Questions tagged [star-formation]

Questions related to the physical processes involved in or to the observations of the process of forming a star.

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What element drives pulsations in T Tauri Stars?

What element drives pulsations on T Tauri stars? I understand that T Tauri stars are variable and pulsate, and I also know that other stars pulsate as well. My thinking is that a T Tauri star would ...
13 votes
1 answer
1k views

Can stars form in the stellar halo?

The wiki page for Galactic Halo states: Star formation in the stellar halo of the Milky Way ceased long ago. In addition, the wiki page for Stellar Halo states: Astrophysical simulations of ...
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What direction do Herbig Haro outflows go from?

After doing some research about Herbig Haro objects, I found that the outflows are formed perpendicular to the circumstellar disk. Is that the same direction as the star's rotation, or is it the ...
16 votes
1 answer
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How are we observing the newly discovered "dark galaxy" J0613+52, if it has no stars and is so far away from other galaxies?

I just came across a New York Times article talking about a newly found Low Surface Brightness (LSB) galaxy (also called “ultra-diffuse galaxies” or “dark galaxies”). The new galaxy, J0613+52, was ...
5 votes
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Why do double neutron stars remain bounded?

I read that in principle, the formation of a double neutron star requires that at the time of the second supernova explosion the binary consists of a $\sim$ 1.4 solar mass neutron star, and a second ...
3 votes
1 answer
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Can a quasi-star develop a stable crust?

Could a quasi-star potentially develop a stable outer layer or crust during its early stage of formation if it were to be bombarded with substantial amounts of matter, coexisting with its core and the ...
1 vote
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How to decide and narrow down the broad topics I should get an astronomy internship on? [closed]

This is to inform that I am a third-year Physics Major student. I am enrolled in a five-year dual degree BS-MS programme at IISER Bhopal, India. I had a keen pop-science-like interest in astronomy ...
5 votes
2 answers
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The star that created our sun

Is the location of the star that would have created our sun known? Meaning our sun's parent star which would have provided the material when it died? If not, has there been any theories on what kind ...
7 votes
2 answers
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Is there a (proposed) name for Coatlicue's progenitor?

Our sun's theorized progenitor star carries the (proposed) name Coatlicue. Since our sun is thought to be a third generation* star there should be two generations preceding it - and therefore one ...
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How do the orbits of star systems V871 Centauri (septuple), Gamma Cassiopeiae (octuple), and QZ Carinae (nonuple) work?

Several years ago, I asked the question on here, "How do the orbits of Nu Scorpii and AR Cassiopeiae work?" At the time, these two stellar systems were the most populated (I don't know the ...
3 votes
4 answers
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How do stars 1 billion times the volume of our sun form and can they become black holes?

UY Scuti is a star 1 billion times the volume of our sun. A billion solar mass black hole formed 750 million years after the Big Bang. Could it have formed from a star like UY Scuti? Rare black hole ...
3 votes
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SExtractor parameters for identifying Star Forming regions

I am using SExtractor (Source Extractor) to identify Star-Forming regions in a galaxy. The problem is I am unable to choose the parameters required for it. SExtractor is just a tool to identify the ...
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Does most of the Sun's energy and light come from its black-body temperature, due to its massive size alone? Constant crashing of particles?

Stars have to be a certain size to initiate fusion to begin with, correct? Isn't this why brown dwarfs are considered 'failed stars'? But wouldn't the Sun (and other stars with sufficient mass, like ...
24 votes
3 answers
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Did the Sun's light always peak in the green wavelengths?

So, I know the sun is getting brighter over it's lifespan and I'm wondering how that affects its emission spectrum. The reason I'm asking this is because I find it weird that plants reflect green ...
9 votes
1 answer
852 views

What is the origin of the dust near the sun?

note: Solar Probe+ is now officially Parker Solar Probe In How can the Parker Solar Probe survive passing within 4 million miles of the sun's surface? I asked about the Solar Probe Plus mission. ...
10 votes
3 answers
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Can stars be born giants?

My understanding is that giant stars are formed when they leave the main sequence and begin to burn elements heavier than hydrogen. Can some stars, however, be born as giants or do all stars start off ...
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1 answer
201 views

How certain is the Sun's classification?

Curious Question here. How do we know the Sun is a G-Type Star? Our sun (Classed as G2V) apparently lies around the 5,780 Kelvin. Yet NASA generalizes it as 6,000 K- and is apparently white even ...
5 votes
3 answers
984 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 ...
7 votes
2 answers
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What kind of nebula was the Sun formed from?

I was just wondering what type of nebula did the Sun form from because mainly there are 5 categories: emission nebulae, reflection nebulae, dark nebulae, planetary nebulae, and supernova remnants, so ...
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How do I code the formula for the minimum mass of a stellar fragment from Whitworth & Stamatellos, 2006?

I was researching the formation of brown dwarfs, and I stumbled into the paper "The minimum mass for star formation, and the origin of binary brown dwarfs", and I am attempting to code a ...
4 votes
1 answer
639 views

Solar System formation, considering its and the universe's age

It is known that the Sun is 4.6 billion years old, and the complete Solar System is of a similar age. The class of stars to which the Sun belongs seems to be quite common. Stars of its class can live ...
5 votes
1 answer
116 views

Galactic orbits and distance between stars

In the context of whether or not nearby stars were created from the same nebula, this answer states: imagine two stars with very similar orbits, one with a period of 200 million years and the other ...
3 votes
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115 views

What is the average and the median mass and luminosity of a star?

I've heard in many places that the Sun is an average star, but in Wikipedia it says that about 75% of stars are M-type stars that are way less massive and fainter that the Sun. So how massive and ...
38 votes
2 answers
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Why are the Pillars of Creation pillar-shaped?

The Pillars of Creation have a strong directional sense. They are referred to as "pillars" and another question asks how "tall" they are. Naively, it looks as if there is a source ...
1 vote
2 answers
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Do stars made by universe getting smaller or larger in mass? [closed]

Do stars made by universe getting smaller or larger in mass compared to stars made 180 million years after the Big Bang? If they are getting smaller, is this due to the fact that the universe is ...
9 votes
1 answer
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Star formation - Is it just gas accumulation or does dust also play a role?

Inspired by the question, Are heavy elements equally distributed throughout the Solar System?, with a little further inspiration from this one as well, Star formation analogy, particularly the answer ...
5 votes
2 answers
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Could a quasi-neutron-star exist between the maximum mass of a star and the mass of a quasi-star?

A quasi-star is a hypothetical supermassive star that is so heavy its core collapses into a black hole as it is still forming. The matter accreting into the black hole then generates radiation ...
1 vote
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Has anybody measured the mass density profile $\Sigma = \Sigma (r)$ of a protoplanetary disk? (when $r<1$ AU)

I've been trying to find research articles where the mass density distribution $\mathrm{\Sigma = \Sigma(r)}$ is determined for protoplanetary disks, when $r<1$ au. For instance: Here A. Miotello, ...
-3 votes
2 answers
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Has the birth of a new star ever been observed (scientifically speaking)?

Not too long ago, Pluto was "demoted" because it no longer met the criteria for being a full-fledged planet. Similarly, in order to be classified as a star (and not, say, a proto-star, or ......
18 votes
1 answer
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How can a brown dwarf be more massive than a star?

SDSS J0104+1535 is about 90 times more massive than Jupiter, making it the heaviest known brown dwarf. EBLM J0555-57Ab has a mass of about 85.2±4 Jupiter masses, or 0.081 Solar masses. I am confused. ...
1 vote
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What happens if supernova undergoes in tightly close multi stars system

I do wonder in a tight or close orbital binary stars or multi stars system, if one stars undergoes supernova and that blast can lead another stars in the system to become supernova, too? Is there ...
4 votes
1 answer
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Difference between NSBH and BHNS mergers

What's the difference between Neutron Star-Black Hole Merger (NSBH) and Black Hole-Neutron Star Merger (BHNS)? Are they the same names for the same events or is there any difference between them? I ...
6 votes
1 answer
310 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 ...
3 votes
2 answers
586 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?
4 votes
3 answers
604 views

Why does the gas cloud collapse in regions of high density?

Stars form when gas cloud collapse under gravity, becoming hot and subsequently initiating nuclear fusion. I have read that the collapse is triggered by density fluctuations, where regions of high ...
2 votes
2 answers
721 views

What is the relation between Kelvin-Helmholtz timescale and free-fall timescale?

What is the actual difference between these two timescales? Both of these timescales define the time for collapse when there is only gravity. Also, what does it mean by saying Kelvin-Helmholtz ...
1 vote
1 answer
101 views

Massive star formation

Imagine we have a stellar cloud sufficiently massive to generate N high mass stars, what is the reason for this scenario not to happen? Because I know that when the jeans instability happens a star is ...
3 votes
1 answer
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The reason for an exoplanet density increase of planets closer to a star

From the NASA exoplanet archive system it can be seen that in the range of $0.02-0.06~\text{AU}$ distance an exoplanet is to its star, as distance drops down, the planet density increases linearly: A ...
1 vote
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what is the difference between Composite Stellar Population and Galaxy Spectral Energy Distribution?

I am reading Conroy et al. (2013), an extensive review on Stellar Population Synthesis technique, and I really can't get the difference between Composite Stellar Population and Spectral Energy ...
10 votes
3 answers
810 views

Why is the composition of the sun so distinct from that of earth?

Given that the sun is – in astronomical distances – quite close to the earth, why are the two composed of such distinctly different substances? Sun Composition Hydrogen 74.9% Helium 23.8% Oxygen ~1% ...
8 votes
2 answers
301 views

Can dark matter decrease the Jeans length?

I am wondering if there are any models of interstellar cloud collapse out there which take dark matter into account. If dark matter has local perturbations or density fluctuations, then that may be ...
2 votes
2 answers
169 views

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?
6 votes
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Are metallicities of molecular clouds lower in the outskirts of the galaxy?

(this question was originally posted in an answer by user PSR-1937-21 to another post. I find it an interesting one, but since they don't seem to be active anymore, I'm posting it to see if somebody ...
2 votes
0 answers
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Can distribution of stars / planets formation be a long-tailed one?

We know that peak of star formation already passed 10.1146/annurev-astro-032620-021910 and it looks like peak of planet formation occurred slightly after formation of Earth 10.1017/S1473550415000208 ...
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1 answer
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Why can't 'dead' galaxies start forming stars again if they merge with another, 'active' galaxy?

I heard Matthew O'Dowd mention on PBS Space-Time that dead galaxies cannot start re-forming stars even if they collect gas and/or dust from elsewhere, or even merge with another galaxy.... Why? And ...
1 vote
1 answer
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Has Altair flung off its planets by rotation?

This might be a dumb question, but would it be possible that during the star Altair's formation, the centrifugal forces became so large that its planets were flung away into space? Or could a passing ...
1 vote
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Is there a metallicity threshold past which star formation is impossible?

I've learned that metallicity is a very important factor to consider when talking about a star's formation and lifecycle. That gets me wondering whether a high enough metallicity could prevent the ...
6 votes
1 answer
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Activity of M dwarf stars

Why are M dwarf stars the most active (in terms of starspots and faculae) of all stars?
3 votes
1 answer
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Is the ratio $L_B / L_{H\alpha}$ important to determine star formation rates?

Could someone please tell me if the ratio $$\frac{L_B}{L_{H\alpha}}$$ is important in determining star formation rates? Additionally, could someone please explain the implication of the ratio to me or ...
11 votes
0 answers
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What is the birth of a star like? [closed]

Here's what I'm curious about. So this hydrogen gas collects and at some point, it eventually becomes a star. What does that process look like? If you were there as a witness to the formation of a ...