sigma Orion - an enigma ?! - (solved in October,29)

[jsmoraes]

My last capture shows Sigma Orion star. Wikpedia says it is a system of five stars. But I saw seven stars, despite of bad focus. Searching in Aladin Sky Map it seems to be 3 stars together Sigma, and 2 stars together D or E, really I don't know which of them. Therefore it should be 7 stars. Searching in Sky-Map I only saw 2 stars in Sigma's region and I saw 2 stars together D or E, too.

My question: Sigma Orion is a 5, 6 or 7 stars system ?

[Larryp]

Good capture, Jorge!:)

[billdan]

Looks like 7 to me
Bill

[mithrandir]

Jorge,

Vizier says there are 5 stars within 1 arcmin of the coords of Sigma Ori (see I/274/ccdm) - CCDM 05387-0236 A/B/C/D/E.

CCDM 05386-0234 A/B/C/D are the group at about PA 45.

The Aladin image agrees with your photo.

[jsmoraes]

Would be 5 stars with gravitational interaction and the others 2 stars don't belong the system, being only visual appearence ?

One seems to be very close Sigma Star! And the other seems to be side by side ! :question:

[jsmoraes]

I know is out of topic, and ok to me if it has to be tranfered to another place of forum, but ...

:question: And, now, worse to me !

Sigma Orionis seems to be a cluster, with numerous low mass stars, brown dwarf, with mass only a few times that Jupiter.

http://stars.astro.illinois.edu/sow/sigmaori.html

Or

Herschel describes as two groups of 3 stars. Barlow, as two groups of 4 stars, adding two little stars to each group of Herschel.

Main stars:

component A, mag 4 with a a little mag 11 star

component B, mag 8

Note: It seems my photo shows these 3 stars.

component C, mag 7

component D, mag 8,5 with a little mag 12 ( more distant from A)

Note: My photo shows two stars with same magnitude, side by side, and near other star (what are their names ?). :confused2:

component E, mag 9

http://www.cosmovisions.com/ori.htm

:confuse3:

[mithrandir]

Jorge, since you haven't marked which stars you mean does this help with identification? I have a version using the Tycho2 catalog but GSC2 puts labels on many more objects.

[jsmoraes]

Thanks Laurie, Bill and Andrew. I was thinking about stars D and E.

S1MH000460 should be A an B and little star mag 11. To me it seems there are 3 stars in my photo.

S1NG000452 should be C.

And who is D and E ? S1MH000425 (two stars) and S1MH000415 ?

Or D should be S1MH000384 (star at top of image) ? Perhaps S1MH000350 ?

Many texts tell about 5 stars (A,B,C,D and E) but none shows who is who.
The reference most distant is relative. And the description of distance with arcseg wasn't clear to me. :ashamed:

[jsmoraes]

Ok , I did a great confusion! With my GSO 305 mm and Canon 350 D the resolution don't permit the separation A and B. So, the system is too more together then I thought to be. :ashamed:

I received a photo with correct identification.

Ufa ! At least, there isn't nothing wrong in the sky. But, with me ... Attention, Jorge! Wake up, man ! :screwy: