<p>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?</p>

<p>Mu Cephei is M2e Ia, in Hip its m2Ia.</p>

<p>Achernar is B6 Vep whereas in Hip its B3Vp</p>

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

CC BY-SA 3.0
2016-10-22T15:38:06.157Z
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!
ProfRob
CC BY-SA 3.0
2016-10-30T22:02:17.477Z
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
eshaya
CC BY-SA 4.0
2021-12-16T22:33:50.980Z
…and the first classifications were done by a human looking at a spectra and judging—obviously, different people might judge differently.
Pierre Paquette
<star><hipparcos>
Have I misunderstood Hipparcos Data with Arcturus?
MiscellaneousUser
# Have I misunderstood Hipparcos Data with Arcturus?

(Asked by: username_0 on 2016-10-22)

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.

**Tags:** star, hipparcos

> **Comments:**
> **username_1**: 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!  
> **username_2**: 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  
> **username_3**: …and the first classifications were done by a human looking at a spectra and judging—obviously, different people might judge differently.  

---

## 0 answers

