Starship Asterisk*

Rigel and the Witch Head Nebula

Explanation: Double, double toil and trouble; Fire burn, and cauldron bubble -- maybe Macbeth should have consulted the Witch Head Nebula. This suggestively shaped reflection nebula on the lower left is associated with the bright star Rigel, to its right, in the constellation Orion. More formally known as IC 2118, the Witch Head Nebula glows primarily by light reflected from Rigel. Fine dust in the nebula reflects the light. Pictured above, the blue color of the Witch Head Nebula and of the dust surrounding Rigel is caused not only by Rigel's blue color but because the dust grains reflect blue light more efficiently than red. The same physical process causes Earth's daytime sky to appear blue, although the scatterers in Earth's atmosphere are molecules of nitrogen and oxygen. Rigel, the Witch Head Nebula, and gas and dust that surrounds them lie about 800 light-years away.

Sorry neufer, your plans for using an image hosted by tripod are foiled today.

Looks like its my turn to say, "Hey star, nice name!"

At lease the Properties will allow you to drag out the HTTP address
http://pacek.tripod.com/WHSpage/man_in_the_moon1.gif
and see the image

Or re-upload to a real image hosting service.

Thanks to everyone for all the help.


Computer generated image of Rigel compared to the Sun (to scale)

neufer wrote:Thanks to everyone for all the help.


Computer generated image of Rigel compared to the Sun (to scale)

How was the diameter of Rigel measured at 800 ly distance? Anyway, your computer-generated image makes the Sun look about the size of the Earth relative to the Sun! Also, how is the size of Rigel compared with that of Betelgeuse, a red supergiant?

GaryR

Gary, if you scroll to the bottom of this page there is an illustration with Sol, Rigel, and Betelgeuse.
http://www.co-intelligence.org/newslett ... isons.html

Someone ought to do a better illustration. Somewhere along the line that one just got really poorly compressed. And actually I checked wikipedia and the relative sizes of the stars on that image seem to be wrong. Hmm.

I guess star radius guesses change a lot because there's a lot of contradictions even within Wikipedia. For instance, for Deneb the caption to the picture says Deneb is 200-300 times the radius of the sun while the chart on the right claims it is 108-114 times the sun's radius.

An impressive image of that huge yet tenuous dust cloud.

I love how far amateur astrophotography has come.

-Noel