Questions tagged [opacity]

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How do I code the formula for the minimum mass of a stellar fragment from Whitworth & Stamatellos, 2006?

I was researching the formation of brown dwarfs, and I stumbled into the paper "The minimum mass for star formation, and the origin of binary brown dwarfs", and I am attempting to code a ...
2 votes
0 answers

"Opacity" in red dwarfs

One day, while researching on blue dwarfs in Wikipedia, I stumbled across something that I cannot understand: Rather than expanding, however, red dwarfs with less than 0.25 solar masses are predicted ...
8 votes
1 answer

Why does metallicity increase the opacity inside stars?

A vague answer I've seen is that it has something do with a greater number of possible excited states, but I don't know what this means for a partially ionized plasma - much less a fully ionized ...
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1 vote
1 answer

What is the meaning of grain opacity and why does it affect the formation time of gas giants?

While doing research for my presentation on the formation of gas giants, more specifically the "core-accretion model", I have been stumbling across the term "grain opacity" and don'...
6 votes
2 answers

Are any supergiants translucent?

Are any supergiants translucent? Some have volumes thousands of times more than the Sun's while having maybe twenty times the mass of the Sun which makes them sound rather diffuse. If there was a very ...
5 votes
1 answer

What class of elements are providing the many electrons needed to make the H- ion?

Continuous absorption by the H- ion reaches its maximum in the cool atmospheric layers of G stars. At these temperatures, most of the hydrogen atoms are neutral; but what class of elements is ...
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71 votes
2 answers

Is it dark inside the Sun?

This might sound like a strange question, but something got me thinking about it recently. The opacity of plasma in stellar interiors can get quite high, making for shorter free-paths for photons. In ...
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6 votes
2 answers

How far can you see in solar plasma at just under 1 solar radius?

I was trying to compose an answer to this question here, about touching the surface of a star, and I was going to mention that the popular depiction of the sun's surface as 'basically lava' (as ...
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2 votes
1 answer

What leads to increase in opacity in kappa mechanism?

I understand that the kappa mechanism (that leads to star variability) causes an increase of opacity with increasing temperature in partial ionization zones. However, I'm not sure I understand what ...
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3 votes
1 answer

What is the main source of opacity in sunspots?

In the first version of my answer to Are sunspots vertically displaced from the surrounding photospheric plasma?, I naively used Kramer's law to attempt to show an inverse relationship between opacity ...
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