Celestia Forums

I decided to do a matching of the stars listed in the HabCat to spectral types in the stars.dat database.

A couple of things that I noticed - firstly there are a lot of stars which are assigned unknown spectral type, these stars also do not seem to have spectral types listed on SIMBAD.

Then I got to HIP 26380, spectral type WN.

This struck me as being somewhat suspicious given that as far as I know Wolf-Rayet stars are highly unstable and short-lived.

SIMBAD gives the spectral type as G0V/G1V.

EDIT: The HabCat file gives the B-V colour index, would this help in assigning spectral types to the stars where spectral type is not listed?

Hipparcos gives the spectrum as WN.
B-V is also listed in Hipparcos, but the listed value of 0.58 for Hip 26380 is consistent with a ~WN5 Wolf-Rayet or a ~G0V main sequence star.
So I guess you have to chase down the spectrum Simbad quotes and decide whether you believe it more than Hipparcos ...

In general, though, the combination of absolute magnitude and B-V would let us have a more realistic stab at assigning spectral classes to stars where the data are otherwise absent from Hipparcos. Chris would need to rebuild stars.dat from the bottom up for that to be implemented, however.

Grant

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