21 votes
Accepted

Are stars expected to become dimmer before a supernova?

The connection between the dimming and a putative supernova relies on the interpretation that the decrease in luminosity may be due to circumstellar material, ejected in the years/decades/centuries ...
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  • 33.7k
9 votes
Accepted

What would the effects on or around Earth if Betelgeuse went supernova?

tl;dr - The main measurable effect may be minor climate cooling, but in day-to-day life, the only difference would be that we see a cool, bright explosion in the sky, and eventually, Orion becomes "...
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4 votes

Are any supergiants translucent?

Although I will only tackle one part of the question, I find the following part of a picture from NRAO/AUI/NSF, S. Dagnello, cited from space.com worth sharing: You see the radial structure of ...
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  • 5,284
4 votes
Accepted

How can red supergiants be cooler than dwarfs of the same spectral type?

The HR diagram has many forms. There is no one to one relationship between temperature, colour and spectral type that is true for stars of all surface gravities and metallicities. Spectral type ...
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  • 114k
2 votes

At what distance could a supernova damage the Earth's ozone layer?

I came across your question and figured I would reply to it because doing a project on the subject. Explanations here are draw from the website astronimate.com Would a supernova of Betelgeuse only ...
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  • 21
2 votes

Does the dimming of Betelgeuse present any observational opportunities?

In terms of "easier" - not really. There isn't anything made particularly easier or more optimal to measure. Theoretically, as you mentioned, "space stuff" like tiny planetoids or dust that are very ...
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2 votes
Accepted

How to accurately measure the temperature of red supergiants?

Maybe somebody can help me understanding the following quote intuitively: However, by looking at the ratio of two different but related lines - those of iron - we found the ratio itself related to ...
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  • 13.6k
2 votes

How to accurately measure the temperature of red supergiants?

Stars behave like blackbodys. Not perfect idealized blackbodies, however, the spectrum of a star is close enough to the standard blackbody spectrum. Reason why you can use the Wien's Law to calculate ...
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2 votes

Which star has the highest mass loss rate?

Some very hot and massive stars have strong stellar winds, known spectroscopically as "P Cygni profiles" after the type star. P Cygni 'erupted' in the 17th century to magnitude 3 and is now ...
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2 votes

How can red supergiants be cooler than dwarfs of the same spectral type?

For this, its important to understand how temperature increases in a star. Inside a stellar core, there are two forces that are balancing each other out to keep the star in equilibrium. The core ...
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  • 1,050
1 vote

Are any supergiants translucent?

No mass blob of stellar mass is transparent at any wavelength of interest. Opacities $\kappa_{\nu}$(inverse transparency) as function of wavelength becomes really high and broad band at pressures ...
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1 vote

Which star has the highest mass loss rate?

It is my impression that some sort of supernova is likely to be losing mass at the fastest rate for a short period of time. @fasterthanlight responded to my comment and sugggested that supernovae be ...
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