No implementation found for style `nprop11' The ctio98b.final.aux file was not found, so sections will not be numbered and cross-references will be shown as icons. No number for "TheradialdistributionofstarsbrighterthanV=15nearOri.PMSstars(solidhistogram)showaclusteringtowardsOri,whiletheotherstars(dasheddistribution)donot.Theprobabilitythatthetwosamplesaredrawnfromthesameparentdistributionis0.0003.Thelinesarelinearleast-squaresfitstothedistribution.Thelackofstarswithin3arcminofOriisanartifactoftheglarefromtheV=3.8star." No number for "Theobservedcolor-magnitudediagramforstarswith12;SPMlt;V;SPMlt;19in0.15sq.degwithin15arcminofOrionis.Spectroscopically-identifiedlowmasspre-mainsequencestars,markedwithsolidcircles,definethePMSlocus.PhotometricPMScandidatesareindicatedbytheopencircles.Thesedataarenotcorrectedforextinction;thereddeningvectorparallelsthePMSlocus.WehaveextendedtheCMDtoV=23,andfindthatthePMSlocusextendstotheH-burninglimit.Wehaveidentifiedoveradozenbrowndwarfcandidatesinthisfield."