Interferometry of ϵ\epsilon Aurigae: Characterization of the asymmetric eclipsing disk

We report on a total of 106 nights of optical interferometric observations of the $\epsilon$ Aurigae system taken during the last 14 years by four beam combiners at three different interferometric facilities. This long sequence of data provides an ideal assessment of the system prior to, during, and after the recent 2009-2011 eclipse. We have reconstructed model-independent images from the 10 in-eclipse epochs which show that a disk-like object is indeed responsible for the eclipse. Using new 3D, time-dependent modeling software, we derive the properties of the F-star (diameter, limb darkening), determine previously unknown orbital elements ($\Omega$, $i$), and access the global structures of the optically thick portion of the eclipsing disk using both geometric models and approximations of astrophysically relevant density distributions. These models may be useful in future hydrodynamical modeling of the system. Lastly, we address several outstanding research questions including mid-eclipse brightening, possible shrinking of the F-type primary, and any warps or sub-features within the disk.Comment: 105 pages, 57 figures. This is an author-created, un-copyedited version of an article accepted for publication in Astrophysical Journal Supplement Series. IOP Publishing Ltd is not responsible for any errors or omissions in this version of the manuscript or any version derived from i

Stellar Parameters for HD 69830, a Nearby Star with Three Neptune Mass Planets and an Asteroid Belt

We used the CHARA Array to directly measure the angular diameter of HD 69830, home to three Neptune mass planets and an asteroid belt. Our measurement of 0.674+/-0.014 milli-arcseconds for the limb-darkened angular diameter of this star leads to a physical radius of R$_*$ = 0.9058$\pm$0.0190 R\sun and luminosity of L* = 0.622+/-0.014 Lsun when combined with a fit to the spectral energy distribution of the star. Placing these observed values on an Hertzsprung-Russel (HR) diagram along with stellar evolution isochrones produces an age of 10.6+/-4 Gyr and mass of 0.863$\pm$0.043 M\sun. We use archival optical echelle spectra of HD 69830 along with an iterative spectral fitting technique to measure the iron abundance ([Fe/H]=-0.04+/-0.03), effective temperature (5385+/-44 K) and surface gravity (log g = 4.49+/-0.06). We use these new values for the temperature and luminosity to calculate a more precise age of 7.5+/-Gyr. Applying the values of stellar luminosity and radius to recent models on the optimistic location of the habitable zone produces a range of 0.61-1.44 AU; partially outside the orbit of the furthest known planet (d) around HD 69830. Finally, we estimate the snow line at a distance of 1.95+/-0.19 AU, which is outside the orbit of all three planets and its asteroid belt.Comment: 5 pages, 3 figures, accepted to Ap

Angular Diameters of the G Subdwarf μ\mu Cassiopeiae A and the K Dwarfs σ\sigma Draconis and HR 511 from Interferometric Measurements with the CHARA Array

Using the longest baselines of the CHARA Array, we have measured the angular diameter of the G5 V subdwarf $\mu$ Cas A, the first such determination for a halo population star. We compare this result to new diameters for the higher metallicity K0 V stars, $\sigma$ Dra and HR 511, and find that the metal-poor star, $\mu$ Cas A, has an effective temperature ($T_{\rm eff}=5297\pm32$ K), radius ($R=0.791\pm0.008 R_{\rm \odot}$), and absolute luminosity ($L=0.442\pm0.014 L_{\rm \odot}$) comparable to the other two stars with later spectral types. We show that stellar models show a discrepancy in the predicted temperature and radius for $\mu$ Cas A, and we discuss these results and how they provide a key to understanding the fundamental relationships for stars with low metallicity.Comment: Accepted for publication in The Astrophysical Journa

Stellar Diameters and Temperatures. I. Main-Sequence A, F, and G Stars

We have executed a survey of nearby, main-sequence A-, F-, and G-type stars with the CHARA Array, successfully measuring the angular diameters of forty-four stars with an average precision of ~1.5%. We present new measures of the bolometric flux, which in turn leads to an empirical determination of the effective temperature for the stars observed. In addition, these CHARA-determined temperatures, radii, and luminosities are fit to Yonsei-Yale model isochrones to constrain the masses and ages of the stars. These results are compared to indirect estimates of these quantities obtained by collecting photometry of the stars and applying them to model atmospheres and evolutionary isochrones. We find that for most cases, the models overestimate the effective temperature by ~1.5%-4% when compared to our directly measured values. The overestimated temperatures and underestimated radii in these works appear to cause an additional offset in the star's surface gravity measurements, which consequently yield higher masses and younger ages, in particular for stars with masses greater than ~1.3 M_☉. Additionally, we compare our measurements to a large sample of eclipsing binary stars, and excellent agreement is seen within both data sets. Finally, we present temperature relations with respect to (B – V) and (V – K) colors as well as spectral type, showing that calibration of effective temperatures with errors ~1% is now possible from interferometric angular diameters of stars

Architectures of the Text: An Inquiry Into the Hypnerotomachia Poliphili

Architectures of the Text: An Inquiry Into the Hypnerotomachia Poliphili A symposium to celebrate the acquisition of the second edition of the Hypnerotomachia Poliphili (1545) by the University of Pennsylvania Libraries. Website To download podcasts of the lectures, select the additional files below. Files in .mp4 format include images; files in .mp3 format are audio only. To download the symposium program, select download button at right. In April 2011, the University of Pennsylvania Libraries acquired a copy of the uncommon second edition of Francesco Colonna’s Hypnerotomachia Poliphili (Venice 1545). Since the appearance of the first edition in 1499, the Hypnerotomachia Poliphili has been heralded as the most beautiful book to appear in the Italian Renaissance. Printed in Venice by Aldus Manutius, “The Dream of Poliphily” was admired by Aldus’s contemporaries for its scholarship and value as an architectural treatise. Forty-six years after the publication of the first edition, Aldus’s heirs printed a second edition in 1545. This second edition suggests a renewed interest in the work, within Italy and beyond, for within a year a French translation appeared, followed by an English translation in 1592. Celebrated for its typographical design and illustrations, the Hypnerotomachia continues to attract the interest of scholars, typophiles, and collectors; it remains available in modern scholarly editions in both print and electronic format. The University of Pennsylvania Libraries\u27 acquisition came at the suggestion of John Dixon Hunt, Professor Emeritus of Landscape Architecture at the University. Funds for its purchase came from the G. Holmes Perkins Books and Archives Fund, established by G. Holmes Perkins, Professor of Architecture and Urbanism and former dean of the Graduate School of Fine Arts (now the School of Design). The Libraries and the School of Design administer this fund jointly. On February 11, 2012, the Anne and Jerome Fisher Fine Arts Library, the Rare Book and Manuscript Library, and the School of Design collaborated on a one-day symposium to celebrate the acquisition of the Hypnerotomachia. Presentations took place in the Class of \u2755 room, Van Pelt-Dietrich Library. Program: 10:30am-11:30am Movement 1: Books and Histories Welcome: David McKnight William B. Keller, Hypnerotomachia Joins the Perkins Library: Collecting to Support Persuasion in Architectural Design and History Eric Pumroy, Remarks on the 1499 Hypnerotomachia Poliphili at Bryn Mawr Special Collections John Dixon Hunt, Hypnerotomachia Poliphili: A Child\u27s Guide to the Story Line and a Look at its Afterlives Lynne Farrington, \u27Though I could lead a quiet and peaceful life, I have chosen one full of toil and trouble\u27: Aldus Manutius and the Printing History of the Hypnerotomachia Poliphili 11:30am-1:00pm Movement 2: Words and Interpretations Victoria Kirkham, Hypno What? A Dreamer\u27s Vision and the Reader\u27s Nightmare Ann Moyer, The Wanderings of Poliphilo through Renaissance Studies Ian White, Multiple Words, Multiple Meanings in the Hypnerotomachia 2:00pm-3:00pm Movement 3: Art and Illustration Chris Nygren, The Hypnerotomachia and Italian Art Circa 1500 Larry Silver, Not Hypnerotomachia: Venice\u27s Other Early Woodcut Illustrations 3:00pm-4:30pm Movement 4: Imagined Architectures Raffaella Fabiani Giannetto, \u27Not before either known or dreamt of\u27: The Hypnerotomachia Poliphili and the Craft of Wonder David Leatherbarrow, What Fragments are to Desire, Elements are to Design Ian White, Mathematical Design in Poliphilo\u27s Imaginary Building, The Temple of Venus 4:30pm-5:00pm Break and Interlude Shushi Yoshinaga, Hypnerotomachia Poliphili: A Modern Heritage : a display of objects and images 5:00pm-6:00pm Movement 5: Contemporary Resonances and Final Observation

e-Social Science and Evidence-Based Policy Assessment : Challenges and Solutions

Peer reviewedPreprin

Spectroscopy, MOST Photometry, and Interferometry of MWC 314: Is it an LBV or an interacting binary?

MWC 314 is a bright candidate luminous blue variable that resides in a fairly close binary system, with an orbital period of 60.753$\pm$0.003 d. We observed MWC 314 with a combination of optical spectroscopy, broad-band ground- and space-based photometry, as well as with long baseline, near-infrared interferometry. We have revised the single-lined spectroscopic orbit and explored the photometric variability. The orbital light curve displays two minima each orbit that can be partially explained in terms of the tidal distortion of the primary that occurs around the time of periastron. The emission lines in the system are often double-peaked and stationary in their kinematics, indicative of a circumbinary disc. We find that the stellar wind or circumbinary disc is partially resolved in the K\prime-band with the longest baselines of the CHARA Array. From this analysis, we provide a simple, qualitative model in an attempt to explain the observations. From the assumption of Roche Lobe overflow and tidal synchronisation at periastron, we estimate the component masses to be M1 $\approx 5$ M$_\odot$ and M2$\approx 15$ M$_\odot$, which indicates a mass of the LBV that is extremely low. In addition to the orbital modulation, we discovered two pulsational modes with the MOST satellite. These modes are easily supported by a low-mass hydrogen-poor star, but cannot be easily supported by a star with the parameters of an LBV. The combination of these results provides evidence that the primary star was likely never a normal LBV, but rather is the product of binary interactions. As such, this system presents opportunities for studying mass-transfer and binary evolution with many observational techniques.Comment: 26 pages, 7 figures, 5 tables, 2 appendices with 7 additional tables and 2 additional figures. Accepted for publication in MNRA

Assessment of the Variability in Influenza A(H1N1) Vaccine Effectiveness Estimates Dependent on Outcome and Methodological Approach

Estimation of Influenza vaccine effectiveness (VE) varies with study design, clinical outcome 10 considered and statistical methodology used. By estimating VE using differing outcomes and 11 statistical methods on the same cohort of individuals the variability in the estimates produced can 12 be better understood. The Pandemic Influenza Primary Care Reporting (PIPeR) cohort of approximately 193,000 individuals 14 was used to estimate pandemic VE in Scotland during season 2009-10. VE results for three 15 outcomes; influenza related consultations, virological confirmed influenza and death were 16 considered. Use of individualised records allowed all models to be adjusted for age, sex, 17 deprivation, risk status relating to chronic illnesses, seasonal vaccination status and a marker of the 18 individual’s propensity to consult. For the consultation and death outcomes, VE was calculated by 19 comparing consultation rates in the unvaccinated and vaccinated groups, adjusted for the listed 20 factors, using both Cox and Poisson regression models. For the consultation outcome, the 21 unvaccinated group was split into individuals before vaccination and those never vaccinated to allow 22 for potential differences in the health seeking behaviour of these groups. For the virology outcome 23 estimates were calculated using a generalised additive logistic regression model. All models were 24 adjusted for time. Vaccine effect was demonstrated for the influenza-like illness consultation outcome using the Cox 26 model (VE=49% 95% CI (19%, 67%)) with lower estimates from the model splitting the before and 27 never vaccinated groups (VE=34.2% with 95% CI (-0.5%, 58.9%)). Vaccine effect was also illustrated 28 for overall mortality (VE=40% (95% CI 18%, 56%)) and a virological confirmed subset of symptomatic 29 individuals (VE=60% (95% CI -38%, 89%))