All Questions
15 questions
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Star forming regions
Some star forming regions, like Bok globules (which contain stars that still haven't dispersed their molecular hydrogen and cosmic dust shell) appear dark compared to the rest of the H II in which ...
- 716
1
vote
1
answer
93
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What was the first nebulae of the first class?
On Wikipedia, it describes the Tarantula nebula as
the second of the "Nebulae of the First Class",
Wikipedia says that a Nebulae of the First Class is a Nebula with no other stars visible ...
- 1,097
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2
answers
1k
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Why does Helix Nebula look like an eye?
The infrared lights, the material clumps that radiate and the whole view resembling a celestial firework or giant eye
- 53
7
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2
answers
1k
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What kind of nebula was the Sun formed from?
I was just wondering what type of nebula did the Sun form from because mainly there are 5 categories: emission nebulae, reflection nebulae, dark nebulae, planetary nebulae, and supernova remnants, so ...
user47732
11
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1
answer
2k
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What is the bright orange star?
After reading this NASA article on Tarantula's Nebula of this image:
What is the really bright orange star in the center or upper-left of the young blue stars? The second link further provides ...
- 2,115
25
votes
4
answers
3k
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How else can a star form, other than gravitational collapse?
I read this paragraph on the Sun's page on Wikipedia:
[The Sun] formed approximately 4.6 billion years ago from the gravitational collapse of matter within a region of a large molecular cloud. Most ...
- 251
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votes
1
answer
250
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What does the Reddening line represents in this U-B vs B-V plot?
The plot is from this paper (pg-8).
They have also talked(in the same paper) about how central stars from galactic longitude range $20^\circ-80^\circ$ will have a very unusual Reddening line (pg-9). ...
- 3
4
votes
1
answer
71
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Long-lived supernova remnants?
We cannot see the supernova remnant of the star that triggered the formation of the Sun and the Solar System, as the remnant dispersed and became mixed into the interstellar medium. So I am wondering, ...
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3
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1
answer
220
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Are the bright dots in this image individual stars?
I saw this picture of M51 (Whirlpool galaxy) and noticed many, many bright dots around and in the galaxy. I have freehand-circled a few as examples. Are these individual stars (probably supergiants) ...
3
votes
1
answer
161
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The star that died and became the Crab Nebula and Crab Pulsar?
The supernova of this star was witnessed about 1 thousand years ago, and the star's remains are the Crab Nebula and Crab Pulsar. What is this no longer existent star called? How massive was this star? ...
- 31
2
votes
1
answer
2k
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Why do stars rotate slower than they're expected to?
Due to conservation of angular momentum, I thought most stars would be spinning extremely fast because they have a relatively small diameter. However, it turns out that this is not true and most stars ...
- 31
1
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1
answer
759
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What factors makes a star big in size(Physically)?Is the size of the nebula a relevant factor?
(Our sun compared to some of the known stars)
I know that the star is born in a nebula.Do only a extremely gigantic nebula give rise to large-radius star or is there any other factors related?
- 950
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2
answers
1k
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Will new stars stop forming at some point of time?
New stars keep forming in the universe thanks to all the nebulae. Now, we need Hydrogen to form stars and there would a time when all the hydrogen will get exhausted, and no more star formation will ...
- 547
31
votes
2
answers
38k
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How many stars and galaxies can be seen by the naked eye?
How many of the luminous dots that we see naked are galaxies and not stars from our galaxy?
I imagine that the majority of the luminous points that we see naked eye during the night, are actually ...
- 617
5
votes
1
answer
108
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Why is there billowing dust in nebulae?
Why do some nebulae look like the billowing clouds? Wouldn't that require something like a viscosity in empty space?
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