole cannot be derived from the broad emission lines because the BLR is not virialized. Instead, we use the stellar properties of the host galaxy to estimate ${M}_{\mathrm{BH}}={1.38}_{-0.66}^{+1.25}\times {10}^{6}\,{M}_{\odot }$ . The nucleus reached near or above its Eddington limit during the peak of the outburst. We discuss the nature of the changing-look AGN 1ES 1927+654 in the context of other tidal disruption events.

Keywords: active galactic nuclei; tidal disruption; agn host galaxies
Real-time Likelihood Methods for Improved γ-Ray Transient Detection and Localization

We present a maximum-likelihood (ML) algorithm that is fast enough to detect γ-ray transients in real time on low-performance processors often used for space applications. We validate the routine with simulations and find that, relative to algorithms based on excess counts, the ML method is nearly twice as sensitive, allowing detection of 240%-280% more short γ-ray bursts. We characterize a reference implementation of the code, estimating its computational complexity and benchmarking it on a range of processors. We exercise the reference implementation on archival data from the Fermi Gamma-ray Burst Monitor (GBM), verifying the sensitivity improvements. In particular, we show that the ML algorithm would have detected GRB 170817A even if it had been nearly 4 times fainter. We present an ad hoc but effective scheme for discriminating transients associated with background variations. We show that the onboard localizations generated by ML are accurate, but that refined off-line localizations require a detector response matrix with about 10 times finer resolution than is the current practice. Increasing the resolution of the GBM response matrix could substantially reduce the few-degree systematic uncertainty observed in the localizations of bright bursts.

Keywords: gamma-ray bursts; gamma-ray detectors; gamma-ray telescopes; gamma-ray astronomy; maximum likelihood estimation; likelihood ratio test; algorithms
Weak Mass Loss from the Red Supergiant Progenitor of the Type II SN 2021yja

We present high-cadence optical, ultraviolet (UV), and near-infrared data of the nearby (D ≈ 23 Mpc) Type II supernova (SN) 2021yja. Many Type II SNe show signs of interaction with circumstellar material (CSM) during the first few days after explosion, implying that their red supergiant (RSG) progenitors experience episodic or eruptive mass loss. However, because it is difficult to discover SNe early, the diversity of CSM configurations in RSGs has not been fully mapped. SN 2021yja, first detected within ≈ 5.4 hours of explosion, shows some signatures of CSM interaction (high UV luminosity and radio and x-ray emission) but without the narrow emission lines or early light-curve peak that can accompany CSM. Here we analyze the densely sampled early light curve and spectral series of this nearby SN to infer the properties of its progenitor and CSM. We find that the most likely progenitor was an RSG with an extended envelope, encompassed by low-density CSM. We also present archival Hubble Space Telescope imaging of the host galaxy of SN 2021yja, which allows us to place a stringent upper limit of ≲ 9 M ☉ on the progenitor mass. However, this is in tension with some aspects of the SN evolution, which point to a more massive progenitor. Our analysis highlights the need to consider progenitor structure when making inferences about CSM properties, and that a comprehensive view of CSM tracers should be made to give a fuller view of the last years of RSG evolution.

Keywords: circumstellar matter; core-collapse supernovae; stellar mass loss; supernovae; type ii supernovae