CONSIDERAZIONI SISTEMATICHE E COROLOGICHE SUL GEN. CONDICA WLK. 1856 (= PLATYSENTA GROTE, 1874), (LEPID.- NOCTUIDAE) CON RIFERIMENTO ALLA NUOVA SPECIE C EUROPAEA PARENZAN, PRIMA DEL GENERE RINVENUTA NELL'EUROPA CONTINENTALE

The Author gives some systematic and chorologic considerations on the gen. Condica Wlk. 1856 (= Platysenta Grote, 1874) (Lepidoptera-Noctuidae), after discovering of Condica europaea Parenzan, 1980. This is :first record of genus reported for continental Europe. Two new Subgenera (Monocondica n. Sgen., Bicondica n. Sgen.) are described, and some synonymycal notes are reported. Di alcune delle specie appartenenti al Subgen. Platysenta dò la figura della valva destra per raffronto con la nuova specie, Candica europaea Par.È evidente che quest'ultima costituisce il primo reperto di una Candica catturata nell'Italia meridionale e nell'intera Europa continentale. Osservo che essa si distingue dalle altre congeneriche anche per avere l'apice delle ali anteriori leggermente più appuntito delle altre specie simili.

Spectral and spatial imaging of the Be+sdO binary phi Persei

The rapidly rotating Be star phi Persei was spun up by mass and angular momentum transfer from a now stripped-down, hot subdwarf companion. Here we present the first high angular resolution images of phi Persei made possible by new capabilities in longbaseline interferometry at near-IR and visible wavelengths. We observed phi Persei with the MIRC and VEGA instruments of the CHARA Array. Additional MIRC-only observations were performed to track the orbital motion of the companion, and these were fit together with new and existing radial velocity measurements of both stars to derive the complete orbital elements and distance. The hot subdwarf companion is clearly detected in the near-IR data at each epoch of observation with a flux contribution of 1.5% in the H band, and restricted fits indicate that its flux contribution rises to 3.3% in the visible. A new binary orbital solution is determined by combining the astrometric and radial velocity measurements. The derived stellar masses are 9.6+-0.3Msol and 1.2+-0.2Msol for the Be primary and subdwarf secondary, respectively. The inferred distance (186 +- 3 pc), kinematical properties, and evolutionary state are consistent with membership of phi Persei in the alpha Per cluster. From the cluster age we deduce significant constraints on the initial masses and evolutionary mass transfer processes that transformed the phi Persei binary system. The interferometric data place strong constraints on the Be disk elongation, orientation, and kinematics, and the disk angular momentum vector is coaligned with and has the same sense of rotation as the orbital angular momentum vector. The VEGA visible continuum data indicate an elongated shape for the Be star itself, due to the combined effects of rapid rotation, partial obscuration of the photosphere by the circumstellar disk, and flux from the bright inner disk.Comment: 16 pages, 6 figures, 1 Anne

Single-Mode versus multimode interferometry: a performance study

We compare performances of ground-based single-mode and multimode (speckle) interferometers in the presence of partial Adaptive Optics correction of atmospheric turbulence. It is first shown that for compact sources (i.e. sources smaller than the Airy disk of a single telescope) not entirely resolved by the interferometer, the remarkable property of spatial filtering of single-mode waveguides coupled with AO correction significantly reduces the speckle noise which arises from residual wavefront corrugations. Focusing on those sources, and in the light of the AMBER experiment (the near infrared instrument of the VLTI), we show that single-mode interferometry produces a better Signal-to-Noise Ratio on the visibility than speckle interferometry. This is true for bright sources (K < 5), and in any case as soon as Strehl ratio of 0.2 is achieved. Finally, the fiber estimator is much more robust -- by two orders of magnitude -- than the speckle estimator with respect to Strehl ratio variations during the calibration procedure. The present analysis theoretically explains why interferometry with fibers can produce visibility measurements with a very high precision, 1% or lessComment: 13 pages (5 pages of appendices), 6 figures to be published in A&

High-dispersion spectroscopic monitoring of the Be/X-ray binary A0535+26/V725 Tau I: The long-term profile variability

We report on optical high-dispersion spectroscopic monitoring observations of the Be/X-ray binary A0535+26/V725 Tau, carried out from November 2005 to March 2009. The main aim of these monitoring observations is to study spectral variabilities in the Be disc, on both the short (a week or so) and long (more than hundreds of days) timescales, by taking long-term frequent observations. Our four-year spectroscopic observations indicate that the V/R ratio, i.e., the relative intensity of the violet (V) peak to the red (R) one, of the double-peaked H-alpha line profile varies with a period of 500 days. The H-beta line profile also varies in phase with the H-alpha profile. With these observations covering two full cycles of the V/R variability, we reconstruct the 2-D structure of the Be disc by applying the Doppler tomography method to the H-alpha and H-beta emission line profiles, using a rigidly rotating frame with the V/R variability period. The resulting disc structure reveals non-axisymmetric features, which can be explained by a one-armed perturbation in the Be disc. It is the first time that an eccentric disc structure is directly detected by using a method other than the interferometric one.Comment: (10 pages, 9 figures, accepted to MNRAS

Line Forces in Keplerian Circumstellar Disks and Precession of Nearly Circular Orbits

We examine the effects of optically thick line forces on orbiting circumstellar disks, such as occur around Be stars. For radially streaming radiation, line forces are only effective if there is a strong radial velocity gradient, as occurs, for example, in a line-driven stellar wind. However, within an orbiting disk, the radial shear of the azimuthal velocity leads to strong line-of-sight velocity velocity gradients along nonradial directions. As such, in the proximity of a stellar surface extending over a substantial cone angle, the nonradial stellar radiation can impart a significant line force, even in the case of purely circular orbits. Given the highly supersonic nature of orbital velocity variations, we use the Sobolev approximation, thereby extending to the disk case the standard CAK formalism developed for line-driven winds. We delineate the parameter regimes for which radiative forces might alter disk properties; but even when radiative forces are small, we analytically quantify higher-order effects in the linear limit, including the precession of weakly elliptical orbits. We find that optically thick line forces can have observable implications for the dynamics of disks around Be stars, including the generation of either prograde or retrograde precession in slightly eccentric orbits. However, our analysis suggests a net retrograde effect, in apparent contradiction with observed long-term variations of violet/red line profile asymmetries from Be stars, which are generally thought to result from prograde propagation of a so-called ``one arm mode''. We also conclude that radiative forces may alter the dynamical properties at the surface of the disk where disk winds originate, and may even make low-density disks vulnerable to being blown away.Comment: 31 pages, Latex, aaspp4 macro, 4 figure

Multi-epoch Near-Infrared Interferometry of the Spatially Resolved Disk Around the Be Star Zeta Tau

We present interferometric observations of the Be star Zeta Tau obtained using the MIRC beam combiner at the CHARA Array. We resolved the disk during four epochs in 2007-2009. We fit the data with a geometric model to characterize the circumstellar disk as a skewed elliptical Gaussian and the central Be star as a uniform disk. The visibilities reveal a nearly edge-on disk with a FWHM major axis of ~ 1.8 mas in the H-band. The non-zero closure phases indicate an asymmetry within the disk. Interestingly, when combining our results with previously published interferometric observations of Zeta Tau, we find a correlation between the position angle of the disk and the spectroscopic V/R ratio, suggesting that the tilt of the disk is precessing. This work is part of a multi-year monitoring campaign to investigate the development and outward motion of asymmetric structures in the disks of Be stars.Comment: Accepted for publication in the Astronomical Journal. 27 pages, 7 Figure

Constraining Disk Parameters of Be Stars using Narrowband H-alpha Interferometry with the NPOI

Interferometric observations of two well-known Be stars, gamma Cas and phi Per, were collected and analyzed to determine the spatial characteristics of their circumstellar regions. The observations were obtained using the Navy Prototype Optical Interferometer equipped with custom-made narrowband filters. The filters isolate the H-alpha emission line from the nearby continuum radiation, which results in an increased contrast between the interferometric signature due to the H-alpha-emitting circumstellar region and the central star. Because the narrowband filters do not significantly attenuate the continuum radiation at wavelengths 50 nm or more away from the line, the interferometric signal in the H-alpha channel is calibrated with respect to the continuum channels. The observations used in this study represent the highest spatial resolution measurements of the H-alpha-emitting regions of Be stars obtained to date. These observations allow us to demonstrate for the first time that the intensity distribution in the circumstellar region of a Be star cannot be represented by uniform disk or ring-like structures, whereas a Gaussian intensity distribution appears to be fully consistent with our observations.Comment: 23 pages, 14 figures, accepted for publication in A

An investigation of the close environment of beta Cep with the VEGA/CHARA interferometer

High-precision interferometric measurements of pulsating stars help to characterize their close environment. In 1974, a close companion was discovered around the pulsating star beta Cep using the speckle interferometry technique and features at the limit of resolution (20 milli-arcsecond or mas) of the instrument were mentioned that may be due to circumstellar material. Beta Cep has a magnetic field that might be responsible for a spherical shell or ring-like structure around the star as described by the MHD models. Using the visible recombiner VEGA installed on the CHARA long-baseline interferometer at Mt. Wilson, we aim to determine the angular diameter of beta Cep and resolve its close environment with a spatial resolution up to 1 mas level. Medium spectral resolution (R=6000) observations of beta Cep were secured with the VEGA instrument over the years 2008 and 2009. These observations were performed with the S1S2 (30m) and W1W2 (100m) baselines of the array. We investigated several models to reproduce our observations. A large-scale structure of a few mas is clearly detected around the star with a typical flux relative contribution of 0.23 +- 0.02. Our best model is a co-rotational geometrical thin ring around the star as predicted by magnetically-confined wind shock models. The ring inner diameter is 8.2 +- 0.8 mas and the width is 0.6 +- 0.7 mas. The orientation of the rotation axis on the plane of the sky is PA = 60 +- 1 deg, while the best fit of the mean angular diameter of beta Cep gives UD[V] = 0.22 +- 0.05 mas. Our data are compatible with the predicted position of the close companion of beta Cep. These results bring additional constraints on the fundamental parameters and on the future MHD and asteroseismological models of the star.Comment: Paper accepted for publication in A&A (in press

Morganella morganii septicemia and concurrent renal crassicaudiasis in a Cuvier’s beaked whale (Ziphius cavirostris) stranded in Italy

Information regarding bacterial diseases in Cuvier's beaked whale (CBW, Ziphius cavirostris) is scattered and mostly incomplete. This report describes a case of septicemia by Morganella morganii in a juvenile male CBW with concurrent renal crassicaudiasis. The animal stranded along the Ligurian coastline (Italy) and underwent a systematic post-mortem examination to determine the cause of death. Histopathology showed lesions consistent with a septicemic infection, severe meningoencephalitis, and renal crassicaudiasis. An M. morganii alpha-hemolytic strain was isolated in pure culture from liver, lung, prescapular lymph node, spleen, hepatic and renal abscesses, and central nervous system (CNS). The antimicrobial susceptibility profile of the strain was evaluated with the minimum inhibitory concentrations (MICs) method and reduced susceptibility to Trimethoprim-Sulfamethoxazole is reported. Crassicauda sp. nematodes were retrieved from both kidneys. No other pathogens were detected by immunohistochemistry, serology, or biomolecular analyses. Toxicological investigations detected high concentrations of immunosuppressant pollutants in the blubber. The chronic parasitic infestation and the toxic effects of xenobiotics likely compromised the animal's health, predisposing it to an opportunistic bacterial infection. To our knowledge, this is the first description of M. morganii septicemia with CNS involvement in a wild cetacean