If I take Arcturus for example, its HipID is 32349 and when i look at the raw Hip_Main.dat, it stays that the star's Spectral is K2IIIp whilst Wikipedia says the star's is KOIII. Why the discrepancy, have I misunderstood the Hip data?

Mu Cephei is M2e Ia, in Hip its m2Ia.

Achernar is B6 Vep whereas in Hip its B3Vp

Zosma for example, matches, I get A4V in the Hip file and it says A4 V in Wiki.

  • $\begingroup$ Why do you think there should be perfect agreement? I suppose there would be if the spectral types you have found from wikipedia were taken from the Hipparcos catalogue! $\endgroup$
    – ProfRob
    Commented Oct 22, 2016 at 15:38
  • $\begingroup$ Spectral classification is not an exact science. People will disagee on the relative importance of different line ratios. If one looks at different parts of the spectrum or at differing resolutions one comes to different conclusions. The p at the end means peculiar and it just means that someone found something odd in the spectrum $\endgroup$
    – eshaya
    Commented Oct 30, 2016 at 22:02
  • $\begingroup$ …and the first classifications were done by a human looking at a spectra and judging—obviously, different people might judge differently. $\endgroup$ Commented Dec 16, 2021 at 22:33


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