bluuebunny/crossref_metadata_2025_split huggingface dataset:
Mineralogical Criteria for the Parent Asteroid of the “Carbonaceous” Achondrite NWA 6704
Authors: McGraw Allison M. , Reddy Vishnu , Izawa Matthew R. M. , Sanchez Juan A. , Le Corre Lucille , Cloutis Edward A. , Applin Daniel M. , Pearson Neil 
Published: February 2020

Abstract
The unique achondrite meteorite Northwest Africa (NWA) 6704 and its paired samples are fragments of an unknown parent asteroid that experienced large-scale igneous melting early in our solar system’s history. The geochemistry and mineralogy of NWA 6704 show that its parent asteroid has affinities with carbonaceous chondrites and that the precursor materials were relatively oxidized. While large-scale melting has affected the meteorite, there is no evidence for equilibration with a metallic melt. NWA 6704 paired meteorites therefore provide insights into the evolution of planetesimals and bodies that accreted from source materials, possibly in the ice-rich outer solar system. Currently, we lack an understanding of the distribution of potential parent asteroids of the NWA 6704 meteorites. We have undertaken a detailed multiwavelength (0.35–25 μm) spectroscopic and geochemical investigation of NWA 6704 to provide constraints on the potential parent asteroids of these enigmatic meteorites. In comparison with asteroid spectra, NWA 6704 is similar to the S(VI) subtypes of the S-asteroid complex. By using the Bus-DeMeo Taxonomic Classifier, we determine that NWA 6704 has affinities toward V-type (Vesta type) asteroids. We have determined that the parent asteroid of NWA 6704 would be a V-type asteroid that is not dynamically linked to Vesta and also fall in the S(VI) subtype of the Band I center versus Band area ratio diagram. A search in the literature for potential parent bodies yielded one asteroid, (34698) 2001 OD22, as a possible candidate.
A Search for Transiting Planets in the Globular Cluster M4 with K2: Candidates and Occurrence Limits
Authors: Wallace Joshua J. , Hartman Joel D. , Bakos Gáspár Á. 
Published: February 2020

Abstract
We perform a search for transiting planets in the NASA K2 observations of the globular cluster (GC) M4. This search is sensitive to larger orbital periods (P ≲ 35 days, compared to the previous best of P ≲ 16 days), and at the shortest periods, smaller planet radii (R

p
≳ 0.3 R
J, compared to the previous best of R

p
≳ 0.8 R
J) than any previous search for GC planets. Seven planet candidates are presented. An analysis of the systematic noise in our data shows that most, if not all, of these candidates are likely false alarms. We calculate planet occurrence rates assuming our highest significance candidate is a planet and occurrence rate upper limits assuming no detections. We calculate 3σ occurrence rate upper limits of 6.1% for 0.71–2 R
J planets with 1–36 days periods and 16% for 0.36–0.71 R
J planets with 1–10 days periods. The occurrence rates from Kepler, TESS, and radial velocity studies of field stars are consistent with both a nondetection of a planet and detection of a single hot Jupiter in our data. Comparing to previous studies of GCs, we are unable to place a more stringent constraint than Gilliland et al. for the radius–period range they were sensitive to, but do place tighter constraints than both Weldrake et al. and Nascimbeni et al. for the large-radius regimes to which they were sensitive.
Discovery of Two Nearby Post-T Tauri Stellar Associations
Authors: Liu Jiaming , Fang Min , Liu Chao 
Published: February 2020

Abstract
In this work we report the discovery of two new stellar associations in close vicinity of the Sun at roughly 180 and 150 pc. These two associations, u Tau assoc and e Tau assoc, were detected based on their clustering in a multi-dimensional parameter space including α, δ, μ

α
, μ

δ
, and ϖ of Gaia. The fitting of pre-main-sequence model isochrones in their color–magnitude diagrams suggests that the two associations are of about 50 Myr old and the group members lower than ∼0.8 M
⊙ are at the stage of post-T Tauri.
TESS Phase Curve of the Hot Jupiter WASP-19b
Authors: Wong Ian , Benneke Björn , Shporer Avi , Fetherolf Tara , Kane Stephen R. , Ricker George R. , Vanderspek Roland , Seager Sara , Winn Joshua N. , Collins Karen A. , Mireles Ismael , Morris Robert , Tenenbaum Peter , Ting Eric B. , Rinehart Stephen , Villaseñor Jesus Noel 
Published: February 2020

Abstract
We analyze the phase curve of the short-period transiting hot Jupiter system WASP-19, which was observed by the Transiting Exoplanet Survey Satellite (TESS) in Sector 9. WASP-19 is one of only five transiting exoplanet systems with full-orbit phase curve measurements at both optical and infrared wavelengths. We measure a secondary eclipse depth of

ppm and detect a strong atmospheric brightness modulation signal with a semiamplitude of 319 ± 51 ppm. No significant offset is detected between the substellar point and the region of maximum brightness on the dayside. There is also no significant nightside flux detected, which is in agreement with the nightside effective blackbody temperature of

derived from the published Spitzer phase curves for this planet. Placing the eclipse depth measured in the TESS bandpass alongside the large body of previous values from the literature, we carry out the first atmospheric retrievals of WASP-19b’s secondary eclipse spectrum using the SCARLET code. The retrieval analysis indicates that WASP-19b has a dayside atmosphere consistent with an isotherm at T = 2240 ± 40 K and a visible geometric albedo of 0.16 ± 0.04, indicating significant contribution from reflected starlight in the TESS bandpass and moderately efficient day–night heat transport.
Hydrodynamic Escape of Water Vapor Atmospheres near Very Active Stars
Authors: Johnstone C. P. 
Published: February 2020

Abstract
When exposed to the high-energy X-ray and ultraviolet radiation of a very active star, water vapor in the upper atmospheres of planets can be photodissociated and rapidly lost to space. In this paper, I study the chemical, thermal, and hydrodynamic processes in the upper atmospheres of terrestrial planets, concentrating on water-vapor-dominated atmospheres orbiting in the habitable zones of active stars. I consider different stellar activity levels and find very high levels of atmospheric escape in all cases, with the outflowing gas being dominated by atomic hydrogen and oxygen in both their neutral and ion forms. In the lower activity cases, I find that the accumulation of O2 and increases in the D/H ratios in the atmospheres due to mass fractionation are possible, but in the higher activity cases, no mass fractionation takes place. Connecting these results to stellar activity evolution tracks for solar-mass stars, I show that huge amounts of water vapor can be lost, and both the losses and the amount of O2 that can be accumulated in the atmosphere depend sensitively on the star’s initial rotation rate. For an Earth-mass planet in the habitable zone of a low-mass M dwarf, my results suggest that the accumulation of atmospheric O2 is unlikely unless water loss can take place after the star’s most active phase.
Laboratory Calibrations of Fe xii–xiv Line-intensity Ratios for Electron Density Diagnostics
Authors: Arthanayaka Thusitha , Beiersdorfer Peter , Brown Gregory V. , Gu Ming Feng , Hahn Michael , Hell Natalie , Lockard Tom , Savin Daniel W. 
Published: February 2020

Abstract
We have used an electron beam ion trap to measure electron-density-diagnostic line-intensity ratios for extreme ultraviolet lines from Fe xii, xiii, and xiv at wavelengths of ≈185–205 and 255–276 Å. These ratios can be used as density diagnostics for astrophysical spectra and are especially relevant to solar physics. We found that density diagnostics using the Fe xiii 196.53/202.04 and the Fe xiv 264.79/274.21 and 270.52A/274.21 line ratios are reliable using the atomic data calculated with the Flexible Atomic Code (FAC). On the other hand, we found a large discrepancy between the FAC theory and experiment for the commonly used Fe xii (186.85 + 186.88)/195.12 line ratio. These FAC theory calculations give results similar to the data tabulated in CHIANTI, which are commonly used to analyze solar observations. Our results suggest that the discrepancies seen between solar coronal density measurements using the Fe xii (186.85 + 186.88)/195.12 and Fe xiii 196.54/202.04 line ratios are likely due to issues with the atomic calculations for Fe xii.
ALMA Observations of Two Massive and Dense MALT90 Clumps
Authors: Neupane Sudeep , Garay Guido , Contreras Yanett , Guzmán Andrés E. , Rodríguez Luis Felipe 
Published: February 2020

Abstract
We report Atacama Large Millimeter Array observations of 3 mm dust continuum emission and line emission, in HCO+, H13CO+, N2H+, and CH3CN, toward two massive and dense clumps (MDCs) in early but distinct evolutionary phases (prestellar and protostellar), made with the goal of investigating their fragmentation characteristics at angular scales of ∼1″. Toward the prestellar clump we detected 10 compact structures (cores), with radii from 1200–4500 au and masses from 1.6–20 M
⊙. Half of these cores exhibit inverse P Cygni profiles in HCO+ and are subvirialized indicating that they are undergoing collapse. Toward the protostellar clump we detected a massive (119 M
⊙) central core, with a strong mass infall rate, and nine less massive cores, with masses from 1.7–27 M
⊙ and radii from 1000–4300 au. CH3CN rotational temperatures were derived for eight cores in the protostellar clump and three cores in the prestellar clump. Cores within the prestellar clump have smaller line widths and lower temperatures than cores within the protostellar clump. The fraction of total mass in cores to clump mass is smaller in the prestellar clump (∼6%) than in the protostellar clump (∼23%). We conclude that we are witnessing the evolution of the dense gas in globally collapsing MDCs; the prestellar clump illustrating the initial stage of fragmentation, harboring cores that are individually collapsing, and the protostellar clump reflecting a later stage in which a considerable fraction of the gas has been gravitationally focused into the central region.
Spatiotemporal Energy Partitioning in a Nonthermally Dominated Two-loop Solar Flare
Authors: Motorina Galina G. , Fleishman Gregory D. , Kontar Eduard P. 
Published: February 2020

Abstract
Solar flares show remarkable variety in the energy partitioning between thermal and nonthermal components. Those with a prominent nonthermal component but only a modest thermal one are particularly well suited for study of the direct effect of the nonthermal electrons on plasma heating. Here, we analyze such a well-observed, impulsive single-spike nonthermal event, a solar flare SOL2013-11-05T035054, where the plasma heating can be entirely attributed to the energy losses of these impulsively accelerated electrons. Evolution of the energy budget of thermal and nonthermal components during the flare is analyzed using X-ray, microwave, and EUV observations and three-dimensional modeling. The results suggest that (i) the flare geometry is consistent with a two-loop morphology and the magnetic energy is likely released due to interaction between these two loops; (ii) the released magnetic energy is converted to the nonthermal energy of accelerated electrons only, which is subsequently converted to the thermal energy of the plasma; (iii) the energy is partitioned in these two flaring loops in comparable amounts; (iv) one of these flaring loops remained relatively tenuous but rather hot, while the other remained relatively cool but denser than the first. Therefore, this solar flare demonstrates an extreme efficiency of conversion of the free magnetic energy to the nonthermal energy of particle acceleration and the flow of energy into two loops from the nonthermal component to the thermal one with negligible direct heating.
The Prospects of Observing Tidal Disruption Events with the Large Synoptic Survey Telescope
Authors: Bricman Katja , Gomboc Andreja 
Published: February 2020

Abstract
The upcoming Large Synoptic Survey Telescope (LSST) will observe 18,000 deg2 of the southern sky and is expected to discover thousands of transients every night due to its large coverage area and its observing strategy. In this work, we address the prospects for the LSST in discovering tidal disruption events (TDEs) and in probing the supermassive black hole (SMBH) mass distribution in the universe. We used the LSST simulation framework and defined TDE catalogs on 20 fields of 20.25 deg2 size. TDE properties were defined by randomly chosen impact factors and SMBH masses drawn from six different mass distributions. Observations of TDEs over 10 years of LSST operation were simulated by querying the simulated observing strategy database minion_1016. Based on the results of our simulations, we estimate that the LSST should discover between 35,000 and 80,000 TDEs in 10 years of operation, depending on the assumed SMBH mass distribution. We also find that probing the SMBH mass distribution with TDE observations will not be straightforward, due to the fact that TDEs caused by low-mass black holes (105
M
⊙) are expected to be less luminous and shorter than TDEs by heavier SMBHs (> 106
M
⊙), and therefore will mostly be missed by the irregular LSST cadence minion_1016.
Optical Variability of the TeV Blazar 1ES 0806+524 on Diverse Timescales
Authors: Pandey Ashwani , Gupta Alok C. , Kurtanidze Sofia O. , Wiita Paul J. , Damljanovic G. , Bachev R. , Zhang Jin , Kurtanidze O. M. , Darriba A. , Chigladze R. A. , Latev G. , Nikolashvili M. G. , Peneva S. , Semkov E. , Strigachev A. , Tiwari S. N. , Vince O. 
Published: February 2020

Abstract
We report the results of our optical (VRI) photometric observations of the TeV blazar 1ES 0806+524 on 153 nights during 2011–2019 using seven optical telescopes in Europe and Asia. We investigated the variability of the blazar on intraday as well as on long-term timescales. We examined 18 intraday light curves for flux and color variations using the most reliable power-enhanced F-test and the nested ANOVA test. Only on one night was a small, but significant, variation found, in both V-band and R-band light curves. The V−R color index was constant on every one of those nights. Flux density changes of around 80% were seen over the course of these eight years in multiple bands. We found a weighted mean optical spectral index of 0.639 ± 0.002 during our monitoring period by fitting a power law (

) in 23 optical (VRI) spectral energy distributions of 1ES 0806+524. We discuss different possible mechanisms responsible for blazar variability on diverse timescales.
Broad-line Region of the Quasar PG 2130+099 from a Two-year Reverberation Mapping Campaign with High Cadence
Authors: Hu Chen , Li Yan-Rong , Du Pu , Zhang Zhi-Xiang , Li Sha-Sha , Huang Ying-Ke , Lu Kai-Xing , Bai Jin-Ming , Ho Luis C. , Bian Wei-Hao , Brotherton Michael S. , Yuan Ye-Fei , Aceituno Jesús , Winkler Hartmut , Wang Jian-Min ,   (Seambh Collaboration)
Published: February 2020

Abstract
As one of the most interesting Seyfert 1 galaxies, PG 2130+099 has been the target of several reverberation mapping (RM) campaigns over the years. However, its measured broad Hβ line responses have been inconsistent, with time lags of ∼200 days, ∼25 days, and ∼10 days being reported for different epochs while its optical luminosity changed no more than 40%. To investigate this issue, we conducted a new RM-campaign with homogenous and high cadence (about ∼3 days) for two years during 2017–2019 to measure the kinematics and structure of the ionized gas. We successfully detected time lags of broad Hβ, He ii, He i, and Fe ii lines with respect to the varying 5100 Å continuum, revealing a stratified structure that is likely virialized with Keplerian kinematics in the first year of observations, but an inflow kinematics of the broad-line region from the second year. With a central black hole mass of

, PG 2130+099 has an accretion rate of

, where L
Edd is the Eddington luminosity and c is speed of light, implying that it is a super-Eddington accretor and likely possesses a slim, rather than thin, accretion disk. The fast changes of the ionization structures of the three broad lines remain puzzling.
Possible Formation Scenarios of ZTF J153932.16+502738.8—A Gravitational Source Close to the Peak of LISA’s Sensitivity
Authors: Lü Guoliang , Zhu Chunhua , Wang Zhaojun , Liu Helei , Li Lin , Xie Dian , Liu Jinzhong 
Published: February 2020

Abstract
ZTF J153932.16+502738.8 (ZTFJ1539) is an eclipsing double-white-dwarf system with an orbital period of 6.91 minutes, and a significant source for LISA detection of gravitational waves. However, the massive white dwarf (WD), with a mass of about 0.61 M
⊙, has a high effective temperature (48,900 K), and the lower-mass WD, with a mass of about 0.21 M
⊙, has a low effective temperature (<10,000 K). This discrepancy challenges the popular theory of binary evolution. We investigate the formation of ZTFJ1539 via nova and Algol scenarios. Assuming that the massive WD in ZTFJ1539 just experiences a thermonuclear runaway, the nova scenario can explain the effective temperatures of the two WDs in ZTFJ1539. However, in order to enlarge a semi-detached orbit of about 4–5 minutes to a detached orbit of about 7 minutes, the nova scenario needs a much higher kick velocity of about 200 km s−1 during nova eruption. The high kick velocity can result in a high eccentricity of about 0.2–0.6. The Algol scenario can also produce ZTFJ1539 if we take a high efficient parameter for ejecting the common envelope and enhance the mass-loss rate via stellar wind trigger by tidal effect.
De la mélodie à la pensée
Authors: de Gaudemar Martine 
Published: February 2020

La voix, qui met en œuvre des dispositions corporelles et des dispositifs sociohistoriques, exprime la condition humaine, indissolublement organique et symbolique. J’étudie d’abord l’échange primitif, expressif et musical : il montre qu’il faut un « accordage affectif » pour accéder à la communication. La voix suppose quelque chose « entre nous », elle nous vient toujours d’ailleurs. Puis je montre que la pensée se constitue à travers un processus de sémiotisation. La vocalité qui circule entre nous à travers des jeux de langage est la condition d’une puissance de comprendre ou « agency » intellectuelle.
L’art radiophonique ou les « architectures invisibles » de l’écoute : Helen Thorington et la poésie des connexions partielles
Authors: Indermuhle Christian 
Published: February 2020

Cet article explore comment l’artiste américaine Helen Thorington utilise la radiophonie pour créer un espace d’écoute démocratique et invisible, dans lequel les personnes qui écoutent peuvent entrer, « si elles le souhaitent ». Dans cet espace hybride où réel et fiction se font hanter réciproquement l’un par l’autre, l’expérience de l’écoute rend possible une nouvelle expérience politique de la littérature, dans laquelle chaque voix fait écho, dans sa décorporation matérialisée, au monde lui-même et trouve une fréquence pour se faire entendre.
L’écho de la voix
Authors: Motta Marco 
Published: February 2020

Dans cet essai, j’aimerais reprendre à mon compte les questions que se posent les éditeurs de ce numéro spécial sur la voix en les projetant dans un contexte particulier : le complexe rituel d’incorporation des esprits à Zanzibar, appelé uganga . J’aimerais m’arrêter ici sur la manière dont les gens s’approprient des esprits qui, dans un premier temps, leur sont étrangers, et apprennent ensuite à vivre avec eux sur le long terme, malgré les dissonances. Les humains deviennent alors les véhicules de voix qui se font l’écho les unes des autres. Mais plus que cela, la cohabitation quotidienne avec ces esprits, ces voix, devient un art de vivre. La question importante que pose la circulation des esprits parmi les humains est alors celle du rapport entre les voix des individus et celle de la communauté.
Citer et être cité
Authors: Fasula Pierre 
Published: February 2020

Une certaine lecture de Wittgenstein fait de « trouver sa voix dans les mots des autres » une question essentielle en philosophie du langage et de la subjectivité. Dans cet article, nous comprenons cette expression de manière littérale, avec le cas particulier de la citation : qu’est-ce que cela fait à une subjectivité que d’être citée ? Doit-on y voir une forme de réification de l’individu ? On défend que, dans certains cas, ce qui se trouve en jeu dans ce risque de réification, c’est en réalité la transformation d’un agent en spectateur de la conversation à son propos, et l’exploitation de ses propos transformés en bien.
Quand l’enfant n’a pas voix au chapitre. Étude sur le statut linguistique des enfants
Authors: Raïd Layla , Godart-Wendling Béatrice 
Published: February 2020

Une caractéristique de l’échange linguistique avec les enfants est l’usage, par les adultes, de la troisième personne pour parler des enfants en leur présence, sans les inclure dans les allocutaires. Nous montrons comment ce type d’échange a des formes et des conséquences morales et sociales différentes suivant l’âge de l’enfant. Nous abordons ces questions relatives au statut de l’enfant locuteur dans le cadre de la philosophie du langage ordinaire (Wittgenstein, Cavell), sur la base d’un corpus littéraire : la littérature française autobiographique du souvenir d’enfance (Jules Vallès, Violette Leduc, Jean-Paul Sartre, Nathalie Sarraute, Annie Ernaux).
Greffons !
Authors: Guignard Adrien 
Published: February 2020

Le propos constate la grosse fortune éditoriale et théorique du récit de maladies dans le contexte large des humanités médicales. Il acquiesce. L’interroge de manière critique, toutefois. Voici pourquoi une longue introduction s’essaie au développement du premier temps intitulé et nourri de copieux guillemets. On y glose, en effets, greffés, des éléments de la pensée de Brossat (pour le « biopolitique », issu de Foucault), d’Artières (pour l’historique du « clinique ») et de Bourdieu (pour « l’illusion »). Ces gloses effectuées font apparaître que des pensées peu favorables à une instrumentalisation promotrice d’une « fonction thérapeutique de la narrativité » convoquent admirablement la (grande) chose littéraire, alors que des conceptualisations pédagogiques contemporaines – proches des travaux revendiqués comme « sociologie clinique » – ne convoquent pas la littérature, mais en réclament des bénéfices « conscientisés ». La seconde partie du propos est plus empirique (voire « transitionnelle », ou presque). Appariée à la première en admettant qu’un des pouvoirs du récit de maladie consiste à « comprendre les compréhensions », elle propose des interprétations. Deux récits petitement littéraires (C. Valandrey et C. Desarzens) de greffes cardiaques sont convoqués. Les interprétations risquées laissent apparaître les logiques lucides, extralucides, policières organisatrices d’une opération réussie (mais très lourde) : répondre à la question de l’origine (du cœur transplanté). Une citation qui, elle, heureusement, n’y répond pas tirée de L’intrus (J.-L. Nancy) clôt l’article. Un post-scriptum ne le conclut pas.
Retraites : retour sur trente ans de débats et de réformes
Authors: Blanchet Didier 
Published: February 2020

Quatre réformes du système de retraite ont eu lieu en France depuis 1993. Par rapport à ce qui était attendu au début des années 1990, l’équilibre du système a été à peu près rétabli en jouant à parts à peu près égales entre hausse du taux d’effort des actifs – déjà engrangé –, décalage progressif de l’âge de la retraite et décrochement progressif du niveau de vie relatif des retraités. Mais l’équilibre ainsi atteint reste sensible aux hypothèses de croissance économique et à ce que sera la trajectoire effective du vieillissement démographique.