An Ensemble Study of a January 2010 Coronal Mass Ejection (CME): Connecting a Non-obvious Solar Source with Its ICME/Magnetic Cloud     

D. F. Webb  M. M. Bisi  C. A. de Koning  C. J. Farrugia  B. V. Jackson  L. K. Jian  N. Lugaz  K. Marubashi  C. Möstl  E. P. Romashets  B. E. Wood  H.-S. Yu 《Solar physics》2014,289(11):4173-4208

A distinct magnetic cloud (MC) was observed in-situ at the Solar TErrestrial RElations Observatory (STEREO)-B on 20?–?21 January 2010. About three days earlier, on 17 January, a bright flare and coronal mass ejection (CME) were clearly observed by STEREO-B, which suggests that this was the progenitor of the MC. However, the in-situ speed of the event, several earlier weaker events, heliospheric imaging, and a longitude mismatch with the STEREO-B spacecraft made this interpretation unlikely. We searched for other possible solar eruptions that could have caused the MC and found a faint filament eruption and the associated CME on 14?–?15 January as the likely solar source event. We were able to confirm this source by using coronal imaging from the Sun Earth Connection Coronal and Heliospheric Investigation (SECCHI)/EUVI and COR and Solar and Heliospheric Observatory (SOHO)/Large Angle and Spectrometric Coronograph (LASCO) telescopes and heliospheric imaging from the Solar Mass Ejection Imager (SMEI) and the STEREO/Heliospheric Imager instruments. We use several empirical models to understand the three-dimensional geometry and propagation of the CME, analyze the in-situ characteristics of the associated ICME, and investigate the characteristics of the MC by comparing four independent flux-rope model fits with the launch observations and magnetic-field orientations. The geometry and orientations of the CME from the heliospheric-density reconstructions and the in-situ modeling are remarkably consistent. Lastly, this event demonstrates that a careful analysis of all aspects of the development and evolution of a CME is necessary to correctly identify the solar counterpart of an ICME/MC.  相似文献   

Optical depths and time-scale distributions in Galactic microlensing     

Alexander Wood  Shude Mao 《Monthly notices of the Royal Astronomical Society》2005,362(3):945-951

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Discovery of the 'missing' mode in HR 1217 by the Whole Earth Telescope     

D. W.Kurtz  S. D.Kawaler  R. L.Riddle  M. D.Reed †  M. S.Cunha  M.Wood  N.Silvestri  T. K.Watson  N.Dolez  P.Moskalik  S.Zola  E.Pallier  J. A.Guzik  T. S.Metcalfe  A. S.Mukadam  R. E.Nather  D. E.Winget  D. J.Sullivan  T.Sullivan  K.Sekiguchi  X.Jiang  R.Shobbrook  B. N.Ashoka  S.Seetha  S.Joshi  D.O'Donoghue  G.Handler  M.Mueller  J. M.Gonzalez Perez  J.-E.Solheim  F.Johannessen  A.Ulla  S. O.Kepler  A.Kanaan  A.da Costa  L.Fraga  O.Giovannini  J. M.Matthews 《Monthly notices of the Royal Astronomical Society》2002,330(3):57-61

HR 1217 is a prototypical rapidly oscillating Ap star that has presented a test to the theory of non-radial stellar pulsation. Prior observations showed a clear pattern of five modes with alternating frequency spacings of 33.3 and 34.6 μHz, with a sixth mode at a problematic spacing of 50.0 μHz (which equals  1.5×33.3 μHz)  to the high-frequency side. Asymptotic pulsation theory allowed for a frequency spacing of 34 μHz, but Hipparcos observations rule out such a spacing. Theoretical calculations of magnetoacoustic modes in Ap stars by Cunha predicted that there should be a previously undetected mode 34 μHz higher than the main group, with a smaller spacing between it and the highest one. In this Letter, we present preliminary results from a multisite photometric campaign on the rapidly oscillating Ap star HR 1217 using the 'Whole Earth Telescope'. While a complete analysis of the data will appear in a later paper, one outstanding result from this run is the discovery of a newly detected frequency in the pulsation spectrum of this star, at the frequency predicted by Cunha.  相似文献   

Results from the Wide Angle Search for Planets Prototype (WASP0) – II. Stellar variability in the Pegasus field     

Stephen R. Kane  T. A. Lister  rew Collier Cameron  Keith Horne  David James  Don L. Pollacco  Rachel A. Street  Yiannis Tsapras 《Monthly notices of the Royal Astronomical Society》2005,362(1):117-126

Recent wide field photometric surveys, which target a specific field for long durations, are ideal for studying both long- and short-period stellar variability. Here, we report on 75 variable stars detected during the observations of a field in Pegasus using the Wide Angle Search for Planets Prototype (WASP0) instrument, 73 of which are new discoveries. The variables detected include 16 δ Scuti stars, 34 eclipsing binaries, 3 BY Draconis stars and 4 RR Lyraes. We estimate that the fraction of stars in the field brighter than   V ∼ 13.5  exhibiting variable behaviour with an amplitude greater than 0.6 per cent rms is ∼0.4 per cent. These results are compared with other wide field stellar variability surveys, and implications for detecting transits due to extra-solar planets are discussed.  相似文献   

Candidate extrasolar planet transits discovered in the Microlensing Observations in Astrophysics-I Galactic bulge data     

F. Abe  I. A. Bond  Y. Furuta  J. B. Hearnshaw  P. M. Kilmartin  Y. Kurata  K. Masuda  Y. Matsubara  Y. Muraki  S. Noda  K. Okajima  N. J. Rattenbury  T. Sako  D. J. Sullivan  T. Sumi  P. Tristram  J. N. Wood  T. Yanagisawa  P. C. M. Yock 《Monthly notices of the Royal Astronomical Society》2005,364(1):325-334

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Intrinsic galaxy alignments from the 2SLAQ and SDSS surveys: luminosity and redshift scalings and implications for weak lensing surveys     

Christopher M. Hirata  Rachel Mandelbaum †  Mustapha Ishak  Uro&#; Seljak  Robert Nichol  Kevin A. Pimbblet  Nicholas P. Ross  David Wake 《Monthly notices of the Royal Astronomical Society》2007,381(3):1197-1218

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Surface deformation in the Santa Cruz Mountains: the 17th October 1989 Loma Prieta earthquake     

Robert Muir Wood 《地学学报》1989,1(5):480-484

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Analyzing hydrologic uncertainty and its impact upon decision making in water resources     

Eric F. Wood 《Advances in water resources》1978,1(5):299-305

Bayesian Inference and Decision Theory tools are applied to the problem of synthetic hydrology when model and parameter uncertainty exist. Issues such as optimal parameter estimation, use of synthetic generation in design problems, and the effects of parameter uncertainty on statistical estimation are discussed and applied to the problem of reservoir slorage-yield analysis.  相似文献   

Metallothioneins and trace metals in the dogwhelk Nucella lapillus (L.) collected from Icelandic coasts     

Leung KM  Dewhurst RE  Halldórsson H  Svavarsson J 《Marine pollution bulletin》2005,51(8-12):729-737

Different sizes of the dogwhelk Nucella lapillus were collected from eight locations along the southwest and north coasts of Iceland. Concentrations of total metallothioneins (MTs) and heavy metals (Cd, Cu, Cr, Mn, Ni, and Zn) were analysed using the silver saturation method and inductively coupled plasma-atomic emission spectrometry. The level of tributyltin (TBT) contamination was also assessed using imposex indices, the vas deferens stage index (VDSI) and relative penis size index (RPSI). Gufunes N. lapillus presented the highest values of VDSI (4.0) and RPSI (11.1), followed by Grenivík individuals (VDSI = 3.0; RPSI = 0.9), while the Strandakirkja population showed the lowest VDSI (0.3) and zero RPSI. At a standardised size (0.25 g dry soft-body weight), Grenivík N. lapillus exhibited significantly higher concentrations of all metals whereas overall metal concentrations were significantly lower in individuals from Strandakirkja and Garðskagi compared to other study sites. Partial correlation analyses with size correction indicated that MT concentrations were better correlated with Cd and Cu concentrations than with other metals. At the standard size, the pattern of MT concentrations in N. lapillus from different sites was, however, very different from those of metal profiles. Such discrepancies between the patterns of MT and metals in N. lapillus might be explained by the fact that MT induction could be influenced by various factors such as temperature, dietary metal intake, growth rate and co-existence of other MT-inducing chemicals.  相似文献   

A constitutive model for sand in triaxial compression     

R. Nova  D. M. Wood 《国际地质力学数值与分析法杂志》1979,3(3):255-278

Although there is a large number of constitutive models for sand available in the literature it is believed that a fresh approach, striking a balance between complexity and theoretical rigour, is desirable. The approach here has certain conceptual links with the Cam Clay series of elastic–plastic models, but includes the more general starting assumption that the yield function, plastic potential and failure locus should be given quite distinct mathematical expressions. Possible physical bases for the proposed forms are discussed. Ways in which the parameters required to define the model may be determined are suggested and the use of the model is then demonstrated. Firstly, it is shown that, where a limited set of experimental data is available, the model is flexible enough to be able to match the test results. Secondly, it is shown that, where a wide range of test results has been produced, it is possible to determine the model constitutive parameters from a small number of tests and proceed to make satisfactory predictionsfor other, quite different, types of test. The model is developed for sand at a single initial density, but the way in which the constitutive parameters might be expected to vary with density is discussed. The model is described for conditions of triaxial compression, and extension to more general stress states will be needed before it can be put to the test of incorporation in, for example, a finite element program.  相似文献