Questions tagged [nebulae]

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Solving coupled integral + differential equations for ionoization and combination of gases near a star

The following set of coupled differential + integral equations appear regularly in the literature (e.g Osterbrock, "Astrophysics of Gaseous Nebulae and Active Galactic Nebulae"): $ n_H(r) \int_{\...
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2answers
63 views

What conditions provide the oldest star?

If we define the start of the lifetime the protostar and the end of the lifetime a red giant (at max volume), what conditions would make this time the longest when the star was first formed and ...
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2answers
61 views

Dark Matter Stars Triggering Nebula Collapse

I'm interested in theories of dark matter where dark matter is an equivalent copy (or copies) of ordinary matter. Each equivalent sector is hidden from the others would see the others as 'dark' and ...
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0answers
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Analytical models for planetary nebula expantion

I'm doing an astrophysics project where we measure the properties of a planetary nebula (NGC 7662) where we need to determine it's electronic temperature, electronic density and expansion speed. I'm ...
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1answer
394 views

What is wrong with our Cloud chamber setup?

A nearly identical question has been asked before on this topic, but that thread did not help us any further. Me and a classmate built a cloud chamber in order to see elementairy particles (we aren't ...
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1answer
56 views

Nebulas and Ideal Gas Equation confusion

I was wondering how stars form and watched this video: https://youtu.be/mkktE_fs4NA?t=18s The lady says: "Gravity brings matter together. And when you bring matter together, when you squeeze ...
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1answer
194 views

Would an HI or HII region have a color?

That is, if we were approaching an HI or HII region in a spaceship, would the cloud have a color visible to the naked eye? Of the HI region, Wikipedia says: These regions do not emit detectable ...
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1answer
468 views

Angular momentum, its conservation and Nebula theory

I am carrying out a research work and I am stuck at the first page where there is an introduction to the angular momentum and its relationship in the formation of the solar system. According to that ...
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0answers
136 views

If entropy is positive, then why do stars form from nebulae?

Sorry if I have so many misconceptions with this questions, but I guess that's the point of asking questions. If entropy, the measure of disorder, is always positive, then how come a star could form ...
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2answers
684 views

Why isn't all of the dust in a nebula used in the formation of a star?

I was watching a show on discovery and according to it, in a nebula the dust and gases slowly come together and as the gravity increases and the pressure rises in the core the gases fuse together and ...
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1answer
139 views

Could a bipolar nebula be produced by a time gradient?

M2-9 is an example of a bipolar nebula that resembles two back-to-back rocket nozzles. Is it possible that this shape (somewhat unusual for an explosion) is the result of a time gradient? A rotating ...
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2answers
99 views

Distinguishing Gamma-rays and stars from each other in nebulas

How do you tell the difference between a gamma-ray burst and a star just from a picture of a nebula, in which it cannot flash on and off here and there?
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4answers
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Names, maps for Milky Way dust clouds? (Dark Cloud Constellations)

There is a nice image of the Milky Way, labeled with constellations, at 360°x45° panorama with constellations: It leads me to wonder how much we know about the Great Rift, Coalsack and other ...
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1answer
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How are new nebulae being created?

The nebulae we see in the night sky are forming new stars. The stars are eating up the nebulae and there is no obvious process in which those nebulae are being created to compensate for that. ...
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2answers
9k views

How dense are nebulae?

How functionaly dense are nebulae? Are they so sparse they are only visible from an interstellar or intergalactic perspective or would you be unable to see your hand in one? Do they vary widely in ...