Questions tagged [stars]

Stars are astronomical bodies that are (usually) mainly composed of Hydrogen, Helium, and Lithium. They are massive enough that their gravity compresses the matter to the point where nuclear fusion occurs, which creates a lot of heat and tends to make stars output radiation along a blackbody curve. Typically the radiative output is significant in the visible spectrum making stars very bright objects.

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11
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2answers
766 views

Where does a star's angular momentum go as its spin slows down?

So we know that stars slow down as they age. But total angular momentum must be conserved. Where does that angular momentum go? The dissipation of Earth's tides somehow transfers Earth's angular ...
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What's the difference between a red giant and a red supergiant?

I've seen both theoretical and observational definitions of stars. For example, an AGB star is a star where two sets of nuclear reactions (helium to carbon and hydrogen to helium) are taking place in ...
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Is Jupiter a failed star?

In my physics lessons, my teachers have always been keen to tell my class that Jupiter is considered a 'failed star' by scientists. Is this true? In my own effort I wondered if maybe this could just ...
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“Blue Bumper” Stars

I was recently overviewing various massive compact halo object studies (the Anglo-Australian MACHO collaboration and the French I/II EROS collaboration), and they frequently reference "blue bumper ...
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1answer
159 views

How are new nebulae being created?

The nebulae we see in the night sky are forming new stars. The stars are eating up the nebulae and there is no obvious process in which those nebulae are being created to compensate for that. ...
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Metal Dilemma: Only very few civilizations per galaxy

This is a question in the area of extraterrestrial life. While life may be possible without it, space travel is probably impossible without metal. Metal is created in stars and heavy metals (above ...
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Solar system, visible stars and deep sky objects

Since I've seen that galaxies are often called "deep sky objects", as opposed to individual stars, does this mean that all visible stars in the night sky actually only belong to The Milky Way Galaxy? ...
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How can a Population III star be so massive?

How can a Population III star have a mass of several hundred solar masses? Normally the limit is about 100 solar masses.
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What elements can be created in the fusion process of different types of stars?

As I understand it fusion inside a sun can produce heavier and heavier elements until some sort of "nucleus size limit" is reached. As far as I understand, the limit is thought to be reached with the ...
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Color Variation in RR Lyrae

I've been doing some research on RR Lyrae stars and haven't been really able to find an answer to this question. RR Lyrae are well known for their periodic magnitude, and also are usually found in ...
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3answers
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Significance of letters in Hertzsprung-Russell (H-R) diagram

The Hertzsprung-Russell diagram that categorizes star types uses the letter codes O, B, A, F, G, K, and M to indicate a star's temperature/color. Hottest (blue) is O and coolest (red) is M. What do ...
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Is a rogue 'exoplanet' classed as a exoplanet?

Given that the term planet strictly (according to the IAU) refers to a body around the sun, rogue planets can't be called that, so I assume they must be called rogue exoplanets? But do they even ...
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How would two equally massed stars orbit?

In an empty universe, except for two equally massed stars, how would they orbit? Or, for another example, if the earth suddenly grew to be the mass of the sun, how would they orbit, or interact? Would ...
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How are newly discovered objects (stars, planets, galaxies…) named?

When a new astronomical object (star, planet, galaxy, comet, etc.) is discovered, what is the official procedure to name it? Who decides about the name of it? Can they be changed in time? Extra ...
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Calculations of apparent magnitude

I was attempting to do some calculations of apparent magnitude to help solidify my understanding of the topic, but have been running into some confusion. According to Wikipedia, the apparent ...
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Binary stars' apparent magnitude

If you plot the apparent magnitude of a binary system (so you are unable to see 2 distinct stars) against time, it gives a repeating 'M' effect. (from http://accessscience.com/) Assuming one star is ...
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What is the probability that a star of a given spectral type will have planets?

There is a lot of new data from the various extrasolar planet projects including NASA's Kepler mission on extra-solar planets. Based on our current data what is the probability that a star of each of ...
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How many stars are in the Milky Way galaxy, and how can we determine this?

I have heard multiple estimates on the quantity of stars within our galaxy, anything from 100 to 400 billion of them. The estimates seem to be increasing for the time being. What are the main methods ...
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277 views

Gyrochronology, the formula is empirical ?

The formula used in Gyrochronology that relates a star's Period of Rotation-Mass-Age is empirical? This news How to Learn a Star’s True Age "“A star’s rotation slows down steadily with time, ...
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What happens if a black hole sucks up a massive amount of oxygen and hydrogen?

Suppose a black hole were to suck up a massive amount of surrounding oxygen and hydrogen. Would this ignite inside the black hole and turn it back into a star?