The brightest asymptotic giant branch stars in the Leo I dwarf spheroidal galaxy     

John Menzies  Michael Feast  Toshihiko Tanabé  Patricia Whitelock  Yoshikazu Nakada 《Monthly notices of the Royal Astronomical Society》2002,335(4):923-927

  相似文献   

Wide Field Imaging and the Velocity Structure in the Coma of Hale–Bopp     

Harris  Walter M.  Morgenthaler  Jeffrey P.  Scherb  Frank  Anderson  Christopher  Oliversen  Ronald J. 《Earth, Moon, and Planets》2002,90(1-4):45-56

The comae of very active comets have a substantiallymore complex coma than their weaker cousins.The primary cause of this is photolytic heating and collisionsthat occur over an ever-larger volume of the coma asQ_{H 2O} increases. Collisionswith the photochemical daughters ofwater in this regionmodify the radial distributions and outflowvelocity of each species, excite and quench metastableemissions, and introduce velocity gradients from photolyticheating. Comet Hale–Bopp was the first comet forwhich the collisional coma was both spatially resolvableand comparable in extent to the scale lengths ofmajor coma species. In the case of this object,the classical assumptions that make it possible toinvert radial emission line profiles, brightnesses, andlineshapes to production rate and velocity eitherdo not hold or require adjustment to work.Here we describe how a large collision zone modifies thecoma, how it affects the classical methods for obtainingproduction rate and velocity, and discuss how wide fieldimaging may be combined with modified versions ofsimple models to address the complications and extract somestructural information.  相似文献   

Water within,moving through,and shaping the Earth's surface: Introducing a special issue on water in the critical zone     

Ying Fan  Gordon Grant  Suzanne P. Anderson 《水文研究》2019,33(25):3146-3151

  相似文献   

EMERGING SOUTHEAST ASIA. A STUDY IN GROWTH AND STAGNATION. By Donald W. Fryer.     

A. G. Anderson 《New Zealand geographer》1971,27(2):216-218

  相似文献   

Direct-Drive Inertial Confinement Fusion Implosions on Omega     

S. P. Regan  T. C. Sangster  D. D. Meyerhofer  K. Anderson  R. Betti  T. R. Boehly  T. J. B. Collins  R. S. Craxton  J. A. Delettrez  R. Epstein  O. V. Gotchev  V. Yu. Glebov  V. N. Goncharov  D. R. Harding  P. A. Jaanimagi  J. P. Knauer  S. J. Loucks  L. D. Lund  J. A. Marozas  F. J. Marshall  R. L. Mccrory  P. W. Mckenty  S. F. B. Morse  P. B. Radha  W. Seka  S. Skupsky  H. Sawada  V. A. Smalyuk  J. M. Soures  C. Stoeckl  B. Yaakobi  J. A. Frenje  C. K. Li  R. D. Petrasso  F. H. SÉguin 《Astrophysics and Space Science》2005,298(1-2):227-233

  相似文献   

A laboratory survey of the thermal desorption of astrophysically relevant molecules     

Mark P. Collings  Mark A. Anderson  Rui Chen  John W. Dever  Serena Viti  David A. Williams  Martin R. S. McCoustra 《Monthly notices of the Royal Astronomical Society》2004,354(4):1133-1140

  相似文献   

The 2003 shell event in η Carinae     

Patricia A. Whitelock  Michael W. Feast  Freddy Marang  Elmé Breedt 《Monthly notices of the Royal Astronomical Society》2004,352(2):447-456

  相似文献   

The case for asymmetric dust around a C-rich asymptotic giant branch star     

Michael W. Feast  Patricia A. Whitelock  Freddy Marang 《Monthly notices of the Royal Astronomical Society》2003,346(3):878-884

JHKL observations of the mass-losing carbon Mira variable IRAS 15194–5115 (II Lup) extending over about 18 yr are presented and discussed. The pulsation period is 575 d and has remained essentially constant over this time span. The star has undergone an extensive obscuration minimum during this time. This is complex and, like such minima in similar objects (e.g. R For), does not fit the model predictions of a simple long-term periodicity. Together with the high-resolution observations of Lopez et al., the results suggest that the obscuration changes are caused by the formation of dust clouds of limited extent in the line of sight. This is an R Coronae Borealis-type (RCB-type) model. The effective reddening law at J and H is similar to that found for R For.  相似文献   

Editorial     

E. W. Anderson 《GeoJournal》1997,41(2):99-100

  相似文献   

The Vicência meteorite fall: A new unshocked (S1) weakly metamorphosed (3.2) LL chondrite          下载免费PDF全文

Klaus Keil  Maria E. Zucolotto  Alexander N. Krot  Patricia M. Doyle  Myriam Telus  Tatiana V. Krot  Richard C. Greenwood  Ian A. Franchi  John T. Wasson  Kees C. Welten  Marc W. Caffee  Derek W. G. Sears  My Riebe  Rainer Wieler  Edivaldo dos Santos  Rosa B. Scorzelli  Jerome Gattacceca  France Lagroix  Matthias Laubenstein  Julio C. Mendes  Philippe Schmitt‐Kopplin  Mourad Harir  Andre L. R. Moutinho 《Meteoritics & planetary science》2015,50(6):1089-1111

The Vicência meteorite, a stone of 1.547 kg, fell on September 21, 2013, at the village Borracha, near the city of Vicência, Pernambuco, Brazil. It was recovered immediately after the fall, and our consortium study showed it to be an unshocked (S1) LL3.2 ordinary chondrite. The LL group classification is based on the bulk density (3.13 g cm^?3); the chondrule mean apparent diameter (0.9 mm); the bulk oxygen isotopic composition (δ¹⁷O = 3.768 ± 0.042‰, δ¹⁸O = 5.359 ± 0.042‰, Δ¹⁷O = 0.981 ± 0.020‰); the content of metallic Fe,Ni (1.8 vol%); the Co content of kamacite (1.73 wt%); the bulk contents of the siderophile elements Ir and Co versus Au; and the ratios of metallic Fe⁰/total iron (0.105) versus total Fe/Mg (1.164), and of Ni/Mg (0.057) versus total Fe/Mg. The petrologic type 3.2 classification is indicated by the beautifully developed chondritic texture, the standard deviation (~0.09) versus mean Cr₂O₃ content (~0.14 wt%) of ferroan olivine, the TL sensitivity and the peak temperature and peak width at half maximum, the cathodoluminescence properties of chondrules, the content of trapped ¹³²Xe_tr (0.317 × 10^?8cm³STP g^?1), and the Raman spectra for organic material in the matrix. The cosmic ray exposure age is ~72 Ma, which is at the upper end of the age distribution of LL group chondrites. The meteorite is unusual in that it contains relatively large, up to nearly 100 μm in size, secondary fayalite grains, defined as olivine with Fa_>75, large enough to allow in situ measurement of oxygen and Mn‐Cr isotope systematics with SIMS. Its oxygen isotopes plot along a mass‐dependent fractionation line with a slope of ~0.5 and Δ¹⁷O of 4.0 ± 0.3‰, and are similar to those of secondary fayalite and magnetite in the unequilibrated chondrites EET 90161, MET 96503, and Ngawi. These data suggest that secondary fayalite in Vicência was in equilibrium with a fluid with a Δ¹⁷O of ~4‰, consistent with the composition of the fluid in equilibrium with secondary magnetite and fayalite in other unequilibrated ordinary chondrites. Secondary fayalite and the chondrule olivine phenocrysts in Vicência are not in isotopic equilibrium, consistent with low‐temperature formation of fayalite during aqueous alteration on the LL parent body. That alteration, as dated by the ⁵³Mn‐⁵³Cr chronology age of secondary fayalite, took place $4.0{}_{?1.1}^{+1.4}$ Ma after formation of CV CAIs when anchored to the quenched angrite D'Orbigny.  相似文献