bluuebunny/crossref_metadata_2025_split huggingface dataset:
High Contrast Imaging of an Exoplanet with the Magellan VisAO Camera
Authors: Males Jared R. , Close Laird M. , Morzinski Katie M. , Kopon Derek , Puglisi Alfio , Gasho Victor , Follette Kate , Esposito Simone , Riccardi Armando , Pinna Enrico , Xompero Marco , Briguglio Runa , Arcidiacono Carmelo , Hinz Phil M. , Uomoto Alan , Hare Tyson , Quiros-Pacheco Fernando , Argomedo Javier , Busoni Lorenzo , Rodigas T.J. , Wu Ya-Lin 
Published: January 2014

AbstractThe Magellan Adaptive Optics (MagAO) system saw first light in November 2012 at Las Campanas Observatory (LCO) on the 6.5m Clay telescope. Here we present an introduction to MagAO's visible wavelength diffraction limited imager, VisAO. VisAO delivers Strehl ratios greater than 30% from 0.62 microns (r') through 1 micron, where Strehl is even higher, and achieved resolutions as small as 20 milli-arcseconds. We took advantage of the excellent performance of MagAO/VisAO to conduct high contrast observations of an exoplanet in the optical. With VisAO, we are, for the first time, able to begin characterizing exoplanet atmospheres in the optical from the ground.
Solving for the Orbital Elements of Binary Systems using MCMC Simulations.
Authors: Mede Kyle , Brandt Timothy D. 
Published: January 2014

AbstractRecent simulation and observational data have been used to investigate the ability of Kozai oscillations to explain the formation of “hot Jupiter” planetary systems. One of the first exoplanets discovered, τ Boo Ab, orbits a star with a binary companion, making it an excellent testbed for this scenario. We have written a three-dimensional Markov Chain Monte Carlo (MCMC) simulator to constrain the orbit of the distant stellar companion τ Boo B, and are currently deriving orbital parameters and confidence intervals. These orbital parameters will confirm or reject Kozai oscillations as a plausible formation mechanism for τ Boo Ab.
Polarimetry with the Gemini Planet Imager: Instrument Characterization and Future Science
Authors: Millar-Blanchaer Max , Wiktorowicz Sloane J. , Perrin Marshall D. , Graham James R. , Thomas Sandrine J. , Dillon Daren , Fitzgerald Michael P. , Maire Jérome , Macintosh Bruce , Goodsell Stephen J. 
Published: January 2014

AbstractThe Gemini Planet Imager (GPI) is a high contrast coronagraph designed to directly image exoplanets and circumstellar disks. GPI includes a polarimetry mode designed to characterize dust grains and enhance the contrast of scattered, polarized light by a factor of 100. Reflections and birefringence of optics within the optical train induce a polarization signature that needs to be measured a priori and calibrated out during data reduction. Here we report on the results of an extensive laboratory characterization campaign of the polarimetry mode. The linear instrumental polarization has been measured in 4 GPI passbands and found to be between 3.5 ± 0.3 % at 1.0 micron and 1.1 ± 0.3 % at 2.0 microns. Modulation efficiency has been measured to be 94% at 1.0 micron increasing to 97% at 2.0 microns. Stability has been shown to better than 0.6% over timescales of ~ 3 months and over cool down cycles. The tests show that GPI passes all polarimetry design requirements and should be able to measure circumstellar disk linear polarization to 1% accuracy.
LEECH: A 100 Night Exoplanet Imaging Survey at the LBT
Authors: Skemer Andrew , Apai Daniel , Bailey Vanessa , Biller Beth , Bonnefoy Mickael , Brandner Wolfgang , Buenzli Esther , Close Laird , Crepp Justin , Defrere Denis , Desidera Silvano , Eisner Josh , Esposito Simone , Fortney Jonathan , Henning Thomas , Hinz Phil , Hofmann Karl-Heinz , Leisenring Jarron , Males Jared , Millan-Gabet Rafael , Morzinski Katie , Oza Apurva , Pascucci Ilaria , Patience Jenny , Rieke George , Schertl Dieter , Schlieder Joshua , Skrutskie Mike , Su Kate , Weigelt Gerd , Woodward Charles E. , Zimmerman Neil 
Published: January 2014

AbstractIn February 2013, the LEECH (LBTI Exozodi Exoplanet Common Hunt) survey began its 100-night campaign from the Large Binocular Telescope atop Mount Graham in Arizona. LEECH neatly complements other high-contrast planet imaging efforts by observing stars in L' band (3.8 microns) as opposed to the shorter wavelength near-infrared bands (1–2.3 microns). This part of the spectrum offers deeper mass sensitivity for intermediate age (several hundred Myr-old) systems, since their Jovian-mass planets radiate predominantly in the mid-infrared. In this proceedings, we present the science goals for LEECH and a preliminary contrast curve from some early data.
Resolved Scattered Light Images of the Edge-On Protoplanetary Disk ESO Hα 569
Authors: Wolff S. , Perrin M. , Stapelfeldt K. , Duchêne G. , Krist J. , Ménard F. , Padgett D. , Pinte C. 
Published: January 2014

AbstractWe present detailed models of the edge-on protoplanetary disk ESO Hα 569 (SSTgbs J111110.7-764157) from resolved scattered light images from HST and a complete spectral energy distribution. Data was obtained as part of an HST campaign to catalogue edge-on disks around young stars in nearby star forming regions (HST program 12514, PI: Karl Stapelfeldt). We confirm that this object is an optically thick edge-on disk around a young star with an outer radius of 125 AU. Using full radiative transfer models, we probe the distribution of dust grains and overall shape of the disk (inclination, scale height, dust mass, maximum particle size, inner radius, flaring exponent and surface/volume density exponent).
IRDIS, the dual-band imager camera of SPHERE: testing the performances in laboratory
Authors: Zurlo A. , Vigan A. , Moutou C. , Mesa D. , Gratton R. , Langlois M. , Beuzit J.-L. , Costille A. , Desidera S. , Dolhen K. , Gry C. , Madec F. , Le Mignant D. , Mouillet D. , Sauvage J.-F. 
Published: January 2014

AbstractNext year the second generation instrument SPHERE will begin science operations at the Very Large Telecope (ESO). This instrument will be dedicated to the search for exoplanets through the direct imaging techniques, with the new generation extreme adaptive optics. In this poster, we present the performances of one of the focal instruments, the Infra-Red Dual-beam Imaging and Spectroscopy (IRDIS). All the results have been obtained with tests in laboratory, simulating the observing conditions in Paranal. We tested several configurations using the sub-system Integral Field Spectrograph (IFS) in parallel and simulating long coronographic exposures on a star, calibrating instrumental ghosts, checking the performance of the adaptive optics system and reducing data with the consortium pipeline. The contrast one can reach with IRDIS is of the order of 10−6 at 0.5 arcsec separation from the central star.
Planet formation in action: resolved gas and dust images of a transitional disk and its cavity
Authors: van der Marel Nienke , van Dishoeck Ewine F. , Bruderer Simon , Birnstiel Til , Pinilla Paola , Dullemond Cornelis P. , van Kempen Tim A. , Schmalzl Markus , Brown Joanna M. , Herczeg Gregory J. , Mathews Geoffrey S. , Geers Vincent 
Published: January 2014

AbstractPlanet formation and clearing of protoplanetary disks is one of the long standing problems in disk evolution theory. The best test of clearing scenarios is observing systems that are most likely to be actively forming planets: the transitional disks with large inner dust cavities. We present the first results of our ALMA (Atacama Large Millimeter/submillimeter Array) Cycle 0 program using Band 9, imaging the Herbig Ae star Oph IRS 48 in CO 6−5 and the submillimeter continuum in the extended configuration. The resulting ~0.2″ spatial resolution completely resolves the cavity of this disk in the gas and the dust. The gas cavity of IRS 48 is half as large as the dust cavity, ruling out grain growth and photoevaporation as the primary cause of the truncation. On the other hand, the continuum emission reveals an unexpected large azimuthal asymmetry and steep edges in the dust distribution along the ring, suggestive of dust trapping. We will discuss the implications of the combined gas and dust distribution for planet formation at a very early stage. This is one of the first transition disks with spatially resolved gas inside the cavity, demonstrating the superb capabilities of the Band 9 receivers.
Zooming in on the Formation of Protoplanetary Disks
Authors: Nordlund Åke , Haugbølle Troels , Küffmeier Michael , Padoan Paolo , Vasileiades Aris 
Published: January 2014

AbstractWe use the adaptive mesh refinement code RAMSES to model the formation of protoplanetary disks in realistic star formation environments. The resolution scales over up to 29 powers of two (~ 9 orders of magnitude) covering a range from outer scales of 40 pc to inner scales of 0.015 AU. The accretion rate from a 1.5 solar mass envelope peaks near 10−4 M⊙ about 6 kyr after sink particle formation and then decays approximately exponentially, reaching 10−6 M⊙ in 100 kyr. The models suggest universal scalings of physical properties with radius during the main accretion phase, with kinetic and / or magnetic energy in approximate balance with gravitational energy. Efficient accretion is made possible by the braking action of the magnetic field, which nevertheless allows a near-Keplerian disk to grow to a 100 AU size. The magnetic field strength ranges from more than 10 G at 0.1 AU to less than 1 mG at 100 AU, and drives a time dependent bipolar outflow, with a collimated jet and a broader disk wind.
Simultaneous Visible and Near-Infrared Variability of Classical T Tauri Stars
Authors: Aimi Yukako , Fukagawa Misato , Yasuda Tomonori , Yamashita Takuya , Kawabata Kouji , Uemura Makoto , Arai Akira , Sasada Mahito , Ohsugi Takashi , Yoshida Michitoshi , Shibai Hiroshi 
Published: January 2014

AbstractTemporal structural changes of protoplanetary disks surrounding T Tauri stars (TTSs) can cause magnitude variations of TTSs. On the other hand, variability is also expected due to cool spots and/or hot spots on the surface of the star, thus it is important to distinguish the causes of the observed variability. Our sample consists of 23 TTSs (22 classical T Tauri stars, 1 weak-lined T Tauri star) and 4 Herbig Ae/Be stars. The observations were performed over a period of about 3 months in the V, J, and KS band, simultaneously. We detected variability for all stars in the three bands (>0.05 mag in V, >0.09 mag in J, >0.09 mag in KS). Color-magnitude relations obtained between V, J, and KS bands suggest that stellar spots are not the only cause of variability for most of our targets. In addition, the data implies that six stellar systems contain larger grains than in the interstellar medium if the variability is only caused by extinction due to circumstellar matter.
Large-scale planetesimal formation by streaming instability
Authors: Yang Chao-Chin , Johansen Anders 
Published: January 2014

AbstractIn current theory of planet formation, streaming instability is one of the most promising mechanisms to overcome the meter-barrier in the course of core accretion. Almost all previous works, however, were focused on a local region of protoplanetary disks with a limited size of about 0.2 gas scale heights. Only one radial filamentary particle concentration was seen in these studies. To address this, we conduct the largest-scale simulations of this kind to date, up to 0.8 gas scale heights both horizontally and vertically. We demonstrate that streaming instability remains robust on large scale and multiple radial particle concentrations exist in large enough boxes. This result may be important in characterising the feeding zone of planetesimal formation.
Planet formation in evolving protoplanetary discs
Authors: Alexander Richard 
Published: January 2014

AbstractI attempt to summarize our knowledge of planet formation in evolving protoplanetary discs. I first review the physics of disc evolution and dispersal. For most of the disc lifetime evolution is driven by accretion and photoevaporation, and I discuss how the interplay between these processes shapes protoplanetary discs. I also discuss the observations that we use to test these models, and the major uncertainties that remain. I will then move on to consider planet formation and migration in evolving discs, and discuss how observations of both discs and planets can be used to inform our understanding of protoplanetary disc evolution.
The multiple spirals in the disk of HD100546
Authors: Boccaletti A. , Lagrange A.-M. , Pantin E. , Augereau J.-C. , Quanz S. P. , Meheut H. 
Published: January 2014

AbstractWe report the detection of multi-armed spirals in the environment of HD 100546 using NICI at Gemini South in the Ks band. These data feature a better angular resolution and higher contrast than previous HST images, which allows to resolve the former known spiral into a multiple pattern. An analytic model with a gravitational perturber is used to fit the spiral pattern. We derived limit of detections which set constraints on the discovered forming planet.
Planetary Systems Dynamics Eccentric patterns in debris disks & Planetary migration in binary systems
Authors: Faramaz V. , Beust H. , Augereau J.-C. , Bonsor A. , Thébault P. , Wu Y. , Marshall J. P. , del Burgo C. , Ertel S. , Eiroa C. , Montesinos B. , Mora A. ,   the DUNES team
Published: January 2014

AbstractWe present some highlights of two ongoing investigations that deal with the dynamics of planetary systems. Firstly, until recently, observed eccentric patterns in debris disks were found in young systems. However recent observations of Gyr-old eccentric debris disks leads to question the survival timescale of this type of asymmetry. One such disk was recently observed in the far-IR by the Herschel Space Observatory around ζ2 Reticuli. Secondly, as a binary companion orbits a circumprimary disk, it creates regions where planet formation is strongly handicapped. However, some planets were detected in this zone in tight binary systems (γ Cep, HD 196885). We aim to determine whether a binary companion can affect migration such that planets are brought in these regions and focus in particular on the planetesimal-driven migration mechanism.
Chasing disk dispersal indicators: the origin of the [OI] low-velocity components from young stars
Authors: Rigliaco Elisabetta , Pascucci Ilaria , Gorti Uma , Edwards Suzan , Holenbach David 
Published: January 2014

AbstractUnderstanding how a disk surrounding a young star evolves and disperses is crucial in order to understand the subsequent planet formation. In this proceeding, we summarize the results reported by Rigliaco et al. (2013) on the origin of the [OI] low-velocity component as a possible disk dispersal indicator.
β Pictoris b Orbital Properties
Authors: Lagrange Anne-Marie , Gilardy Hugo , Beust Herve , Chauvin Gael , Rameau Julien , Boccaletti Anthony , Girard Julien , Bonnefoy Mickael 
Published: January 2014

AbstractWe present the results of the astrometric monitoring of βPictoris b, the closest exoplanet imaged so far, using all VLT/NaCo data we obtained so far.
On Lifetimes of Dusty Debris Disks around A-type Stars
Authors: de la Reza Ramiro , Chavero Carolina 
Published: January 2014

AbstractUsing a collection of 40 debris disks (DD) around dwarf A-type stars (from which 17 are spatially resolved) having well determined stellar ages (Vican 2012), we found that for a collisional self-stirring model of flux distributions (Kenyon & Bromley, 2008, 2010) dusty DD occupy for a large part the terminal age positions corresponding the end of the MS phase. This situation does not necessarily mean that the dust generation in these DD is finished at this stage. Dusty DD can continue their lives in the next Post-MS stages, as is the case of the recent first resolved dusty DD with planets around the K-type subgiant star κ CrB. This star is considered a “retired” A star (Bonsor et al. 2013). In order to explain the apparent lack of dusty DD in the giant phase, we propose here that this could be due, in part, to a dilution of any planetesimal belt existing around these stars, with the corresponding diminishing of collisions and subsequent dust generation. This dilution is provoked by the dynamical expansion of this belt produced by the important stellar mass loss during the RGB phase. This scenario is being studied by means of numerical simulations by de la Reza, Roig & Chavero 2013 (in preparation).
Herschel Observations of the HR 8799 Disk
Authors: Matthews Brenda C. , Kennedy Grant , Sibthorpe Bruce , Booth Mark , Broekhoven-Fiene Hannah , Wyatt Mark , Macintosh Bruce , Marois Christian 
Published: January 2014

AbstractThe HR 8799 four-planet host is known to host a multi-component disk from Spitzer observations. We have obtained Herschel† observations of the disk which provide increased sensitivity and resolution of its outer components: the planetesimal belt and halo. We find that the two components cannot be discerned from the spectral energy distribution alone, but require resolved images to independently identify them. In the resolved images, the halo stands out for its steep radial profile and large radial extent to 2000 AU, a factor of two larger than was estimated from Spitzer data.
Abundances in Stars with Debris Disks
Authors: Ritchey Adam M. , Gonzalez Guillermo , Stone Myra , Wallerstein George 
Published: January 2014

AbstractWe present preliminary results of a detailed chemical abundance analysis for a sample of solar-type stars known to exhibit excess infrared emission associated with dusty debris disks. Our sample of 28 stars was selected based on results from the Formation and Evolution of Planetary Systems (FEPS) Spitzer Legacy Program, for the purpose of investigating whether the stellar atmospheres have been polluted with planetary material, which could indicate that the metallicity enhancement in stars with planets is due to metal-rich infall in the later stages of star and planet formation. The preliminary results presented here consist of precise abundances for 15 elements (C, O, Na, Mg, Al, Si, S, Ca, Sc, Ti, V, Cr, Fe, Co, and Ni) for half of the stars in our sample. We find that none of the stars investigated so far exhibit the expected trend of increasing elemental abundance with increasing condensation temperature, which would result from the stars having accreted planetary debris. Rather, the slopes of linear least-squares fits to the abundance data are either negative or consistent with zero. In both cases, our results may indicate that, like the Sun, the debris disk host stars are deficient in refractory elements, a possible signature of terrestrial and/or gas giant planet formation.
Swansong Biospheres: The biosignatures of inhabited earth-like planets nearing the end of their habitable lifetimes
Authors: O'Malley-James Jack T. , Greaves Jane S. , Raven John A. , Cockell Charles S. 
Published: January 2014

AbstractThe biosignatures of life on Earth are not fixed, but change with time as environmental conditions change and life living within those environments adapts to the new conditions. A latitude-based climate model, incorporating orbital parameter variations, was used to simulate conditions on the far-future Earth as the Sun enters the late main sequence. Over time, conditions increasingly favour a unicellular microbial biosphere, which can persist for a maximum of 2.8 Gyr from present. The biosignature changes associated with the likely biosphere changes are evaluated using a biosphere-atmosphere gas exchange model and their detectability is discussed. As future Earth-like exoplanet discoveries could be habitable planets nearing the end of their habitable lifetimes, this helps inform the search for the signatures of life beyond Earth
A Hot Jupiter in a Nearly Polar Orbit
Authors: Addison Brett C. , Tinney Chris G. , Wright Duncan J. , Bayliss Daniel , Zhou George , Hartman Joel D. , Bakos Gáspár Á. , Schmidt Brian 
Published: January 2014

AbstractWe measured the spin-orbit misalignment for WASP-79b, a transiting hot Jupiter from the WASP survey. Using the Rossiter-McLaughlin effect during the transit event, we determined the sky-projected obliquity to be λ = −106+10−8○. This result indicates that the planet is in a nearly polar orbit.
Plasma properties in eruptive prominences
Authors: Labrosse Nicolas 
Published: January 2014

AbstractProminence eruptions are one of the most spectacular manifestations of our Sun's activity. Yet there is still some mystery surrounding their relevant physical conditions. What are their plasma parameters? How different are they from those of quiescent prominences? How do they relate to those within coronal mass ejections? We briefly review some recent results in non-LTE radiative transfer modelling which contribute to our knowledge of the plasma properties in eruptive prominences. We discuss in particular how these results, combined with observational data analysis, can help us in determining the plasma parameters in eruptive prominences.
Observation of the prominence cavity region using slitless eclipse flash spectra and space borne EUV filtergrams
Authors: Bazin Cyrille , Koutchmy Serge , Lamy Philippe , Tavabi Ehsan 
Published: January 2014

AbstractWe used total solar eclipse free of parasitic light for studying the prominence to corona interface, and the corresponding cavity in the context of the coronal physics. We analysed the visible continuum between the prominences to directly look at the electron density. We demonstrate some enhanced heating in the cavity region. Some similarities with the interface regions are shown: the photosphere to the chromosphere and the prominence to the corona interface. The optically thin neutral Helium at 4713 Å and the singly ionized Helium 4686 Å Paschen α lines are considered. We summed 80 slitless visible eclipse flash spectra that we compare with simultaneously obtained EUV SWAP/Proba2 174 Å images of ESA and AIA/SDO 171Å 193 Å 304 Å and 131 Å filtergrams. Intensity profiles in a radial direction are studied. We deduce the variation of the intensity ratio I(He I 4713) / I(He II 4686). Discussion: the temperature rises at the edge of the prominences. We evaluate for the first time with spectrophotometric accuracy the continuum modulations in prominence spectra. W-L intensity deficits are observed near the prominence boundaries in both eclipse spectra and in EUV images, confirming that the prominence -cavity regions correspond to a relative depression of plasma density of the surrounding corona. Conclusion: we demonstrate some enhanced heating occurring in these regions assuming hydrostatic equilibrium.
Initiation of Coronal Mass Ejections by Sunspot Rotation
Authors: Valori G. , Török T. , Temmer M. , Veronig A. M. , van Driel-Gesztelyi L. , Vršnak B. 
Published: January 2014

AbstractWe report observations of a filament eruption, two-ribbon flare, and coronal mass ejection (CME) that occurred in Active Region NOAA 10898 on 6 July 2006. The filament was located South of a strong sunspot that dominated the region. In the evolution leading up to the eruption, and for some time after it, a counter-clockwise rotation of the sunspot of about 30 degrees was observed. We suggest that the rotation triggered the eruption by progressively expanding the magnetic field above the filament. To test this scenario, we study the effect of twisting the initially potential field overlying a pre-existing flux rope, using three-dimensional zero–β MHD simulations. We consider a magnetic configuration whose photospheric flux distribution and coronal structure is guided by the observations and a potential field extrapolation. We find that the twisting leads to the expansion of the overlying field. As a consequence of the progressively reduced magnetic tension, the flux rope quasi-statically adapts to the changed environmental field, rising slowly. Once the tension is sufficiently reduced, a distinct second phase of evolution occurs where the flux rope enters an unstable regime characterized by a strong acceleration. Our simulation thus suggests a new mechanism for the triggering of eruptions in the vicinity of rotating sunspots.