AKARI Observations of Circumstellar Dust in the Globular Clusters NGC 104 and NGC 362

[摘要] WereportonpreliminaryresultsofAKARIobservationsoftwoglobularclusters,NGC104andNGC362.Imagingdatacoveringareasofabout10$$imes$$10arcmin$$^2$$centeredonthetwoclusterswereobtainedwiththeInfraredCamera(IRC)at2.4,3.2,4.1,7.0,9.0,11.0,15.0,18.0,and24.0$$mu$$m.WeusedIRC11.0$$mu$$mto2 MASS$$K_s$$2$$mu$$mflux-densityratio($$F_{11}$$/$$F_{2}$$)andIRC24.0$$mu$$mto7.0$$mu$$mflux-densityratio($$F_{24}$$/$$F_{7}$$)asdiagnosticsofcircumstellardustemission.Dustemissionsaremainlydetectedfromvariablestars,obviouslyontheasymptoticgiantbranch,butsomevariablestarsthatresidebelowthetipofthefirst-ascendinggiantbranchalsoshowdustemissions.Wefoundeightredsourceswiththe$$F_{24}$$/$$F_{7}$$ratiobeinggreaterthanunityinNGC362.Sixoutoftheeighthaveno2 MASScounterparts.However,wefoundnosuchsourceinNGC104.

[学科分类] 天文学(综合)

[关键词] "clusters: individual (NGC 104;NGC 362)";"Galaxy: globular";"infrared: stars";"stars: AGB and post-AGB"