All Questions
Tagged with white-dwarf star
25 questions
5
votes
1
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137
views
Required temperature for a nova
On the wikipedia page of the nova is said that the CNO cyle, which converts hydrogen into helium, starts on the surface of the white dwarf when the temperature reaches about 20 million K.
My question ...
- 716
6
votes
2
answers
2k
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What are the most up to date, accepted, evolution stages of big stars that end in compact objects or a planetary nebula?
There are numerous charts and diagrams showing the stages of stellar evolution, as:
or
among many more (you can find several after googling a little), for example.
When I studied my B.Sc. on Physics,...
- 201
0
votes
0
answers
97
views
Question about a White Dwarf formula
I have a question regarding the White Dwarf radius formula given on wikipedia, in terms of what units I am supposed to use and what expected values of one variable would be.
https://en.wikipedia.org/...
- 387
14
votes
3
answers
4k
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Why do white dwarfs cool down so slowly?
I read that when white dwarfs do not proceed with nuclear fusion, the heat radiation from it is solely based on heat it retained in the past
But then, it floats in an almost 0 K empty space. So, why ...
- 243
4
votes
2
answers
1k
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How small stars help with planet formation
As I understood, low mass stars in their core go through fusion, but only the fusion of hydrogen happens. When it depletes hydrogen, fusion stops as temperature is still not high enough to support ...
- 315
4
votes
1
answer
1k
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What determines the temperature of a white dwarf?
Can someone please explain what determines the temperature of the white dwarf? Is more massive white dwarf hotter ? Also, is the density of a white dwarf always a constant?
- 503
2
votes
2
answers
189
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What would be the product between the collision of a white dwarf and a main sequence star?
Would this ever happen? If it would, what kind of star/supernova would this create? Does it depend on the mass of the main sequence star?
- 1,306
5
votes
0
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75
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Type Ia supernova by fallback?
Is it possible for a massive star of more than 1.4 solar masses (probably around 3 or more but below the threshold for type II) to collapse into a white dwarf and a planetary nebula, then go supernova ...
- 6,733
1
vote
2
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179
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What does an electron-capture supernova leave behind? A white dwarf, a neutron star or nothing?
Somehow, none of the many articles I've read about the recent discovery of electron-capture supernovae has specifically said what they leave behind as remnants.....
- 5,585
1
vote
1
answer
93
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Is something wrong with my luminosity calculation?
A few million years after a white dwarf forms, its surface temperature reaches $100000\text{K}$, while its radius is $0.01R_\odot$. Would this mean that its luminosity is $\Big(\dfrac{100000}{5778}\...
- 6,733
3
votes
0
answers
55
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Can mass loss via accretion occur on stellar remnants?
We know that normal stars can lose mass to a binary companion. But can this happen to neutron stars and white dwarfs? Let's say a stellar black hole is being orbited by a white dwarf or neutron star. ...
2
votes
0
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115
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What would happen if a neutron star merged with a white dwarf?
We've heard of neutron star mergers and white dwarf mergers. But what would result in a neutron star merging with a white dwarf? Would there be a similar super/kilonova, are there any examples of it, ...
2
votes
1
answer
269
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Would dropping a white dwarf or a "still-hot" stellar core into a large planet or brown dwarf create a star?
In the Wikipedia article about stellar engineering, I found this quote:
In The Saga of the Seven Suns, by Kevin J. Anderson, humans are able to convert gas giant planets into stars through the use of ...
- 6,733
7
votes
1
answer
200
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Exactly how long does it take for the exposed core of a star to cool from its starting temperature (several billion K) to ~50,000 K?
OK, I didn't know how I should word this question. But the basic point is that most white dwarfs that we have classified fall in temperature ranges from ~50,000 K to 6000 K. However, at the end of a ...
- 6,733
3
votes
1
answer
355
views
What is the coolest white dwarf known?
Okay, so in this ArXiv report from 2014, scientists discovered the coolest white dwarf, with a temperature of below 3000 K. However, as this report was from over 6 years ago, I think this information ...
- 6,733
10
votes
1
answer
885
views
The colour of blue dwarf stars
The paper "M dwarfs: planet formation and long term evolution" describes blue dwarf stars, a hypothetical next-stage in the lifespan of red dwarf stars within a certain mass range, after which they ...
- 495
1
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3
answers
307
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Are white dwarfs the ones always absorbing mass from a companion?
It seems to me every time I see stellar remnant binary systems where there is a white dwarf and another star or something, it appears that the white dwarf always pulls mass from the star.
What if the ...
- 1,882
1
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3
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698
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Can life on earth be supported by only a Red Dwarf star or a White Dwarf(state still hot not cooled enough yet)?(Provided it is near to the star)
Can a red dwarf star or a white dwarf have enough energy to support life on earth? How it will change the climate and the seasons of earth if it is our only star? (energy source)(Expecting it to ...
- 950
2
votes
2
answers
2k
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What happens if a white dwarf collides with a star like our sun or a red dwarf?
Would it explode in a supernova or will it form a new star?
4
votes
2
answers
404
views
Origin of terms "white dwarfs" and "red giants"?
Can someone explain my why "white dwarfs" and "red giants" were so named? And maybe that's a silly question but why not in the opposite way?
@EDIT
Is this somehow co-related with Stefan–Boltzmann law?...
- 143
6
votes
3
answers
961
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If a white dwarf collides with a giant star, could it create a TZO?
Thorne–Żytkow objects (TZOs) form from collisions between neutron stars and main sequence or giant stars. Ultimately, the neutron star becomes the "core" of the giant star.
However, could this also ...
- 8,196
1
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2
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288
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How can a low-mass star increase its mass to 1.4 Msun? [closed]
In my astronomy class I learned that a only low-mass stars (< 0.5 Msun) will contract, and then become degenerate, until it is a white dwarf. However, we also learned about the Chandrasekhar limit, ...
- 113
4
votes
1
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617
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How bright can white dwarf stars glow as they accrete matter?
I realize this is kind of general as it would depend on the size of the white dwarf and the rate of accretion. The general idea I got thinking about is what would happen if a white dwarf star - lets ...
- 24.2k
14
votes
2
answers
5k
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How much mass will the Sun have when it becomes a white dwarf?
In 4 billion years, when our Sun sheds all of its outer gas layers and turns into a white dwarf, how much mass will the white dwarf have compared to what the sun has today?
Will the planets still ...
- 2,042
13
votes
2
answers
2k
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How do stellar temperatures vary?
The temperature of the surface of the Sun (photosphere) is between 4500° - 6000° Kelvin. Inside the core, it's around 15.7 million degrees Kelvin.
In other types of stars (neutron stars, white ...
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