bluuebunny/crossref_metadata_2025_split huggingface dataset:
Glimpsing the Compositions of Sub-Neptune-Size Exoplanets
Authors: Rogers Leslie A. 
Published: January 2014

AbstractThe growing number of transiting planets with mass constraints opens the possibility of applying a statistical approach to learn about the underlying population of planet compositions. We focus on the intriguing transition between rocky exoplanets and planets with voluminous gas layers, and explore how the current census of sub-Neptune-size exoplanets constrains the maximum radii of rocky planets. We outline a hierarchical Bayesian model approach to infer the fraction of planets that are dense enough to be rocky (as a function of planet radius). A preliminary analysis of the current sample of planets with mass and radius constraints reveals that most planets larger than 1.9 R⊕ are too low density to be comprised of Fe and silicates alone.
Unveiling an exoplanetary Neptunian atmosphere through multiband transit photometry
Authors: Nascimbeni V. , Piotto G. , Pagano I. , Scandariato G. 
Published: January 2014

AbstractThe “effective” radius of a planet is a function of wavelength due to scattering and/or absorption processes, and we can exploit simultaneous multiband transit photometry to probe the atmospheric scale height and composition. We present new photometric data of the recently discovered “hot Uranus” GJ3470b, gathered with the LBC camera at LBT. Light curves of unprecedented accuracy (0.0012 mag in U and 0.00028 mag in a narrow band centered at 972 nm) allowed us to measure an increasingly larger planetary radius at shorter wavelengths, which we interpret as a signature of Rayleigh scattering by a large scale height atmosphere. Further follow-up observations to confirm this result and probe the presence of specific atomic and molecular species is ongoing.
The Shocking Variability Of Exoplanet Transits
Authors: Llama J. , Vidotto A. A. , Jardine M. , Wood K. , Fares R. 
Published: January 2014

AbstractAsymmetries in exoplanet transits are proving to be a useful tool for furthering our understanding of magnetic activity on both stars and planets outside our Solar System. Near-UV observations of the WASP- 12 system have revealed asymmetries in the timing of the transit when compared with the optical light curve. In this paper we review a number of reported asymmetries and present work simulating near-UV transits for the hot-Jupiter hosting star HD 189733.
A radiative-convective equilibrium model for young giant exoplanets: Application to β Pictoris b
Authors: Baudino Jean-Loup , Bézard Bruno , Boccaletti Anthony , Bonnefoy Mickael , Lagrange Anne-Marie 
Published: January 2014

AbstractWe present a radiative-convective equilibrium model for young giant exoplanets. Model predictions are compared with the existing photometric measurements of the planet β Pictoris b in the J, H, Ks, L', NB 4.05, M' bands. This model will be used to interpret future photometric and spectroscopic observations of exoplanets with SPHERE, mounted at the VLT with a first light expected mid-2014.
Additional Keplerian Signals in the HARPS data for Gliese 667C: Further Analysis
Authors: Gregory Philip C. , Lawler Samantha M. , Gladman Brett 
Published: January 2014

AbstractA re-analysis of Gliese 667C HARPS precision radial velocity data was carried out with a Bayesian multi-planet Kepler periodogram (from 0 to 7 planets) based on a fusion Markov chain Monte Carlo algorithm. The most probable number of signals detected is six with a Bayesian false alarm probability of 0.012. The residuals were shown to be consistent with white noise. The six signals detected include two previously reported with periods of 7.198 (b) and 28.14 (c) days, plus additional periods of 30.82, 38.82, 53.22, and 91.3 days. The existence of these Keplerian-like signals suggest the possibility of additional planets in the habitable zone of Gl 667C although some of the signals could be artifacts arising from the sampling or stellar surface activity. N-body orbital integrations are being undertaken to determine which of these signals are consistent with a stable planetary system. Preliminary results demonstrate that four of the signals, with periods of 7.2, 28.1, 38.8, & 91 d, are consistent with a stable 4 planet system on time scales of 107 yr. The M sin i values are ~5.5, 4.4, 1.9, and 4.7 M⊕, respectively.
Cosmic Rays, UV Photons, and Haze Formation in the Upper Atmospheres of Hot Jupiters
Authors: Rimmer Paul B. , Walsh Catherine , Helling Christiane 
Published: January 2014

AbstractCosmic ray ionization has been found to be a dominant mechanism for the formation of ions in dense interstellar environments. Cosmic rays are further known to initiate the highly efficient ion-neutral chemistry within star forming regions. In this talk we explore the effect of both cosmic rays and UV photons on a model hot Jupiter atmosphere using a non-equlibrium chemical network that combines reactions from the UMIST Database for Astrochemistry, the KIDA database for interstellar and protoplanetary environments and three-body and combustion reactions from the NIST database and from various irradiated gas planet networks. The physical parameters for our model atmosphere are based on HD 189733 b (Effective Temperature of 1000 K, log g = 3.3, solar metallicity, at a distance 0.03 AU from a K dwarf). The active UV photochemistry high in our model hot Jupiter atmosphere tends to destroy these hydrocarbons, but on a time-scale sufficiently slow that PAH formation could already have taken place. In most cases, carbon-bearing species formed by cosmic rays are destroyed by UV photons (e.g. C2H2, C2H4, HC3N). Conversely, carbon-bearing species enhanced by an active photochemistry are depleted when cosmic ray ionization is significant (e.g. CN, HCN and CH4). Ammonia is an interesting exception to this trend, enhanced both by an active photochemistry and a high cosmic ray ionization rate.
Next Generation Transit Survey (NGTS)
Authors: Wheatley Peter J. , Pollacco Don L. , Queloz Didier , Rauer Heike , Watson Christopher A. , West Richard G. , Chazelas Bruno , Louden Tom M. , Bannister Nigel , Bento Joao , Burleigh Matthew , Cabrera Juan , Eigmüller Philipp , Erikson Anders , Genolet Ludovic , Goad Michael , Grange Andrew , Jordán Andrés , Lawrie Katherine , McCormac James , Neveu Marion , Walker Simon 
Published: January 2014

AbstractThe Next Generation Transit Survey (NGTS) is a new ground-based survey for transiting exoplanets. Our primary goal is to find the first statistically-significant sample of Neptunes and super-Earths that are bright enough for radial velocity confirmation. By measuring precise masses and radii we will constrain the bulk composition and internal structure of planets that span the transition between the gas giants and terrestrial planets. Our brightest exoplanets will also be suitable for atmospheric characterisation with large facilities such as the VLT, JWST and the E-ELT. NGTS construction began in June 2013, and the survey is due to commence in 2014.
Signposts of Multiple Planets in Debris Disks
Authors: Su Kate Y. L. , Rieke G. H. 
Published: January 2014

AbstractWe review the nearby debris disk structures revealed by multi-wavelength images from Spitzer and Herschel, and complemented with detailed spectral energy distribution modeling. Similar to the definition of habitable zones around stars, debris disk structures should be identified and characterized in terms of dust temperatures rather than physical distances so that the heating power of different spectral type of stars is taken into account and common features in disks can be discussed and compared directly. Common features, such as warm (~150 K) dust belts near the water-ice line and cold (~50 K) Kuiper-belt analogs, give rise to our emerging understanding of the levels of order in debris disk structures and illuminate various processes about the formation and evolution of exoplanetary systems. In light of the disk structures in the debris disk twins (Vega and Fomalhaut), and the current limits on the masses of planetary objects, we suggest that the large gap between the warm and cold dust belts is the best signpost for multiple (low-mass) planets beyond the water-ice line.
Locating the Dust in A Star Debris Discs
Authors: Booth Mark , Kennedy Grant , Sibthorpe Bruce , Matthews Brenda C. , Wyatt Mark C. , Duchêne Gaspard , Kavelaars J. J. , Rodriguez David , Greaves Jane S. , Koning Alice , Vican Laura , Rieke George H. , Su Kate Y. L. , Moro-Martín Amaya , Kalas Paul 
Published: January 2014

AbstractUsing photometry at just two wavelengths it is possible to fit a blackbody to the spectrum of infrared excess that is the signature of a debris disc. From this the location of the dust can be inferred. However, it is well known that dust in debris discs is not a perfect blackbody. By resolving debris discs we can find the actual location of the dust and compare this to that inferred from the blackbody fit. Using the Herschel Space Observatory we resolved many systems as part of the DEBRIS survey. Here we discuss a sample of 9 discs surrounding A stars and find that the discs are actually located between 1 and 2.5 times further from their star than predicted by blackbody fits to the spectral energy distribution (SED). The variation in this ratio is due to differences in stellar luminosities, location of the dust, size distribution and composition of the dust.
Unraveling the Mystery of Exozodiacal Dust
Authors: Ertel S. , Augereau J.-C. , Thébault P. , Absil O. , Bonsor A. , Defrère D. , Kral Q. , Le Bouquin J.-B. , Lebreton J. , Coudé du Foresto V. 
Published: January 2014

AbstractExozodiacal dust clouds are thought to be the extrasolar analogs of the Solar System's zodiacal dust. Studying these systems provides insights in the architecture of the innermost regions of planetary systems, including the Habitable Zone. Furthermore, the mere presence of the dust may result in major obstacles for direct imaging of earth-like planets. Our EXOZODI project aims to detect and study exozodiacal dust and to explain its origin. We are carrying out the first large, near-infrared interferometric survey in the northern (CHARA/FLUOR) and southern (VLTI/PIONIER) hemispheres. Preliminary results suggest a detection rate of up to 30% around A to K type stars and interesting trends with spectral type and age. We focus here on presenting the observational work carried out by our team.
A Modal Analysis of the Irradiation Instability
Authors: Fung Jeffrey , Artymowicz Pawel 
Published: January 2014

AbstractThe irradiation instability is a disk instability caused by the radiation pressure cast by a central source onto an optically thick disk. The criterion for this instability depends on a sharp transition from an optically thin inner disk to an optically thick outer disk. The quickly diminishing radiation pressure in this transition region creates a radially compressing effect, which is in many ways similar to the effects of self-gravity. In this modal analysis, we demonstrate that a disk marginally stable to irradiation can develop global modes, with growth rates being of order the dynamical timescale of the disk. The non-linear evolution of the our model shows the formation of vortices near the transition region and spiral structures propagating into the optically thick region. Consequently the scale-height of our disk's inner edge becomes time-variable and can likely be observed as a variation in its infrared flux.
Formation and evolution of an active region filament
Authors: Kuckein Christoph , Centeno Rebeca , Pillet Valentín Martínez 
Published: January 2014

AbstractSeveral scenarios explaining how filaments are formed can be found in literature. In this paper, we analyzed the observations of an active region filament and critically evaluated the observed properties in the context of current filament formation models. This study is based on multi-height spectropolarimetric observations. The inferred vector magnetic field has been extrapolated starting either from the photosphere or from the chromosphere. The line-of-sight motions of the filament, which was located near disk center, have been analyzed inferring the Doppler velocities. We conclude that a part of the magnetic structure emerged from below the photosphere.
Non-LTE Modeling and Observations of Oscillating Prominences
Authors: Zapiór M. , Heinzel P. , Oliver R. , Ballester J. L. , Kotrč P. 
Published: January 2014

AbstractProminence oscillations have been mostly detected using Doppler velocity, although there are also claimed detections by means of the periodic variations of half-width or line intensity. Our main aim here is to explore the relationship between spectral indicators such as Doppler shift, line intensity and line half-width and the linear perturbations excited in a simple prominence model.
The inference of the magnetic field vector in prominences
Authors: Lites Bruce W. 
Published: January 2014

AbstractProminences owe their existence to the presence of magnetic fields in the solar corona. The magnetic field determines their geometry and is crucial to their stability, energetics, and dynamics. This review summarizes techniques for measurement of the magnetic field vector in prominences. New techniques for inversions of full Stokes spectro-polarimetry, incorporating both the Zeeman and Hanle mechanisms for generation and modification of polarization, are now at the forefront. Also reviewed are measurements of the magnetic fields in the photosphere below prominences, and how they may be used to infer the field geometry in and surrounding the prominence itself.
Explaining the Hemispheric Pattern of Filament Chirality
Authors: Mackay Duncan H. , Yeates Anthony R. 
Published: January 2014

AbstractSolar filaments are known to exhibit a hemispheric pattern in their chirality, where dextral/sinistral filaments dominate in the northern/southern hemisphere. We show that this pattern may be explained through data driven 3D global magnetic field simulations of the Sun's large-scale magnetic field. Through a detailed comparison with 109 filaments over a 6 month period, the model correctly reproduces the filament chirality and helicity with a 96% agreement. The data driven simulation is extended to run over a full solar cycle, where predictions are made for the spatial and temporal dependence of the hemispheric pattern over the solar cycle.
On the dynamics of eruptive prominences
Authors: Balmaceda Laura A. , Cremades Hebe , Stenborg Guillermo , Francile Carlos , Di Lorenzo Leonardo , López Fernando 
Published: January 2014

AbstractTo contribute to the understanding of the physical mechanisms at work during the initial phase and early evolution of erupting prominences, we analyze combined observations from ground-based and space-borne instruments. We present two case studies, which occurred at two different phases of the solar cycle, namely on March 2, 2002 and on April 16, 2012. In particular, we show the results of a morphological and kinematical analysis and interpret them in terms of available theoretical models.
Complex Evolution of Coronal Mass Ejections in the Inner Heliosphere as Revealed by Numerical Simulations and STEREO Observations: A Review
Authors: Lugaz Noé , Farrugia Charles J. , Al-Haddad Nada 
Published: January 2014

AbstractThe transit of coronal mass ejections (CMEs) from the Sun to 1 AU lasts on average one to five days. As they propagate, CMEs interact with the solar wind and preceding eruptions, which modify their properties. In the past ten years, the evolution of CMEs in the inner heliosphere has been investigated with the help of numerical simulations, through the analysis of remote-sensing heliospheric observations, especially with the SECCHI suite onboard STEREO, and through the analysis of multi-spacecraft in situ measurements. Most studies have focused on understanding the characteristics of the magnetic flux rope thought to form the core of the CME. Here, we first review recent work related to CME propagation in the heliosphere, which point towards the need to develop more complex models to analyze CME observations. In the second part of this article, we review some recent studies of CME-CME interaction, which also illustrate the complexity of phenomena occurring in the inner heliosphere.
Observations of stellar coronae and prominences
Authors: Hussain Gaitee A. J. 
Published: January 2014

AbstractX-ray and EUV observations of young cool stars have shown that their coronae are extremely pressured environments with temperatures and densities that are up to two orders of magnitudes larger than those observed in the solar corona. At the same time rapidly transiting absorption features in optical and UV spectra reveal the presence of large cool, prominence-type complexes that can extend several stellar radii. I will give an overview of our current understanding of coronal structures in cool stars from multi-wavelength observations, detailing their properties and apparent dependence on spectral type. I will also outline future prospects in this field, particularly from observations of stellar coronal environments at radio and sub-mm wavelengths.
Scientific Programmes with India's National Large Solar Telescope and their contribution to Prominence Research
Authors: Hasan S. S. 
Published: January 2014

AbstractThe primary objective of the 2-m National Large Solar Telescope (NLST) is to study the solar atmosphere with high spatial and spectral resolution. With an innovative optical design, NLST is an on-axis Gregorian telescope with a low number of optical elements and a high throughput. In addition, it is equipped with a high order adaptive optics system to produce close to diffraction limited performance.NLST will address a large number of scientific questions with a focus on high resolution observations. With NLST, high spatial resolution observations of prominences will be possible in multiple spectral lines. Studies of magnetic fields, filament eruptions as a whole, and the dynamics of filaments on fine scales using high resolution observations will be some of the major areas of focus.
Prominence Science with ATST Instrumentation
Authors: Rimmele Thomas , Berger Thomas , Casini Roberto , Elmore David , Kuhn Jeff , Lin Haosheng , Schmidt Wolfgang , Wöger Friedrich 
Published: January 2014

AbstractThe 4m Advance Technology Solar Telescope (ATST) is under construction on Maui, HI. With its unprecedented resolution and photon collecting power ATST will be an ideal tool for studying prominences and filaments and their role in producing Coronal Mass Ejections that drive Space Weather. The ATST facility will provide a set of first light instruments that enable imaging and spectroscopy of the dynamic filament and prominence structure at 8 times the resolution of Hinode. Polarimeters allow high precision chromospheric and coronal magnetometry at visible and infrared (IR) wavelengths. This paper summarizes the capabilities of the ATST first-light instrumentation with focus on prominence and filament science.
Instrument concepts for the observation of prominences with future ground-based telescopes
Authors: Ariste A. López 
Published: January 2014

AbstractThe observation of prominences with ground-based telescopes suffers from poor image quality due to atmospheric turbulence when compared with space-borne instruments which, for solar observations, are of similar apertures. To make ground-based instruments competitive, they should rely on spectropolarimetry and the measurement of prominence magnetic fields, a task which no foreseable space instrument will perform. But spectropolarimetry alone does not suffice, and we argue that future instrumentation should combine it with imaging in a large field of view and good temporal resolution. We place numbers on those requirements and give examples of instrumental accomplishments already at work today that forecast a new generation of instruments for the observation of prominences from ground-based telescopes.
Coronal Loop Mapping to Infer the Best Magnetic Field Models for Active Region Prominences
Authors: Gary G. Allen , Hu Qiang , Lee Jong Kwan 
Published: January 2014

AbstractThis article comments on the results of a new, rapid, and flexible manual method to map on-disk individual coronal loops of a two-dimensional EUV image into the three-dimensional coronal loops. The method by Gary, Hu, and Lee (2013) employs cubic Bézier splines to map coronal loops using only four free parameters per loop. A set of 2D splines for coronal loops is transformed to the best 3D pseudo-magnetic field lines for a particular coronal model. The results restrict the magnetic field models derived from extrapolations of magnetograms to those admissible and inadmissible via a fitness parameter. This method uses the minimization of the misalignment angles between the magnetic field model and the best set of 3D field lines that match a set of closed coronal loops. We comment on the implication of the fitness parameter in connection with the magnetic free energy and comment on extensions of our earlier work by considering the issues of employing open coronal loops or employing partial coronal loop.
Mapping prominence plasma parameters from eclipse observations
Authors: Jejčič Sonja , Heinzel Petr , Zapiór Maciej , Druckmüller Miloslav , Gunár Stanislav , Kotrč Pavel 
Published: January 2014

AbstractUsing the eclipse observations, we construct the maps of quiescent prominence temperatures, electron densities, pressures and geometrical thicknesses. For this we use the RGB signal of prominence visible-light emission detected during the total solar eclipse on August 1, 2008 in Mongolia, and quasi-simultaneous Hα spectra taken at Ondřejov observatory. The method of disentangling the electron density and effective geometrical thickness was described by Jejčič & Heinzel (2009) and is used here for the first time to analyse the spatial variations of various prominence parameters.
Signatures of magnetic reconnection during the evolutionary phases of a prominence eruption and associated X1.8 flare
Authors: Joshi Bhuwan , Kushwaha Upendra , Cho KyungSuk , Veronig Astrid 
Published: January 2014

AbstractIn this paper, we present RHESSI and TRACE observations of multiple flare activity that occurred in the active region NOAA 10656 on 2004 August 18. Out of four successive flares, there were three events of class-C while the final event was a major X1.8 solar eruptive flare. During localized C-class flares, the filament undergoes slow yet crucial morphological evolution. The filament eruption is accompanied with an X1.8 flare during which multiple HXR bursts are observed up to 100–300 keV energies. From the location, timing, strength, and spectrum of HXR emission, we conclude that the prominence eruption is driven by the distinct events of magnetic reconnection occurring in the current sheet below the erupting prominence. These multi-wavelength observations also provide evidence for tether-cutting reconnection as the triggering mechanism for filament eruption and associated X-class flare.