<prompt> Bheka isigaba esingezansi bese uphendula umbuzo emva kwalokho ngolimi olufanayo nesigaba: I-Passage: I-metallicity ephansi ngokungavamile kaVega iyenza ibe inkanyezi ebuthakathaka yeLambda Boötis. Nokho, isizathu sokuba khona kwezinkanyezi ezinjengezi eziyingqayizivele ngokwamakhemikhali, ezisezingeni le-A0-F0 asikacaci. Okunye okungase kwenzeke ukuthi lokhu kuhlukahluka kwamakhemikhali kungase kubangelwe ukusabalala noma ukulahleka kwesisindo, nakuba amamodeli ezinkanyezi ebonisa ukuthi lokhu ngokuvamile kwenzeka kuphela ngasekupheleni kwesikhathi sokuphila senkanyezi eshisa i-hydrogen. Okunye okungenzeka ukuthi le nkanyezi yakheka emkhathini wezinkanyezi ogcwele igesi nothuli olwalunensimbi encane ngokungavamile. Isilinganiso se-helium ne-hydrogen esibonwe eVega singu-0.030 0.005, okucishe kube ngu-40 ngaphansi kweLanga. Lokhu kungase kubangelwe ukunyamalala kwendawo yokuthutha i-helium eduze komhlaba. Kunalokho, ukudluliswa kwamandla kwenziwa ngenqubo yokukhanyisa, okungase kubangele ukungajwayelekile kokuningi ngokusakazeka. Umbuzo: Uhlobo luni lwenkanyezi iManda Bootis?  <response>: obuthakathaka 