What is the contradiction if a stellar spectrum exhibits both molecular lines and helium lines?

Answer 1

Is this a trick question? Generally speaking helium lines only form at temperatures well above the cooler temperatures where molecular traits

can form (to be displayed spectroscopically). So, the implied contradiction is two opposing thermal conditions - hi temp vs low temp - or two traits, He vs say O2, which require two contradictory temp conditions. Anything else would generally require a rather exotic set of circumstances, as say with a mass ejection having outer coronal propoerties with temps high enough to be burning helium (in a thin shell), but spatially removed near the core of the event things have since cooled and might be showing a few molecular traits - a long slit cross sectional spectrum of the entire area might conceivably yield a merged spectrum showing seemingly contradictory (thermal) traits. Take stars c,d, and d in the Trapezium, for example. Each of these systems contains an O or B primary star with smaller K to M type companions; a long slit application which takes in the whole system may very well (well it will!) show seemingly contradictory traits. It is precisely mixes of such traits which define a spectroscopic binary. Yes?

Have I answered you question? I did the best I could! (laughing)