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10 votes
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What are those stars that cross the galactic center?

Nice question and interesting data! Going through the references of the linked site, one gets a more verbose description of the video: After more than 1,000 nights of observations spread over 15 ...
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6 votes

Reason for different surface temperatures of Tau Ceti and Epsilon Indi at similar properties

Metallicity (or the fraction of things other than Hydrogen or helium) If you look on the Wikipedia page it points out that Tau ceti is metal deficient ([Fe/H] = -0.55) and Epsilon Indi has [Fe/H] = -0....
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5 votes
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How many stars can we resolve?

I tried to get a estimate for an upper-bound with currently deployed instruments. Assuming that, resolution-wise, the James Webb Space Telescope is the best telescope we have today, I looked into its ...
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4 votes

What kinds of stars have viable habitable zones other than G-type stars, and what would life be like orbiting them?

Part One: Habitable Zones. All stars have habitable zones around them, hollow spheres between where a planet would receive too much energy from the star and become too hot for liquid surface water. ...
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4 votes

How to calculate metallicity of a star that is made of iron of 20kg and Hydrogen 1000 kg?

You cannot calculate the solar ration of $\mathrm{Fe/H}$ nor can you calculate the logarithmic ratio of iron to hydrogen for a star - both are entities you have to measure. So in order to calculate ...
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4 votes
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Stellar evolution temperature gradient - why the logarithm?

This expression comes from considering a volume element of gas inside a star in hydrostatic equilibrium. If the pressure changes, the gas is compressed or expanded, and the volume element moves a ...
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4 votes
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How can the upper limit for a star's mass be calculated?

A basic argument would go something like this: If you assume that the opacity in the star's envelope is dominated by Thomson scattering from free electrons, then it is simple enough to show (e.g. see ...
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3 votes
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How do I phase fold the light curve for a variable star?

"Phase folding" is just a procedure whereby you replace the time-axis values by t % P, where P is the period and % is the modulo operator that returns the remainder of t/P. There are are a ...
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1 vote
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What can we learn from the rotation data of a star?

The question is too broad to provide extensive detail. The rotation rate of a star can determine a star's lifetime on the main sequence. Rotation drives mixing that can draw new fuel into the fusion ...
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