Questions tagged [star-formation]
Questions related to the physical processes involved in or to the observations of the process of forming a star.
97
questions
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1answer
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What exactly are infrared dark clouds and what is the significance of the orientation of their magnetic fields?
In the video Why NASA's SOFIA Telescope On A Plane is "Perfectly Balanced" after about 10:04 SOFIA associate director James Jackson says:
We have a spectrometer ...
6
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0answers
55 views
How much of a molecular cloud can end up as “starstuff”?
Stars form within molecular clouds. These clouds can be up to 6 millions solar masses. When the cloud collapses into stars, is it possible to know a rough figure for how much of this material actually ...
2
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0answers
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Freefall timescale for a Jeans-unstable hydrogen cloud of mass M
I'm working on a project (personal, not academic) that involves calculating the collapse timescales for protostars which will end up becoming stars of varying given masses. I'm treating the pre-main ...
5
votes
1answer
93 views
Will the conditions that allow life to evolve still be around in a trillion years?
Some billions of years ago, systems like the Earth couldn't emerge and therefore life couldn't arise, because not enough of the heavy elements had formed yet.
Assuming there'll neither be a big ...
0
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1answer
76 views
Estimating a star's radius, temperature, and luminosity based on its mass
(See updated figure and description below.)
I've been trying to generate ballpark estimates for the radius, temperature and luminosity of stars in the main sequence based solely on their masses (...
14
votes
2answers
363 views
Characteristics of the first planets in the Universe?
What would have the very first planets looked like, based on their most likely chemical compositions?
For example:
Were they mostly grey gas giants with atmospheres of hydrogen and helium, ...
1
vote
0answers
33 views
How many parent stars contributed to our solar system? [duplicate]
All of the stuff that isn't hydrogen and helium (which came from the Big Bang), that coalesced to form our solar system (the iron, the sulfur, the water, and so forth) all came from previous ...
2
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0answers
59 views
Formation of the First Stars
I've got a few questions about the first stars to form in the universe. First off how might metalicity have impacted the formation of the first stars and also what effect would the absence of metals ...
4
votes
1answer
37 views
How to model and subtract nebular emission lines from stellar spectrum
I have optical stellar spectra from a star forming region with spatially varying nebular background.
I want to subtract the nebular lines from the stellar spectra (which are varying in intensity from ...
12
votes
2answers
198 views
What will future populations of stars be like?
As stars slowly using up hydrogen and ejecting heavier elements into space, the future stars will form from nebulae that are more metal and helium rich.
The question is: how does the increased ratio ...
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vote
0answers
85 views
What is the physical reason of the mirror principle in the stellar evolution?
I understand that stars transition into the red giant phase by obeying the mirror principle, as written here:
Shell-burning stars obey something called the mirror principle, which is an observation ...
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0answers
92 views
Stars readjusting themselves in the sky [duplicate]
I had a meeting in the evening and thought of grabbing a snack before that. I stepped out of the office along with a colleague. He was on his phone and I was simply staring at the sky wishing it would ...
4
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0answers
46 views
Do stars come on like LEDs or wick lamps? [duplicate]
Is stellar ignition an instantaneous thing - before, dark, after, shining brightly - or more of a process over time? In fusion research 'ignition' appears to be an event, but maybe in a protostar it ...
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0answers
58 views
What is the most mass that matter likely to form?
If we plot graph between accumulate of forming mass (y-axis) and mass (x-axis), where is the maximum ?
There is a story how I get this question. It start when I think about question "Is our sun is ...
0
votes
1answer
103 views
What is the lyman-werner background?
I've seen several papers that discuss the Lyman-Werner Background (LWB) when modeling star and galaxy formation in the early universe. One in particular (https://arxiv.org/abs/1803.04527) even varies ...
0
votes
1answer
55 views
How could a supernova seed solar nebula?
If the heavier elements such as Uranium came from a supernova, then this supernova had to sit somewhere right in the middle of the original solar nebula, because although the ejected matter traveled ...
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vote
2answers
155 views
Why does star formation cease?
The universe is expected to have a time when star formation slowly ceases. However, this seems bizarre as there is always an abundant amount of matter in the Universe. Massive amounts of hydrogen ...
3
votes
1answer
56 views
Stellar nurseries in the “Shedding New Light on the Whirlpool Galaxy” video
Captions in the Hubble Space Telescope YouTube channel video Shedding New Light on the Whirlpool Galaxy say:
(visible) Along the dark dust lanes, bright pink nebulae are the birthplace of new stars....
16
votes
2answers
4k views
Could stars form outside of galaxies?
Is it possible for there to be a dense enough nebula to form stars outside of any galaxy? Does a galaxy have a minimum size to produce stars? Or could you have a few dozen stars clustered together by ...
5
votes
1answer
59 views
Activity of M dwarf stars
Why are M dwarf stars the most active (in terms of starspots and faculae) of all stars?
3
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2answers
135 views
A few questions regarding the transit of planets
Here we will be concerning ourselves with the transit of a planet with it's parent sun.
I have a few questions that I am not sure about:
1) Do all planets transit their parent sun? It would seem to ...
1
vote
2answers
210 views
Remains of the progenitor of the Sun
It has been argued that it is not possible to trace back the remains of the progenitor star of the Sun (sometimes called Coatlicue), which, being estimated in the mass range of 30 $M_{\odot}$, should ...
1
vote
3answers
241 views
Can a donut-shape planet or star be formed?
How stable is that configuration and under what conditions such object may form ?
Is there any evidence suggesting that such objects might exist ?
0
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3answers
172 views
Is there any definitive proof of stars being “born” in nebula formations?
Is there any absolute evidence of star formation inside of nebulae (AKA stellar nurseries) as is suggested and even stated as fact by many textbooks?
5
votes
2answers
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The formation of new stars as depicted in Feynman's lectures
I've stumbled upon this curious passage addressing the formation of stars in Feynman's lectures on physics:
Whether we have ever seen a star form or not is still debatable.
Figure 7–12 shows the ...
5
votes
2answers
222 views
What does the ']' in the spectral line “CIII] 1909 Å” mean?
The above emission line, as I understand, is a useful probe of early star-forming galaxies.
However, I do not understand what the ']' to the right of the 'CIII' means.
I could not find any online ...
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votes
1answer
150 views
Black-hole becoming a star again - follow-up question [closed]
Some questions have been posed about black holes becoming stars again once they attract enough hydrogen/atomic matter from another star. Some answers were a forceful NO. Never. However - let's ponder ...
2
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0answers
49 views
What's the profound reason(s) why the star formation rate drives the scatter of the mass-metallicity relation in galaxies?
Since decades it's well known that a correlation between stellar mass and metallicity (Z; both stellar and gas-phase Z, but here I focus on the gas-phase Z) exists (e.g., Tremonti+04; analysis of >...
5
votes
1answer
299 views
Black Dwarf Capabilities
Can a black dwarf be suitable for manned exploration, once it cools down? And potentially used for space mining?
10
votes
2answers
137 views
Star formation around rotating black holes?
Please excuse an amateur question.
While trying to think of anything but what was happening during a dental procedure my mind turned to a model of a star close to a rotating black hole and the ...
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vote
0answers
39 views
Doubt about star formation [duplicate]
When a star runs out of hydrogen, it either goes through supernova or forms white dwarf and planetary nebula. So there should not be much hydrogen left to form a new star in the nebula. So how new ...
31
votes
1answer
5k views
If two white dwarfs collided, would they become a star?
Would the temperatures during such a collision be able to ignite nuclear fusion, bringing the dead star back to life? If so, would it only be able to fuse for a short time before running out of fuel, ...
2
votes
2answers
151 views
Will all of the gas in the universe be converted into red dwarf stars?
Red dwarfs have lifespans of trillions of years and are also the most abundant stars, making up 70% of the stars in the Milky Way. No red dwarf star has ever died and none will die for a very, very ...
12
votes
2answers
1k views
How did the lighter elements end up in the center of the solar system? Solar System Formation
The previous generation of stars famously are the origin of all the heavier elements (up until iron?) in the solar system. So a big portion of the solar system mass actually is made up of Carbon, ...
4
votes
2answers
177 views
If two binary brown dwarfs began to exchange gas with each other, would they both ignite into stars?
If two brown dwarfs got close enough to exchange gas with each other, could it trigger nuclear fusion within their cores? Is it possible for two brown dwarfs to orbit so closely and become a ...
2
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3answers
188 views
Term for the moment when hydrogen fusion begins in a star
I have read of this process many times, but I don't think I know the term specifically for the moment when hydrogen fusion begins. What is this moment called?
2
votes
1answer
229 views
How was the Sun formed?
Refer to the below minutephysics video, in which they say that in order to reach the Sun from earth, we must first stop revolving around the Sun ie make our tangential velocity zero, and then head ...
3
votes
1answer
162 views
What are infall signatures in stars?
I came across several papers (e.g. Looking for outflow and infall signatures in high mass star forming regions P. D. Klaassen, L. Testi and H. Beuther, 2011) talking about infall signatures in star ...
3
votes
3answers
371 views
How do we calculate heat flow or cooling rate for no fusion brown dwarf star?
I was reading this article and it said something that didn't sit right with me.
"SIMP0136 still gives off light mostly in the infrared wavelengths, as its temperature is now approximately 830° C (1,...
0
votes
1answer
80 views
Spacing of G and K class stars
I was looking at the Wikipedia article "List of potentially habitable exoplanets" and I noticed that many of the closest planets listed(tens or hundreds instead of thousands of light-years away) ...
3
votes
1answer
145 views
What are IRAS sources?
Do IRAS sources refer to star forming regions? I searched google and I came to know that it stands for IR astronomical satellite.But what do they search for? Please help me
5
votes
1answer
111 views
How long will star formation endure before the eventual heat death of the observable universe?
Lord Kelvin's prediction of heat death indicates the eventual end to star formation in the observable universe. Have any astrophysicists made any predictions for the endurance of star formation in the ...
12
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2answers
2k views
How are binary star systems created?
I don't know how common it is for a system to have two stars (or perhaps even more) but how do they arise? Is that due to the stellar accretion disc, or the composition of the stellar nebula?
Or are ...
6
votes
2answers
695 views
How were the first stars formed?
In class, we read a Scientific American article, "Cloudy with a Chance of Stars" that explained how the cores and the dust around them formed stars(he called them eggs for a chicken/egg analogy, where ...
3
votes
1answer
124 views
Sky in the very far future / past
Motivated by this question about a stranded submarine in the Jurassic I would like to know:
Is there anything remotely left of our current skyline if we go back or forward millions of years so that ...
2
votes
0answers
326 views
What characteristics or patterns do galaxies have on color-luminosity chart? [closed]
For the following graph, I have some confusions:
How do galaxies rank by mass? We know that on main-sequence, more luminous stars are also more massive, so I guess it also applies to galaxies.
Do red ...
0
votes
1answer
745 views
How do we know a star's age based on its spectrum? [duplicate]
A star's nearby environment may give clue to its age.
Different stellar type have different spectral features. If we just have its spectrum, how do we know its age?
For example, a star may be born ...
0
votes
1answer
124 views
I have some questions about star formation [closed]
Q2 What does the phrase 'containing several distinct knots of collopsing material' mean?
Q3 In this context, does the word 'such clouds' mean protostar? (I'm not an English-native speaker.)
Q4 In ...
4
votes
2answers
381 views
Sun's formation as “part of a star-forming-cluster…”?
After reading this interesting answer,
I was wondering, do we in fact know if our Sun in particular was created as part of a star-forming-cluster, or, was it more of a solo creation?
(Or, are all ...
5
votes
1answer
258 views
What is the origin of the dust near the sun?
In this question I asked about the Solar Probe Plus mission. Reading a 2008 report I saw that there is an elevated exposure to high velocity dust near the sun. I understand the high velocity, anything ...
