All Questions
Tagged with star main-sequence
26
questions
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 ...
- 825
7
votes
3
answers
1k
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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, ...
- 156k
3
votes
1
answer
200
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 ...
- 156k
4
votes
4
answers
4k
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Why is the main sequence often called 'zero age' main sequence?
The main sequence stage for a star begins after it stars burning hydrogen into helium. This is often referred to as the zero age main sequence.
This is confusing since stars have already lived ...
- 156k
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 ...
- 59
2
votes
1
answer
320
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?
- 156k
4
votes
2
answers
659
views
Why do post main sequence stars enter the red giants branch?
I am an early graduate student in astronomy and have hard time understanding why do post-MS stars move up the RGB.
Here is what I understand about post main sequence evolution of stars. As their ...
- 2,668
3
votes
2
answers
600
views
How can pre-main sequence stars radiate more energy than main-sequence stars?
How can a pre-main sequence star radiate more energy by gravitational contraction than a main-sequence star can by hydrogen fusion?
- 156k
11
votes
1
answer
550
views
How does a star's rotation affect a star on the main sequence?
I searched and have found that the questions mainly focus on neutron stars, white dwarfs and black holes. This was not what I want.
Basically, the bigger the star's mass is, the more intense its ...
- 310
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 ...
CommunityBot
- 1
8
votes
1
answer
552
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
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
200
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 ...
- 126k
2
votes
1
answer
191
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 ...
- 6,684
3
votes
1
answer
325
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 ...
- 6,684