<prompt> I-Passage: I-metallicity ephansi ngokungajwayelekile yeVega yenza kube yinkanyezi ebuthakathaka yeLambda Boötis. Kodwa-ke, isizathu sokuba khona kwezinkanyezi ezinjenge-spectral class A0-F0 ezingajwayelekile ngokwamakhemikhali asicaci. Okunye okungenzeka ukuthi i-chemical peculiarity ingaba ngumphumela wokusabalalisa noma ukulahleka kwesisindo, yize amamodeli ezinkanyezi akhombisa ukuthi lokhu kuvame ukwenzeka kuphela ngasekupheleni kwesikhathi sokuphila kwe-hydrogen-burning star. Okunye okungenzeka ukuthi inkanyezi yakhiwa kusuka kumphakathi we-interstellar wegesi nothuli owawunensimbi engajwayelekile. Isilinganiso se-helium kuya ku-hydrogen esibonwe eVega ngu-0.030 0.005, okucishe kube ngu-40 ngaphansi kweLanga. Lokhu kungabangelwa ukunyamalala kwendawo yokuhlangana kwe-helium eduze kobuso. Ukudluliswa kwamandla kwenziwa ngenqubo yokukhanyisa, okungadala ukungajwayelekile kokusabalalisa nge-Vega Boötis. Umbuzo: Luhlobo luni lwenkanyezi?  <response>: obuthakathaka 