All Questions
Tagged with star main-sequence
26
questions
7
votes
3
answers
1k
views
When a star enters a red giant phase, does the pressure in its core increase or decrease?
When a star becomes a red giant, does the pressure in its core increase or decrease?
From one side, the only source of pressure in a star is gravity. A red giant is much larger than an ordinary star, ...
- 800
3
votes
1
answer
199
views
Mimimum stellar mass and minimum temperature that triggers hydrogen burning
We can derive the minimum mass of a star in the main sequence using the minimum temperature $T_C$ that triggers hydrogen burning in the core. Then using the stellar structure equations we can derive ...
5
votes
3
answers
995
views
Is it possible for a star cluster to be composed of main sequence stars?
From what I hear about globular clusters, they are primarily composed of very hot giant stars, which are not the most conducive for life as we know it.
Main sequence stars like our own, due to their ...
- 469
2
votes
1
answer
310
views
Does the mass-luminosity relation work for brown dwarfs?
There is a mass-luminosity relationship of the form $L \propto M^a$, where $a = 3.5$, that is is applicable to main-sequence stars. Is there a similar relationship that holds for brown dwarfs?
user47732
9
votes
1
answer
344
views
What does the surface of a star with a radiative envelope look like?
This image from Wikipedia shows that main sequence stars above 1.5 solar masses have a convective core and a radiative envelope. The surface of our sun grainy because of convection cells right below ...
- 1,758
3
votes
0
answers
48
views
Strength of core-envelope coupling in stars (again)
I asked this on the physics SE but it received little attention:
Consider a high-mass zero-age main-sequence (ZAMS) (e.g., $m_{\rm ZAMS} \gtrsim 30\,$M$_{\odot}$) star.
I understand that the core-...
- 4,533
3
votes
1
answer
199
views
How can I estimate how long will a main sequence star stay on the main sequence given its temperature?
I have a generic zero-age main sequence star. The only thing I know about it is its temperature. How can I estimate time time it spends on the main sequence (in millions of years)? I've seen equations ...
2
votes
1
answer
189
views
Is it possible for a star to return in the main sequence?
Is it possible for a star to return to the main sequence after entered in the post-main sequence phase? I have no clue if there's a mechanism such as acquiring hydrogen from from the environment or ...
- 316
3
votes
1
answer
324
views
What would happen to the Sun's evolution if it collided with another yellow dwarf?
How would the Sun evolve if it collided with another G-type main sequence star, perhaps a more massive one like Alpha Cen A? Since its mass would then be above the Chandrasekhar limit, could it ...
- 293
9
votes
1
answer
1k
views
Increase in Luminosity of the star
The Luminosity of a star is proportional to the 4 th power of its temperature and square of its radius. Also the mass-luminosity relationship says that the luminosity of star is proportional to ...
- 157
4
votes
1
answer
117
views
Catalogs for type K stars and their planetary systems?
I am doing data collection on all type K stars, and their planetary system so I may develop an algorithm for a planetary formation simulation with the Unity game engine.
Where could such a catalog of ...
- 203
12
votes
1
answer
432
views
Is there a relation between mass, radius, and luminosity in deuterium-burning brown dwarfs?
I'm a worldbuilder and my setting has a lot of brown dwarfs.
While I'm trying to keep my setting as science-compliant as possible, I can't seem to find any resources for brown dwarfs like there are ...
- 163
2
votes
0
answers
90
views
The mass of Subdwarf B progenitors in the main sequence
Note: By "progenitor", I mean "the star as it was when it was still main sequence". Please correct me if I've got the terminology wrong.
Most B-type subdwarfs have mass roughly half that of the Sun. ...
- 495
8
votes
1
answer
551
views
Why does the convective core in an intermediate- to high-mass star shrink?
The image below shows the evolution of the hydrogen mass fraction profile for a 5 solar mass star in the main sequence. I would expect that the size of the convective core stays roughly constant as ...
- 199
3
votes
1
answer
1k
views
Is the turn-off point of the main sequence the same as the terminal-age main sequence?
The turn-off (TO) point is one tipping point on the Hertzsprung-Russell diagram (HRD) where low-mass stars start to evolve from the main sequence (MS) toward lower temperatures. If I understand it ...
- 199