Spectral Classification Syntax for Binaries

[Solkar]

for α Cnc one gets from

http://simbad.u-strasbg.fr/simbad/sim-id?Ident=alpha+cancri

a spectral type of
kA7VmF0/2III/IVSr

I don't get behind this special use of "/" - Syntax - what's that that meant to denote?

kA7Vm+F02III xor kA7Vm+F02IVSr?
Anything else?

 

[andrew s 1905]

I think the / is intended to separate the spectral class of the components but this one looks strange. If you look up the star here http://vizier.u-strasbg.fr/viz-bin/VizieR?-source=B/mk you will see a range of classifications.
You can follow the links to the papers the last reference has it as Am (A5/A9/F0) in the body of the paper.
I tried to follow the link to your clasification but you had to pay for access.
Regards Andrew

 

[Solkar]

I think the / is intended to separate the spectral class of the components but this one looks strange.

Yes, of course. It's generally used both for separating alternative subclasses and luminosities - "alternative" here as opposed to "between" (that would be "-").

Here however it's unclear, especially because the "A" and" "F" classification are given en suite without such any seperator.

But talking about it - maybe the tail means

one of (F0III, F2III, F0IVSr, F2IVSr)

?

What however combining "A" and "F" without a separator shall denote ... well...

 

[andrew s 1905]

I think your only option is to look up the reference if you want to clarify the meaning.
Regards Andrew

 

[Solkar]

I think your only option is to look up the reference if you want to clarify the meaning.

Yep, So more precisely, I think the only option for me is to an accessible version of the doc ...

And indeed! There indeed is one:

[RA91] Rao, S. S. & Abhyankar, K. MK morphological study of Am stars at 66 Å/mm. Journal of Astrophysics and Astronomy, Springer, 1991, 12, 133-178. doi:10.1.1.489.5030 http://citeseerx.ist.psu.edu/viewdoc/download?doi=10.1.1.489.5030&rep=rep1&type=pdf

So by [RA91] Table. 3, Simbad's encoding

"kA7VmF0/2III/IVSr" means:

K line: A7 V
m (i.e m 39) line: F0 III
m (i.e. m 43) line: F2 III/IV

and Sr line present.

So the "/" operator binds and only binds to the rightmost class ("F") or subclass ("0", "2") token to its left.

And it's nothing about "Binaries".

 

[stefan r]

kA7VmF0/2III/IV Sr

I am not an astronomer. Would like a better answer.

k Spectra with interstellar absorption features
A7 Main sequence star spectral class A7
V luminosity class five

m Enhanced metal feature
F0/2 spectral classes F0 and F2
III/IV luminosity class III/IV
Sr Strontium

This could mean the strontium emission line has a signal strength equivalent to a star with luminosity class III/IV. Emission line spectra contain more than one peak so you could measure more than one spectral class. Would look purple than an A7 should look.

 

[andrew s 1905]

Would like a better answer.

Then I would propose you read the paper Solkar gave the link to.

Regards Andrew

 

[stefan r]

Then I would propose you read the paper Solkar gave the link to.

Regards Andrew

I did that before commenting.