Stars Definition and 890 Threads

https://www.sciencealert.com/matehmatical-model-of-cold-dark-matter-bose-einstein-condensate-stars Interesting read. Thoughts and comments?

What is the shape of very massive stars? Are they simply spheres or something else?

I've just watched a vid about jets of matter and neutron stars. It was stated in it that a neutron star is a star that's been compressed from say a sun sized star to the size of a city, every thing OK upto now. Then it goes on to say that it has, the neutron star, enormous gravity, this is were...

From, https://www.syfy.com/syfywire/wham-bullseye-galactic-collision-creates-a-ring-of-black-holes-and-neutron-stars ..."“So you have a nice, normal spiral galaxy, right, just out there doing its thing, when BAM! A smaller galaxy careens right through the middle of it like a bullet! Chaos...

Hello everyone. I'm currently working on NS mass relations and trying to plot a curve with predicted masses-radii and observations on NS. There are some free data at this website: http://xtreme.as.arizona.edu/NeutronStars/index.php/neutron-star-radii/ . I downloaded the .tar file and tried to...

Black bodies are objects that don't reflect radiation. But If I shoot light beams to the sun, it doesn't reflect it , so does that mean the sun is a black body(or at least very close to a theoretical one)?

Blackbody radiation spectra of hot light sources ( stars in this case) should have the full visible light spectrum and still stars less massive than the Sun emit reddish light while stars more massive than the Sun emit blue light. How is the blackbody radiation spectrum altered by the star mass?

Homework Statement The two components of a double star are observed to move in circles of radii ##r_1## and ##r_2##. What is the ratio of their masses? (Hint: Write down their accelerations in terms of the angular velocity of rotation ##\omega##) Homework Equations ##m\ddot{\vec{x}}=...

When a high mass star starts to fuse heavier elements, the core heats up the outer layers enough to for them to begin fusion of their own. My question is: because the star hasn't gained any mass, but it has increased in temperature a lot, why doesn't the star expand and cool like a red giant...

We know that solar corona is heated up although we don't know yet the mechanism. I was wondering which other type of stars, else than G2, in the main sequence suffer of the same effect? Thank you!

There are red giants, blue giants. white dwarfs, red dwarfs, brown dwarfs, etc., etc., etc,... Why? do they have different chemistries? Are they each at different stages in their lives? Is there a combination of reasons?

I am having a issue with part a) of this question, I am not entirely sure if what I am saying is correct, could somone if possible check my logic 1. Homework Statement Two solar type stars (all physical properties are the same as for the Sun) are in a close binary system. Each individual star...

Some new papers appeared about processes in the collision of the two neutron stars, measured in August 2017. Is now more clear, why 2 second delay between gamma rays and gravitational waves happens?

When a cloud of gas reaches a critical density, thermonuclear reaction occurs and a star is born. all other gas is blown away by the staller wind. So how do we get stars so much more massive then the sun?

Astronomers can determine the presence various elements in a star through spectroscopy of the incoming light from that star. The characteristic spectral lines of each element are formed by electrons transitioning between the various orbital energy levels around the nucleus of their atom. But...

So for some reason, from time to time, i always come back to this question and i can't remember that part of the physics while i was studying and most of the explanation are pretty generic. Basically how do we know that light actually travels and not just oscillate and transfer energy when...

In solar system, we have sun and planets revolving around it. We have satellites orbiting around some of planets. Are all of these are same thing, just differentiated on the basis of size and nuclear processes occurring inside them? I mean, if nuclear processes occurring inside their core its a...

I just an read article on the ESAs Gaia program. I was wondering how they count the 1.7 billion stars in the image? Are the stars cataloged as the images are taken? Or is there a method that is used after the images have been collected? http://sci.esa.int/gaia/60169-gaia-s-sky-in-colour/

Hello.Long time,No See. I am just wondering if anyone can point be in the correct direction. Preferably with a link or a book that I should read as i would like to understand, not just know the answer. I am just wondering how much the number of stars in the universe has changed over time...

Hi! I'm trying to understand a perfectly black body. So the definition I have found is that a black body is one that absorbs radiation of ALL wavelengths and reflects NONE. Therefore it appears black at low temperatures. And when heated it emits radiation of all wavelengths making it appear...

I'm trying to understand why convection is an efficient mode of energy transport in the outer layers of the solar interior. Could anyone give me a little bit of knowledge? Thank you!

Can anyone enlighten me as to why the total thermal energy of a star will increase with time if the star has no nuclear energy source?

I have read somewhere that the parallax method can be used to measure the distance to stars up to 400 light years away. I did a quick calculation and estimated that it means that our telescopes can resolve an angular movement of 8.15x10-3 arc seconds. Taking the distance between the sun and the...

Hi everyone. I'm looking for a good book or some good source of informations about the stantard solar models, but i can only find compact stars stuff. Do you guys have any sugestions ?

A Japanese company wants to use a satellite to make shooting stars in 2020 for the Olympics in Japan. Later for the world.

Hi, I would like to raise a question about Role of magnetic field while formation of small to medium scale stars emerging from nebula ?

Homework Statement ##\alpha##-Centuary is in a binary visual system with another star. Their separation, from their CM, is 8.0'' and 9.7''. The distance from the Earth is 1.31pc. Their revolution period around the CM is 80.1 years. I have to find masses and luminosities for each star. Homework...

Im wondering what the night sky would look like if you stood on the surface of the Earth as it was forming? Here is my best guess, I would like to know if I am on the right track 1. After it cooled down, it had no atmosphere so it would be like the surface of the moon so the stars wouldn't...

https://www.space.com/39837-first-stars-universe-fingerprints-dark-matter.html...

I have a question regarding the results of my Physics investigation on Tc and Teff of stars. I found that the colour temperature that I calculated is significantly higher than the Teff for O and B stars. For mid temp stars, Tc is still more than Teff but the difference in small. But for cooler...

Homework Statement [/B] The top spectrum shows part of the Sun's spectrum. State and explain which letter best represents the light from a star that is similar to the Sun. Homework Equations None. The Attempt at a Solution I originally was thinking A but my book says B but only gives...

Hello everyone! I am a moderator over at the VS Battles Wiki, and I have some questions I believe one of y'all can answer. Basically the question is: how much energy does it take to destroy a star? We find this with GBE, but I have some questions as to calculating this value. As far as I am...

From Wikipedia: Quark-degenerate matter may occur in the cores of neutron stars, depending on the equations of state of neutron-degenerate matter. It may also occur in hypothetical quark stars, formed by the collapse of objects above the Tolman–Oppenheimer–Volkoff mass limit for...

Has anyone else heard of that gravity waves may be the result of another type of supernova remains, called a Grav-Star? It seems almost to physically mimic a neuron star but stopped just shy of becoming a black hole, yet it still has enough of a gravity well to prevent light from escaping. Is...

Ive been reading about it for a while and I'm still confused. i understand that a star is not a perfect blackbody. but do stars absorb radiation from space and then re-emit that energy into space?

The sources I've looked at claim the magnetic field is present because there are still some electrons in the neutron star. Here is how I understand their reasoning: a star's radius significantly decreases when it collapses into a neutron star, ultimately decreasing its moment of inertia. In...

I read in some books that as the sun approaches the end of the fusion process(the complete one) , it will expand and engulf some of the inner planets. But why will it expand?

How does one determine/calculate the masses, orbital period, and separation of two merging neutron stars from the characteristics of its gravity wave LIGO signal? And how does this information allow one to calculate the distance to the galaxy that housed the merger? And how can one calculate...

Can a supernova produce some number of stars after it explodes or will it always produce just one, single star? Can the matter it ejects form multiple stars and solar systems or will there always be just one new star and its only new solar system?

My question might seem simple, however I couldn't find data on this. Let me explain my situation: I'm involved in a project about the formulation of new criteria to avaliate exoplanetary systems for search of extraterrestrial intelligence. The key question is mostly around the element...

I hear wild varying estimates of how many stars there are in the Milky Way Galaxy, from 200 billion to 400 billion. Is the number closer to 200 billion or closer to 400 billion? What methods are being employed (other than GAIA) in order to count them?

I have a sci-fi idea regarding being able to move planets around like billiard balls. I'm theorizing that, after a nova, some of the bands of material around a star formed a new ring of rocky planets around a Neutron Star. Naturally, these are bathed in radiation. Having never taken high...

Hi there, I love physics and I'd like to begin a bit of astronomy. I want to invest in a beginners telescope but I haven't a clue about what to buy. Some that I'm looking at are linked here: https://www.amazon.com/dp/B00XQMLA7Q/?tag=pfamazon01-20...

How frequently is collision of stars in galaxies? If there are 100 bi galaxies and 100 bi stars each, then how many collisions should we expect in within, say, 1 year?

Boson stars seem to be a good fit for Dark Matter. https://arxiv.org/pdf/1704.05057v1.pdf Can you help me understand why such a huge particle with such low mass can exist, and how it could be found experimentally.

I read an article today stating that the possible explanation for the near total absence of heavier elements such as gold and uranium in many galaxies may be due to those galaxies not forming around a central black hole that has in absorbing one or more neutron stars causing fusion of neutrons...

Has the spectrum of a ball lightning ever been photographed? If so, does the spectrum look like the spectrum of any star? Could one say: the ball lightning is the smallest existing star?

Rumors are starting to fly that LIGO/VIRGO sees a signal of merging neutron stars, with an optical counterpart. Indeed, the thing that seems to have triggered the rumors was having a number of telescopes suddenly pointing at the same patch of sky. It's difficult to discuss the science behind...

Before today, I'd been led to believe that collections of only one (or few) types of matter could never exist: And to my surprise it is indeed possible to have degenerate matter, resulting from the death of less massive stars! So I'm curious: If these lesser massive stars collapse due to their...

Homework Statement Hi, I am studying for a test on Monday and I was wondering if someone could clarify something in my notes on the ionisation rate of Type O stars. The line in my notes says; L = 105L0 ⇒ S* ~ 105 /13.6eV ⇒ S* ~ 1049 Basically, I don't have an actual formula for S* and I was...