What lights the horsehead nebula?

Question

Check out this picture :
http://www.noao.edu/image_gallery/images/d4/horsehead.jpg
i think that only "starlight from the background is not enough to make that light show.. maybe i'm wrong... whatever the answer, pls help :). Thank you

Answer 1

The Horsehead Nebula is a place where new stars are being born, formed out of the surrounding gas. Many of those stars are very massive and hot, giving off many times more Ultraviolet radiation than our Sun. Just off screen to the left is one such star -- Alnitak, the leftmost star in Orion's Belt, six times hotter than our Sun. That UV radiation energizes the gasses in the nebula. The gasses absorb that energy and give it off as light. Different types of gas give off different colors of light, and the pinkish-reddish color of most of the nebula is an indicator of hydrogen gas.

The whole process is very much like a fluorescent lamp. Fluorescent lights are filled with some kind of vapor (Mercury, Sodium, Neon) that is energized by electric current. The electrified gasses begin to glow their distinctive colors (Mercury is white, sodium is yellow-orange, neon is deep red) as long as the current is flowing. As long as those very hot stars are shining, the nebula will glow.

The "horse head" shape is not the absence of glowing gas, but rather the presence of a cloud of dark dust that is blocking the glowing gas behind. From another part of the Galaxy, it would look very different.

Hope that helps.

JIM

Answer 2

Th surronding nebula is lighted by nearby stars but the horse-head small part is actually a cloud of dense drak material not cabpable of reflkecting light, so it looks dark against a brighter background... The horse-head itself is dark no light gets through at least as seen from here... It is also called BARNARD 33....

Go to this site:

http://www.seds.org/messier/xtra/ngc/b33.html contents follow...

E. Pickering detected IC 434 photographically in 1889, the Horsehead can be detected on a photo made on January 25, 1900 by Isaac Roberts (Roberts 1902). E.E. Barnard recognized the object in the 1910s.

The first published description of the Horsehead Nebula was given in Barnard (1913), and it was first cataloged by Barnard (1919).

The remarkable Horsehead is a dark globule of dust and non-luminous gas, obscuring the light coming from behind, especially the moderately bright nebula IC 434. It is the most remarkable feature of an interesting region of diffuse nebulae, which belongs to a huge cloud of gas and dust situated 1,600 light years away in the direction of constellation Orion. The bright reflection nebula in the lower left is NGC 2023.

The image in this page was obtained by David Malin with the Anglo-Australian Telescope. This image is copyrighted and may be used for private purpose only. For any other kind of use, including internet mirroring and storing on CD-ROM, please contact the Photo Permissions Department (photo at aaoepp.aao.gov.au) of the Anglo Australian Observatory.

More information on this image (David Malin)

Hubble Space Telescope Observes the Horsehead Nebula (April 2001)
Bill Arnett's Horsehead Nebula photo page and info page.

SIMBAD Data of the Horsehead Nebula B33
Publications on the Horsehead Nebula B33 (NASA ADS)
Observing Reports for Barnard 33 - The Horsehead Nebula (IAAC Netastrocatalog)
References

Barnard, E.E., 1913. Dark Regions in the Sky Suggesting an Obscuration of Light. Astrophysical Journal, Vol. 38, p. 496-501. Here also plates XIX and XXb.
Barnard, E.E., 1919. On the Dark Markings of the Sky - with a Catalogue of 181 Such Objects. Astrophysical Journal, Vol. 49, p. 1-23. (First edition of Barnard's catalogue of dark nebulae)
Roberts, I., 1902. William Herschel's observed Nebulous Regions, 52 in number, compared with Isaac Roberts' photographs of the same Regions, taken simultaneously with the 20-in. reflector and the 5-in. Cooke lens. Monthly Notices of the Royal Astronomical Society, Vol. 63, p.26-34 Has the "discovery photo" of the horsehead. Roberts mentions this dark nebula in his description as "an embayment free from nebulosity dividing it [IC 434] in halves."


Dr. MAXR, Astronomer ta large

Answer 3

Oh but it is. They don't mean starlight from the distant and familiar stars seen in the background but from the stellar factory working inside of those clouds. When you think of that picture in 3-d with the horse's head as in the relative foreground, you can imagine that you are on the dark side and behind it there are glowing stars and protostars, as well as hot glowing gasses behind and inside of it. You see this glow reflected off of dust and atoms on the whisps behind it.

For further understanding you can look at the star in the lower left of the picture. Here is another young star (or perhaps star nursury) You can see the dust surrounding the glowing inside there.

Lovely picture.

Answer 4

that's a great question and I see where you're going with this. I like that guy's answer about the horsey sauce, maybe he's thinking of going to Arby's or something :-)

I think it's similar to the milky way. when you look up at the night sky. there are so many stars there but they're very far away so they just have this "wispy" appearance. the other stars you see in the pic are the stars that are closer to us so they appear very bright.

now, given this, I also think there was a lot of "photoshop"ing going on in this photo to make it look pretty, they probably brought up the light levels & contrast

Answer 5

Happy Hoursey Sauce

Answer 6

I'm not sure. Starlight and glowing stardust from a supernova might be it. Space just has too many mysteries.

Answer 7

The same thing that makes our sky look blue. Light.

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