Questions regarding large spheres of plasma undergoing fusion.

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3
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1answer
33 views

In 31.5kyr, Epsilon Eridani and Luyten 726-8 will be < 1ly close; but how distant from the Solar system?

Greetings! Based on Wikipedia and more precisely this paper, it is said that, in about 31,500 years, the stars Epsilon Eridani and Luyten 726-8AB will "meet" at a very close distance (less than 1 ...
2
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2answers
111 views

Solar Pressure and Gravity

I recently read some articles and pages on Solar Sails, and the possibility of using lasers to propel spacecraft, and I had a relatively outlandish idea. Would it be possible for a star to be ...
0
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0answers
38 views

Stars repartitions

I'm looking for the stars repartitions in percent, in the Harvard Classification (from O to M) I have search every where but I found nothing. I'm not looking for exact values, but more generic ...
3
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1answer
139 views

Do stars tend to fuse all hydrogen even when the mass is small?

Suppose a brown dwarf requires only one more hydrogen atom to become massive enough to start fusion, what will happen if we add a hydrogen atom to it? It fuses until the mass is dropped and then ...
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0answers
40 views

Is our sun part of a triple star system with sirius binary? [duplicate]

What if our sun is not a solitary star exception? Pluto turns around the Sun, but from Pluto the Sun is very small. Idem, the Sun could turn around a very big and very far star looking very small ...
0
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1answer
43 views

Metalicity and age of bulge stars vs halo [duplicate]

From what I understand of current models, the bulge of the galaxy formed first, and thus, would contain older population II like stars. Currently, however, the halo has a higher population of stars ...
0
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2answers
122 views

Are we made of stars we're seeing? [duplicate]

a fresh astronomy enthusiast here. Recently I've been reading upon how immensely far other stars are from our solar system and how is it possible that we may be seeing stars that are already dead. My ...
4
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2answers
57 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 ...
1
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2answers
65 views

How to interpret extreme ultraviolet/ x-ray data in the literature?

I am interested in a sun-like star 138 light years away that is in the EUVE catalog. A table shows that a photon count of 2.6+/-0.5 photons per kilosecond at 100 angstroms has been detected for this ...
4
votes
1answer
125 views

Are larger stars rounder?

The Earth is a very smooth sphere, and the Sun even more so, with only minor fluctuations. I am wondering: are larger stars even rounder? Intuitively, that seems self evident, but I am not so sure. ...
3
votes
3answers
150 views

What Makes Stars Hot?

Simple question, but can't seem to find the answer anywhere. It can't be nuclear fusion because nuclear fusion occurs as a result of the heat. And it can't be because of gravity because it's believed ...
2
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2answers
42 views

Triple stars with retrograde orbits

Where can I find the observed frequency of triple star systems where the outer star is in a retrograde orbit?
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1answer
58 views

Mass of Star Collapse

Does a star, when collapsing into a neutron star, or even a black hole, pick up any significant relativistic mass due to its rapid collapse rate?
3
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1answer
121 views

Why is the Sun's brightness and radius increasing, but not its temperature?

On the Sun's article on Wikipedia, there is an image showing how the Sun's brightness, radius and temperature have changed over time: For the past (and next) few billion years, I see the luminosity ...
7
votes
3answers
536 views

What decides the direction in which the accretion disk spins?

Planets lie on the same plane because of the accretion disk formed during the Protostar stage, as I read in this question. I also read about the collision of particles in the gas cloud causing the ...
5
votes
3answers
145 views

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 ...
0
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1answer
84 views

Can you see the stars when it is trickling?

I am writing a book with the following scene in one chapter: It is trickling and my protagonists are outside looking into the night sky, looking to the stars. Reviewing the scene I am wondering: Is ...
4
votes
1answer
108 views

What happens if two or three stars collide with each other?

After finding out that there is a solar system with three stars, I did extensive research. I couldn't get a definitive answer. What would happen if they collided with each other? I know there would ...
26
votes
3answers
6k views

Did I see another planet?

A couple days ago, I zoomed in with my 30x optical zoom camera, and after some exposure adjustments, a bright star in the night sky turned into this: Are those other planets or other stars? Or is ...
2
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1answer
45 views

If a star were to suddenly lose nearly all of its stored heat, would it be able to return to its normal state? [closed]

If not, would it be possible to approximate the maximum heat energy a star could lose before the change became irreversible?
0
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1answer
89 views

Sun like star in our milkyway?

Is there any popular star or one which we can see with our naked eyes in our milky way that is atleast 90% sun-like(mass,radius,spectra,luminosity).The important thing is it must not be a binary. Its ...
0
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1answer
96 views

Cluster of fast moving stars

We live in NW Tasmania in a country town and tonight out walking I pointed out a long cluster of stars to my sister as they made an unusual shape but then we realised they were moving really fast - we ...
0
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1answer
70 views

How to determine the mass of a runaway star?

I would like to know how do astronomers estimate the mass of a star that has been ejected from its galaxy. What kind of accuracy can be achieved?
1
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1answer
83 views

Create a signal to noise map from heatmap

Recently, I obtained my heatmap from a sky survey. But now, I'm trying to get a signal to noise map from my heatmap. My heatmap looks like : My colour bar indicates the number of stars per pixel ...
1
vote
2answers
54 views

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, ...
0
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0answers
52 views

After the Sun becomes a red giant, will most of the nucleosynthesis still be from proton-proton fusion?

After the Sun becomes a red giant, will it continue to mainly run on the pp-fusion, or some other type of reaction, like the CNO cycle or the triple-alpha process? On that note, do most other stars ...
0
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2answers
122 views

Why are black holes that massive?

Today known most massive star, R136a1 weighs approximately 256 times the mass of our sun, how did supermassive black holes, with a mass of 10 billion times the sun form? I understand, that when a ...
2
votes
1answer
67 views

Given a collection of pixels, how to deduce the flux from them?

I've obtained the coordinates of brightest pixels from different images (.fits files) using Python. I want to get the flux of each pixel. How do I go about finding out the flux?
0
votes
1answer
29 views

How to calculate B-V colour index value percentage difference

I need to calculate a percentage difference of a B-V colour index between its estimated and actual value. So I tried doing this by difference between values/actual value x 100. However as B-V values ...
12
votes
1answer
1k views

Do star remnants actually burn?

As we know, some stars can fuse heavy elements to produce carbon and oxygen after using up hydrogen if they are massive, and the remnant of stars are usually hot, my question is, if a star fuse to ...
4
votes
2answers
100 views

Rate of Mass Loss from the Solar Wind

This is problem 1-4 from Principles of Stellar Evolution and Nucleosynthesis by Clayton: Assuming at the Earth a characteristic velocity of 400km/s and density of 10amu/cm$^{3}$ for the solar wind, ...
0
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1answer
47 views

Stellar data for data mining [closed]

Where could I find detailed data from stars? Like spectrum, x ray and so on ? Because I would like to do some data analysis on it.
5
votes
2answers
287 views

Does natural satellite(s) of a planet affects its orbital velocity around a star?

Please excuse me for a lay question. As we know, to calculate the orbital velocity, we take the mass of the orbiting body, the mass of the body being orbited and the distance between the two bodies ...
5
votes
2answers
151 views

Why when we look through a telescope in space, do the billions of stars not block our view from seeing further?

I know that we are able to "see back into time" by looking very far away through telescopes such as the Hubble telescope, but my question is, wouldn't you run into at least a couple of stars that were ...
0
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1answer
93 views

When stars explode why can we still see them?

This might be a silly question but if light travels at the speed of light and time is frozen in that speed then why the stars we see could be dead already and not just instantly disappearing from the ...
3
votes
1answer
347 views

Where do new stars get their hydrogen from? [duplicate]

When stars run out of hydrogen, they explode (though they also use heavier elements for some time) and form nebulae. In the nebulae, new stars are born which use hydrogen as their fuel. So, my ...
6
votes
1answer
459 views

How do star densities work?

If we take a look at stars more massive than the Sun, their densities vary a lot. UY Scuti is an extremely low-density star that's only 8.5x more massive than the Sun, but is 1000-2000x its size. ...
4
votes
1answer
72 views

Why do pre-main sequence stars show lithium in absorption?

This paper and this paper state without discussion that the presence of lithium absorption in the stars they observe as strong evidence of these stars being pre-main sequence stars. Because they state ...
1
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1answer
25 views

How to see other celestial things using stars for direction?

I have a simple question. I can see orion constellation clearly in the night sky. I read it somewhere on this website that gemini is on the left-hand side of orion constellation. I was able to spot ...
-1
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1answer
46 views

Can a drastic change in a stars cycle cause harm or affect a nearby star system?

If Alpha Centauri A our neighboring star happens to shift into a Red Giant or a Planetary Nebula, Will our star system be affected? And if so is there a ripple effect throughout the galaxy causing a ...
4
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2answers
133 views

Why are stars more metallic closer as you move closer to the galactic bulge?

As I see it, most of the stars in the galactic bulge are Population I stars. However, as one moves farther from the galactic bulge, star metallicity decreases. In fact, halo stars are almost entirely ...
2
votes
1answer
184 views

Are stars really “burning balls of gas”?

Even the NASA website refers to stars as "big ball of gas". It's a common statement that's popularized by movies and popular culture. However, stars are technically not in a gaseous state - they're in ...
3
votes
1answer
203 views

Are there good animations of the movement of proximate stars over long time periods?

After reading about Barnard's Star and how it's approaching us 140 km/sec, I'm curious if there are any visualizations of how the nearest stars to Sol will be moving over the next 100k years or so. ...
4
votes
3answers
293 views

Could the KIC 8462852 (Alien megastructure star) be explained by orbiting gas clouds?

I was wondering about the light dimming of the 'alien megastructure' star. From what I understand, for it to be a planetary body, it would have to be some 20 times the size of Jupiter. Is it possible ...
1
vote
1answer
51 views

Epsilon Eridani and Sadira

I have seen a number of places on the Internet where Epsilon Eridani is referred to as Sadira. (e.g. https://en.wikipedia.org/wiki/List_of_stars_in_Eridanus ) However, it would seem that its an ...
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2answers
128 views

Number of stars & planets in Milky Way Galaxy?

Is there any specific numbers on stars & planets count on Milky Way Galaxy ?
1
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1answer
92 views

how to get image coordinates of source points in saoimage ds9?

I loaded my fits image to saoimage ds9. Then, Analysis->Catalogs automatically brought up source locations. how can i get xy image coordinates of this source locations?
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0answers
73 views

Formulas for gravitatitional equilibrium

I am trying to calculate at which point gravitational equilibrium sets in for various bodys (planets stars neutron stars etc.) assuming they are perfect spheres. However the radius i get is not equal ...
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1answer
61 views

Obtaining stars vector position in relation to the center of the galaxy at a given date

How can someone obtain such vector, for stars in the Milky Way? Input should be star data (from a catalog, eg: Hipparcos) and Julian Date. Output should be a Vector Position (in pc) in relation to ...
0
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2answers
42 views

Do massive OB stars accrete mass the same way as the black holes they turn into do?

It is often said, in spite of sci fi often having illustrated the opposite, that stellar mass black holes do not gravitationally attract material in their environment into themselves anymore than a ...