Is Orion Flat

[johnb]

So when I look at Orion I see the distinctive pattern but of course I see it face on. I'm assuming the core stars that create the pattern are in fact at different distances from us. So how can the distance to each star be calculated and is there a simulation where you can see the formation as a model.

John b

[Ganymede12]

Orion isn't flat. Each star is a different distance from us. Star distances are measured using the Parallax effect. We see the stars position change slightly compared to the background star depending where the Earth is in it's orbit.

Celestia is a 3D model of the observable universe. It's free and should give you what you want.

[ollypenrice]

...but the Great Nebula, though doubtless having field stars in our line of sight before it, is a genuine structure gravitationally and historically linked. The distance to stars can be estimated in various ways depending on how far away they are. Because the Orion Arrm is fairly close a number of methods are possible, I think.

Barnard's Loop, the vast curving nebula embracing more than half of the constellation, seems to have been formed by successive supernovae going off in the M42 and Trapezium area.

So many of the key Orion objects, while not literally flat, are truly related to each other and interacting.

Barnard's Loop; http://ollypenrice.smugmug.com/Photography/Widefield-images-including/ORION-FIN-V3-WEB/1169360248_zJFJG-X3.jpg

Olly

[acey]

So when I look at Orion I see the distinctive pattern but of course I see it face on. I'm assuming the core stars that create the pattern are in fact at different distances from us. So how can the distance to each star be calculated and is there a simulation where you can see the formation as a model.

John b

The only direct way to measure star distance is using parallax: if you look at a nearby object with one eye then the other it appears to shift, and if a star is seen from one end of Earth's orbit then the other it may likewise show a small shift. This only works out to a certain distance (dictated by the accuracy with which the tiny parallax shifts can be measured), otherwise the distance must be estimated in various ways, with much greater uncertainty. For instance assumptions about the type of star and hence its inherent brightness, or else if it's part of a cluster then this can lead to inferences about distance. Some types of star (Cepheid variables) have a pattern of brightness change that is directly related to their luminosity, so their distance can be estimated accurately.

This link has distances to stars in Orion as measured by the Hipparcos satellite (using parallax). The site apparently also has some visualizations of star clusters - but I don't know if it has one for Orion itself.

http://www.astrostudio.org/constellations.php?con=Ori

[acey]

Edit: here's a video that claims to show "Orion in 3D"

And you could always make your own model!

http://allsky.ca/worksheets/Orion%20in%203D.pdf