tial & SE ae ee 6k tas ac a liball a we a em ee arama eat ag PHYSICS (GENERAL) Astrophysics and Cosmology Cosmic Ray Exposure Ages 9934 RUE BIATUM-S PRON THOM SPU bIES ON BLACK HY PL RE SETH NE CHONTRI ERS: Goputan, bh. J.C BRPERC Ps OD siboCN (bas, of Catitetnat, Lo yhis, Res. (62 Na, fo, med AND REEHEAA LING, caseb sj; Wetherill, GW, OG Dee bua). Whoooroc\ Rl sr dati were med ater tor to hypersthenc chee rote. usudiy dab, dochondrites. Tee dait pr ippeared focay been the me stheaah shoe wd. nd teheated, Sever. dens ts rractiops for tweeot the blreb oc aedrites, Oost. aed Mieprington were sepairdted, mie RE Sr anadvses wer pepe fenited. Whoto -roch data tor observed black Ayporstiene Lalla camber dewithin experrmentiberrant fo the boca di Gs pate yecrr te ochron defined by other chonartes, AMhough black ‘finds’ plotted untoruiy to the left of the meochron, this behivier was also shown bs unshocked finds, Theretore the total-rocl dita did not reseatany signilicant shoele or reneating Ciects. The density sepirates, particularly those of Oreiaie, departed «ign tie rathy trom the +.5-b.y. isochion. \Whoush tneir “Rb; Sr riftas variwd from 6.5 to 1.4, ther 8'8r “Sr ratios were the same is that of the total meteorite fo wrhin 6,002. This simitarity resulted ina hearly horizontal distribution of points on a Sr evolution diagram. To a lesser extent, dtfa trem Purmington also showed the sime effect. It was canclauded that this buiaior is dae te partial homogeni/ation of the Sr isotopes witha these two meteorites, ery recenth an thes history. ‘Ehe seatter mm the eit prectuded any preere determin ition et the time ot fheoovent. © uth) ener crents NNCA tltnetAE aineal cl, oathcellOLNRe datetis! saathem meine 9) tis ein oe me a FP HIGH-ASGULAR-RESOLU TION ASTROPHYSICAL 9935 OBSERVA FIONS 1 ROAD SPACE, De Juwer, C. ti\stronomicntl Inst., Ltrec ht). fb arth Extraterr. ser; 1: No. 8, 249-50(Nov 1971), The symposium held a Seattle in June 1971 was onvened to review and compare vresent-day pos storittes of hiph oguilar resolution obscrvaticns of tye celeste: bodies, frond the yrouncd, from balloons, and trom spaces and ta have a prestow of future projects, both (he agrcec oes and those stil in the planning stage. (W.D.ML) 9926 XENON RECORD OF FXTINGCT RADIONCTIVITIES IN THE EARTH. Boulos, Mervet 5.; Manuel. Oliver KR. (Univ. of Missouri, Rolla) Selence; 175: No, 4016, 1334-6094 Dee LoT)), Analyses of scnon trom well gas rich in carbon dieside reveal a laree esecss of radiogenic senon-12" from tbe deeav of extinet lodin: -129. Smaller excesses obscrved in the heavy \enon rsetepes are from fission. Phese resutts place narrow limits on any age differeree between the Barth and the cide st meteorites. Phe occurrence of CXee ss Padiogente Seron- 129 in well gas also sugzests that any quantitative de paussine of esasting solid materials to form the atmosp.cre must hase Deon brntd ty avery earl, period at the Barth's hisvtors, approsumatel. che firse 1Q0 sears Vbternatively, ‘his obs rvation is consistent aith a model of tne darth's continuous, | mation it stl] sneomplete, (auth) Sfassing since its tune of fur 9937 fsO PORIC COMPOSITION OF PERAPPLD HELIUM AND NEON IN CARBONACLOUS CHONDREPES, Srinivasan, Bos Manuel, O. kh. «inv. of Missour, Kola}. Barth Planet, sei. Lett,; 12: Neo. 3, 262-6(Nov 1071). The covariais «© observed in Peas topic Composition of prtmoicial He, Se, and Ar in carbonaceous chondrites can be ¢xplamned on the fase et simple Prassceemende rt (eae remacten. fa tt 9938 Ne SND Kr \NALYS bo OF SHUCAPE INCL STONS PROM TRON METROR(ITRS. Pogard, f. ht Himekes ) Got Bornett os. Woesserbure., Gof (Californ sonst. of Tech . Po-adena). Ceochim Cosme fur. vefires No le. 1231-44 (bee 1971) Ihe Ne and Ki Contents of sileate inclusions trom the ‘ron meteorites Copiapo, Fece Cormers, finw ood, Pine Piser, Weeheroo station, and Woodbene © © Ne 3 te 10, fist pty Pade de toms gp, Kr - 2) are comparable to chendritie values. The .sotopig cotopositions ~how crapped pas of both cnondritiy compesitian (ominant ir Ping River); ind atmo spheric compass ion tioinimantan Linwood) Farge spallation eiteets ¢ TK, 5 } ln, Ne, Pour Cormucrs. diter trom the 2 La atom 2) oce.voin Weencvoo otatton and ihe pallahon Meoand Kr espeetra im Wee ke poo oe ceported for ston retearites. A re-iiily sis of litcrature data shows that systematic variations also exist among stone meteorite spallation -nectra which van Le jualitalively end estood in terms of target clement abundance and snielding variations. Very large neutron capture ctfeets on Br Kr Kr = 190/273 » and Pocenr in several metcurites | Rr 205 vatios from 107 atemoerg in Linwood). The t fr/ "By neatron eaptur. on Br tor Linwood and Cop:ipo are distinet trom ‘hat found in stone metecrives. ALL s tuples hase pron nouneed -‘Ne excesses (3 to 50 18 atom, gz} which apparently indie ste itferenees in toriion ‘times from chondrites of less than about 100 yr; bowever, the presence of trapped 12Ne in sthieates shicn were epclosed in molten P > -Ni and cooled slowly prove that they were not entirely otgassea, thus, some of the Ne eaxcess may also he trapp d. Na disceruble fission Se was observed. Gauth) 9939 PRODUCTION RATE OF “Al FROM TARGET ELE- MENTS IN THE BRUDI RHE IM CHONDRITE. Cressy, Philip J Jr. (Goddard Space Flight Center, Greenbelt, Md.). Geochim. Cosmochim. \eta; $3: No, 12, 1283-96(MNec 1971). An 50-< specimen of the Bruderheim chondrite was subjected (o magnetic and heavy-liquid mincral separation procedures, resulting in a numberof chemically distinct samples. These samples were analvzed for cosmogenic Al by nondestructive gamma -gamma coincidence counting. The observed “Al specific nelivities were correlated with the chemical composition of potential target elements by a weighted least-squares fitting technique. Phe calculated “°\l production rates, in dpm per kilogram of targe: clement, are Al, 1130 + 190; Si, 215 + 31,5, 133 411, Mg, 28 4 30. Produetion rares from Ca and Ni + Fe were estimated tobe 2f and 2.2 dpm ‘kg, respectively, from spallation systematics. Most meteorite classes show a distribution of Cf’ Alo ‘8A. primarily between 0.8U and 1.10 (excluding short-cexposure-ige effects). Phe only cxecprion is the cuerites. Phe five cuerttes with the highest relative 2“ Al aetivitics have only G.77 4 0.03 of their respective calculated activitie?. Two Apollo 12 samples, from mean depths of 15 to 20 cm, have appresimately 0.7% of the “AL activities calculated for their chemicul compositions. depletion in 77\1 in limar samples shielded from solar radiation is in accerd with + reduced cosmic-ray tux near the Earth’s orbit, relative to that experience by most meteorites. The “Al depletion in the cucrites suggests that they spent a greater proportion of their orbital periods near 1 AU thin have most meteorites. The similarity in relative “8At con- tents of the lunar samples and the eucrites may not he a coincidenee. (auth) Stars Reter also to abstracts “069, 10186, 10600, and 11014, STELLAR EVOLUTION AND VARIABLE STARS. 9946 Penny, A. J.; Powell, A. lL. T. (Royal Greenwich Observatory, Hailsham, Eng.), Earth ixtraterr. Sci.; 1: No, &, 229-41(Nov 1971). Summarics of the lectures given at the NATO Advanced Study Institute on Stellar Evolution and Variable Stars held at Ofir, Portugal in 1970 are given. (auth) 9941 POPULATION OF HELIUM TRIPLET STATES IN GASEOUS NEBULAE, Drake, G. W. EF. (Univ. of Windsor, Ont.); Robbins, R. R. Astrophys. J; 171: No.1, 55-6101 Jan 1972), Several authors have found that in plunetarv nebulae the population of helium atoms in the metastable 182s 7S state calculated by halancing the theoretical rates of tormution and destruction 1s one or two orders of magnitude greater than that deauced from measured intensity ratios, The problem was reexaniuned, using spdated atomic data and including additional triplet-depepulation mechanisms. Out of 11 objects studied, nine showed reasonable ugreoement between the two methods of deriving the triplet populations. It was found that in some cases depopulation of the 2 35 state via the 2 3P,—-1'S) transition mav be significant. The re- maining discrepancies are no longer sufficient to require extinetien of 10.830 .A photons upon Just grains, as nas previorsly been suprested. .\ comparison of the present results with radiatnvetransfer calculations suggests that the data puv be interpreted In terms of a ‘space filling’ factor deserting the degree ef nebniar condensation. (auth) 9942 UNUSUAL ABSORPTION FEATURE IN THL FARULTRAVIOLE P SPRCTRUM OF RARLY-TYPL SUPERGIANTS. Codsrnid, &. Bay lechroue, DO. 5.) West, id. Re. (Goddard Space