Northwest Africa 8418: The first CV4 chondrite     

G. J. MacPherson  K. Nagashima  A. N. Krot  S. M. Kuehner  A. J. Irving  K. Ziegler  L. Mallozzi  C. Corrigan  D. Pitt 《Meteoritics & planetary science》2023,58(1):135-157

Northwest Africa (NWA) 8418 is an unusual chondrite whose properties do not exactly match those of any other known chondrite. It has similarities to the CV (Vigarano group), CK (Karoonda group), and CL (Loongana group) chondrites, but its abundance of large calcium-aluminum-rich inclusions (CAIs) and the low NiO content (<0.2 wt%) of its matrix olivine ally it most closely with the CV group. The absence of grossular, monticellite, wollastonite, and sodalite from the alteration products of the CAIs; the magnesium-rich nature of the matrix olivines (Fa₃₈) relative to that of the CV3 chondrites (~Fa₅₀); and the presence of secondary Na-bearing plagioclase and chlorapatite indicate a metamorphic temperature >600 °C. NWA 8418 contains kamacite, taenite, and troilite, and lacks magnetite and pentlandite. We propose that NWA 8418 be reclassified as a reduced CV4 chondrite, which makes it the first CV chondrite of petrologic type 4.  相似文献   

Constraints on the luminosities of gamma-ray bursts     

Hakkila  J.  Meegan  C.  Horack  J.  Pendleton  G.  Briggs  M.  Paciesas  W.  Emslie  G.  Mallozzi  R. 《Astrophysics and Space Science》1995,231(1-2):369-372

Constraints are found on the gamma-ray burst luminosity function from an analysis of the combined BATSE/PVO intensity distribution. If bursts originate in an extended Galactic halo, then the intrinsic luminosity range is narrow, with bursts spanning only a factor of five or less in luminosity. If bursts originate in a simple Friedmann cosmology with = 1 and = 0, then very few luminosity constraints exist.National Research Council Fellow at NASA/MSFC  相似文献