I can memorise the spectral classes (OBAFGKM) but how much of the information do we need? I can draw a H-R diagram comparing it to absolute magnitude but how about the colours, temperatures, etc? Is it common to be asked about which class a star might belong to based on intrinsic colour or surface temperature? If so, how much flexibility is there in the marking? Must it be an exact answer, or roughly the right class? (I.E, confusing 'B' for 'O')
In the specification there is a table with spectral class, colour, temperature range and prominent absorption lines. In the 2 most recent papers it hasn't asked for anything specific but if it's in the specification they could test us on it.
Ive learnt the whole table- as it is one of the specification points. Problem is as theres only been 2 papers we dont know if this is something they wont test us on as they havent before, or something thats likely to come up as it hasnt yet!