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Questions tagged [variable-star]

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What are these data in light curve generator

I'm generating light curves for some variable stars on the AAVSO website (see https://www.aavso.org/lcg ) . I can choose what type of data must be plotted. Can you explain what they are? Thank you in ...
22
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1answer
2k views

Are stars expected to become dimmer before a supernova?

With the recent news about the "fainting" of Betelgeuse and the speculation that this might be a precursor to a supernova, I'm wondering if there is any theoretical/observational basis for this ...
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0answers
54 views

When we say a variable star is “fainting” does it mean something more or different than “dimming” or “fading”?

A comment below the question Does the current “fainting” of Betelgeuse show any spectral trends that differ from it's normal variability? suggests that "dimming" would be a better term, but I have a ...
4
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0answers
87 views

Does the current “fainting” of Betelgeuse show any spectral trends that differ from it's normal variability?

The Astronomers Telegrams #13341 The Fainting of the Nearby Red Supergiant Betelgeuse and #13365 Updates on the “Fainting” of Betelgeuse (both in December 2019) discuss the importance of measuring ...
1
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0answers
64 views

Why do these photometric observations of Betelgeuse look “quantized” in 0.1 magnitude steps?

The most interesting question related to this Will Kinney tweet would be what's going on with Betelgeuse? but I can't help but wonder why much but not all of the photometric data is clustered in ...
2
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1answer
50 views

Astrophysics of Supernovae - Energy over Distance?

I need this for worldbuilding, but it is a physics question. I want to be able calculate the energy over distance from a hypernova of a variable star like Eta Carinae. Understanding what energy levels ...
3
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1answer
69 views

Brown dwarf magnetic activity

I have not been able to find an answer to my question through google, and therefore ask it on this medium. Do brown dwarfs have spots and faculae similar to other heavier stars?
3
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0answers
24 views

Large amplitude dipole pulsator

Consider a semiregular variable with amplitude of 1.5 mag. Is it possible to explain brightness variations by purely dipole pulsations?
3
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1answer
71 views

What is period doubling in a variable star?

I'm coming across the concept of "period doubling" in RR Lyrae stars. When I look up what period doubling is on the Internet, I find general-level explanations of bifurcations of dynamical systems ...
2
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1answer
106 views

Are stars beyond the asteroid belt less constant?

If we graph the variability of a small bright star which is lined up with the asteroid belt, is it less constant than stars that are far away from the asteroid belt? To what degree does variability ...
0
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1answer
80 views

Stopping down a telescope to reduce brightness by 5 magnitudes

Suppose we have a variable star with a change in magnitude between maximum and minimum of 5 mag. How much would you need to stop down a telescope (block some of the area) so that the star at maximum ...
2
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1answer
119 views

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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2answers
687 views

Do stars vary their own brightness?

All I could find on the internet was about how stars vary in brightness depending on their distance to Earth, temperature, type of star... But my question is, can a star can change its brightness.
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1answer
815 views

How to find a Cepheid's pulsation period using its graph?

Basically, I've been seeing these graphs that say: Cepheid Period-Luminosity Relation and the Period axis is supposed to be "logarithmic"; How does this graph work? Since the luminosity of a star ...
1
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1answer
95 views

Variable Types of Stars

I'm trying to decode the Variable Types of stars in the Hipparcos Library. I see there are a number of stars for example :- EA/AR - Does that mean the star is both a EA(Eclipsing Binary Star) and AR ...