Warrick
  • Member for 7 years, 8 months
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  • Birmingham, UK
What exactly will happen when the Sun leaves the main sequence? I know it expands to a red giant twice, but what happens exactly? What's the timeline?
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5 votes

I've used a research-grade tool to calculate a very simplified and definitely not research-grade run of the evolution of a roughly Sun-like star roughly from birth to its white-dwarf cooling sequence. ...

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Does the transition between total convection and partial convection cause a significant decrease in lifespan?
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5 votes

As already noted in another answer, there aren't many studies about the long-term evolution of low-mass stars because we're fairly sure they don't evolve off the main sequence within the life of the ...

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Could liquid water have existed in open space 15 million years after the Big Bang?
21 votes

As others have mentioned in the comments, there wouldn't have been any oxygen to form water. Soon after the Big Bang, the protons were hot or dense enough to fuse up to helium and some lithium but ...

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How does the stellar evolution for low and intermediate mass stars differ?
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3 votes

Where does the evolution actually stop? Is the Helium Core Flash the last thing a Sun-like stars experiences or does it in fact follow the rest of the tractory? Stars with masses below about 2 solar ...

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Given a star's mass, age, and composition, how do I calculate the rest of its properties?
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4 votes

In astronomy research, models of stars are computed using large software packages that solve a set of differential equations that describe the structure of a star as it evolves, mostly because of ...

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Why are all space observatories in Chile?
8 votes

I write this as a theorist who's never visited a modern observatory, so I will gladly defer to any true observers who do come along. But as far as I know, the best sites for astronomical observatories ...

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What are Thorne-Żytkow objects?
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7 votes

I'll try to add a bit of context to the Wikipedia article, though the major references are all available there. The article covers things like the potential formation mechanisms but I guess doesn't ...

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Python with image in fits format
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4 votes

I personally use Astropy, specifically astropy.io.fits, although I'm not a seasoned user of FITS files and I don't really know their layout. As an example snippet of code, I often load data from FITS ...

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How much of carbon, sodium, silicon, and magnesium does the Sun have?
4 votes

James' answer already covers the fact that since helium was formed in the Big Bang (see Big Bang Nucleosynthesis), stars always formed with some helium (about 1/4 by mass). Those first stars fused the ...

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Relationship between metallicity and color? Should Pop. I stars be blue?
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3 votes

I think the misunderstanding (which I've been asked about before) is because Population II stars are redder as a population, even though for a given mass, a main-sequence Pop II (i.e. metal-poor) star ...

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At what density does helium burning start in a star?
3 votes

Your question inspired me to have a look at the data that is used in plots produced by the stellar evolution code MESA. Here's a $\rho$-$T$ diagram showing boundaries of roughly where various nuclear ...

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Why do post main sequence stars enter the red giants branch?
2 votes

If your question is why the star starts moving up the red giant branch, it's in essence because of the behaviour of the surface opacity and the development of a substantial convective envelope in ...

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Why is the Sun's brightness and radius increasing, but not its temperature?
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5 votes

The effective temperature $T_\mathrm{eff}$ of a star, which is presumably what's been plotted, is defined through its relationship with the star's radius $R$ and luminosity $L$ by $$L=4\pi R^2\sigma ...

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If a white dwarf collides with a giant star, could it create a TZO?
3 votes

If you slam a white dwarf into a main-sequence star or red giant such that the white dwarf becomes the core you'd get... a red giant (or supergiant). Perhaps that sounds odd but basically the cores ...

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How/where to check where the Sun is (constellation)?
1 votes

In this case, Wolfram|Alpha has you covered. For example, look at the result for "which constellation was the Sun in Jan 1 1400". That said, I'm not sure this calculate includes the precession of ...

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Why is the detection of gravitational waves such a "Big" deal?
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10 votes

The way I see it, there are three reasons it's such a big deal. The first, as you say, is the (further) confirmation of Einstein's theory of gravity. Newtonian gravity doesn't have gravitational ...

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How do star densities work?
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5 votes

The mean density of the star is really only defined by the formula $\bar\rho=M/V=3M/4\pi R^3$. The radius of a star is a generally a very complicated function of a star's other properties. When we ...

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Can any stars ever form supermassive black holes?
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6 votes

As you say, making black holes quickly in the early Universe is a major unsolved problem in astrophysics. There are various hypotheses, of which two roughly correspond to supermassive stars. All ...

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Why do certain massive stars leave no remnants?
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8 votes

The gap appears because of pair instability supernovae. In short, as one looks at such massive stellar cores at increasing temperatures, an ever-larger fraction of the photons are sufficiently ...

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Which stars have been named after astronomers?
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2 votes

You probably need someone better versed in the history of astronomy than me, but I'll give it a stab. As you've already noticed, the Wikipedia article on stars named after people has some entries, ...

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Why do stars become red giants?
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11 votes

(This is somewhat simplified but I hope it gets the idea across.) The reactions stop in the core because it runs out of fuel. During the main sequence, the star is supported by the fusion of hydrogen ...

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Conflicting information about the star Delta Pavonis?
1 votes

I haven't looked in too much detail, but the first point is to note that there are two estimates of the age: 6.6–6.9 Gyr and 9.3 Gyr. The latter is given without uncertainties, but I looked it up on ...

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How to get error out of astropy constants
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5 votes

While I'm not familiar with the package, a very quick look at the documentation suggests that you want In [90]: c.M_sun.uncertainty instead. I've just checked and this appears to be correct. > ...

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Where might a semi proficient amateur analyst participate in meaningful astronomical efforts
0 votes

I haven't managed to formulate a coherent single answer, but here are several suggestions for where to find some hints of current topical research where you might be able to contribute. Open source ...

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Why was this asteroid (4864 Nimoy) chosen to be named after Leonard Nimoy?
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2 votes

I'm not entirely sure, but I would guess that it's simply because the discoverer suggested it. After a few steps in the process of characterizing an asteroid's orbit, the discoverer gets to suggest a ...

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Could there be a closer star to Earth than the Alpha Centauri triple star system, excluding the Sun?
3 votes

It's pretty easy to put upper limits on how bright any nearer stars could be. As a rough guide, consider a survey like Hipparcos, which is complete to something like 9th magnitude. If there's another ...

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How to calculate magnitude of a star in a triple star system?
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2 votes

Basically you need to convert between luminosities (which you can add) and magnitudes using $$M-M_\odot=-2.5\log_{10}(L/L_\odot)$$ Let's call the total luminosity $L_0$ and magnitude $M_0$ and the ...

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Do astronomers and astrophysicists more often use diameters or radii when discussing about planets, dwarf planets, exoplanets and stars?
2 votes

Definitely radii, with one notable exception... When observers talk about how large an object is on the sky, they usually discuss angular size, which is related to the diameter of an object, not the ...

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What is the exact mass of the Sun?
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13 votes

The mass of the Sun is determined from Kepler's laws: $$\frac{4\pi^2\times(1\,\mathrm{AU})^3}{G\times(1\,\mathrm{year})^2}$$ Each term in this component contributes to both the value of the solar ...

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Are the stars in constellation located in a plane or they are in different distances
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10 votes

Constellations and asterisms are generally not proximate in space, but rather happen to be nearby only when viewed from Earth. From Wikipedia's article on asterisms: Like constellations, asterisms ...

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