Star Definition and 1000 Threads

The Equivalence Principle says depicting gravity as a field associated with matter is equivalent to picturing it as twisting of space. Is there a space-twisting equivalent of a collapsed star as a shell of condensed matter with interior of intense gravitational field energy (found in the field...

Hi! I'm not studying physics and what I know about light is mostly what I've read on the internet and what I've learn thinking and observing the nature. I come to realize that the space is full of light. When I look at the black space, I don't see light but I know that is light everywhere up...

How durable are the neutron stars, ie how long can they last? Will they "evaporate" like black holes or something else will happen with them after a very long period of time (eons)? Or are they immortal? I'm asking because I have found nothing clear about the lifespan of a neutron star.

This from Science daily, they these galaxies are producing a star every hour, is that possible? https://www.sciencedaily.com/releases/2016/03/160322161651.htm

Homework Statement (Assuming all circular orbits) [/B] Say there is a star with mass M and a planet orbiting that star with a mass m. The star M then suddenly loses half of its mass. (So now it is M/2) What is the new radius of orbit of the planet around the star? Warning: Velocity will not...

I am reading about mergers of a neutron star with a black hole and the association with GRB. While talking about the accretion disk, the paper I am reading says about the last stable circular orbit. Firstly I thought it was where the Roche limit lies, where mass transfer or matter ejection from...

Homework Statement P=Kρ^2 is a solution to the equation of the combination of the Hydrostatic Support equation and the mass continuity equation. Find the radius of the star. Homework Equations ρ(r) = (A / r) sin (root( 2πG/K) r) The Attempt at a Solution The first part of this was to prove...

If a comet is orbiting a star is there any work done? I understand that work is force * displacement, but the force must be in the direction of motion. In the case of a comet and star the star exerts a gravitational force on the comet, but this force is not in the direction of the motion of the...

Homework Statement We can make a rough estimate of how much the envelope of a red giant should expand as a result of the contraction of its core based on conservation of energy. We will consider a star of mass M and initial radius R, with a core of mass Mc and radius Rc. We will focus on the...

Hello, a long-awaited fan film has been released on Friday. I'd say it's pretty good.

Hi there, I have a question regarding the life cycle of a star. I know that when entering the red giant phase of a star's life, its radius/overall size will increase dramatically, but I was wondering if there's a basic way to determine the factor it will grow by during this process. I've seen...

Homework Statement *A star on the celestial equator has right ascension of 16h00m00s. At what time of day will this star be at it's highest point, on Febuary 29th 2016. * Homework Equations HA = LST - RA The Attempt at a Solution When LST=RA, it'll be at it's highest point. How do I...

Homework Statement (This is a long problem but I think the question is not hard.) Determining the star density from star counts is tough, but estimating counts from a density law is simpler. In practice, this method of fit-ting observed number counts to an assumed density law is becoming a...

Homework Statement I have this problem in an online assignment. Someone told me the answer, so I already got it right, but I don't know why my logic leads me to the wrong answer. The problem: The temperature u of a star of conductivity 1 is defined by u = \frac{1}{sqrt(x^2+y^2+z^2)}. If the...

Does this neutron star have an accretion disk?: https://en.wikipedia.org/wiki/IGR_J11014-6103#/media/File:Lighthouse_nebula.jpg

I was reading Stephen Hawking offers new resolution of black hole paradox. Most is over my head but when he mentions particles falling in through the EH, it raises a question. When a BH is created in a collapsing star, does the EH first appear at zero radius and grow outward, or does the EH...

Could neutron star jets with velocity greater than 0.9c be caused by a mix of ultra-relativistic core material escaping the star? See this link: http://www.dailygalaxy.com/my_weblog/2015/08/neutron-star-jets-near-speed-of-light-rival-those-of-black-holes.html

Hi , i would really like to have closure on a phenomenon i saw few years ago and still cannot explain. I myself is a science enthusiast and been studying. Ok, here it is : Created a rough animation of what i saw : View was much wider. Animation is made to reflect what i saw. Star is made...

I am trying to find the temperature of a star given its wavelength in micrometres, but I am not sure if my conversion is right therefore don't know if the answer is correct. Star A has a maximum emission wavelength of 1 μm and Radius 100 Rsun. What is its Effective Temperature and Luminosity...

Hello, I'm new to this forum and, to go right to the point, I created a fictional solar system for a tabletop RPG, appointing some characteristics that I want it to have, but I can't handle the physics to bring up the numbers - so I came here. To simplify it, this system only have 1 planet, and...

Is there any good information about the chemical composition of relativistic jets from neutron stars? If the chemical composition of the jets was different from the accretion material it could shed light on the process that forms the jets.

If a black hole had a mass similar to the Sun (I know black holes tend to be at least three times larger but let's assume an unusual series of events) how far would the are of extremely distorted bent gravity around it be could it cause closely orbiting bodies to be pulled or pushed out of orbit...

I have a friend of mine which is an extraterrestrial. She travels in a ship around the Milky Way. She was likely in the Solar System, and she wants to attend tomorrow New Year's Eve at Plaza del Sol in Madrid, Spain. Her last communication was that she had faced a violent cosmic ray storm, and...

OK so some stars evolve into neutron stars which I assume are so small (10's of kms) because ALL empty space is removed between the atoms.. absolute highest density possible? Now.. is a black hole larger (massive and in diameter) than a neutron star and called a black hole only because the...

When a large amount of plasma radiates greatly while accreting on a magnetized neutron star, where does the radiation ultimately get its energy from, the magnetic field and/or gravitational field? Without doing the numbers, if the magnetic field does the work against the gravitational field, and...

If a bubble of quark type matter formed near the core of a magnetized neutron star, what would happen to its shape? Would it elongate along the magnetic field lines? Could it burst out of the magnetic poles of the star?

Scheduled for release on July 22, 2016.

I've just wondered how it is possible for a planet so close to a white dwarf could exist. Yes, the atmosphere of the star during the Red Giant stage would have acted as counterbalance to mass loss, forcing it into a closer orbit. But it would have vaporized any normal planet or gas giant. Let...

How would one get the energy production in a star if only given the mass of the star? Something involving mc^2 I suppose?

Greetings! I read this article on line, where it states that Voyager 1 has an appointment with a star, AC +79 3888, which is 17.6 light years away, in 40,000 years. However, if voyager is traveling at 35,000 mph, that number seems off. Shouldn't it be 319,000 years to travel that distance? I'm...

Homework Statement A star cluster contains star HD1, which has an apparent V magnitude of 7.3 mag and a B − V colour of 0.5 mag. Its continuum emission peaks at a wavelength of 557.3 nm, and this star is known to have a bolometric correction of −0.4. (a): Calculate the distance to the star...

https://en.wikipedia.org/wiki/Mayall_II In the image, there is an odd Bluish-Green spec to the upper left of one of the lower bright background stars. I think it could be an LBV in the outskirts of the cluster. Any thoughts?

Haha :smile:

Hello all, I could be looking at this the wrong way but here it goes: From what I understand, if a star collapses into itself to form a neutron star, it would become more compact, denser and heavier with a larger gravitational attraction. Now, if I understand correctly, the size of...

by Ken Croswell Call it the case of the purloined star cluster. Observations reveal that our galaxy stole a distant globular star cluster from one of its neighbours. Link: New Scientist

New TV(?) series premiering Jan 2017. [ref]

Homework Statement a) The peak intensity of light from the Sun occurs at a wavelength of 500 nm. Astronomers discover a nearby star, “Nus”, which is the same size and mass as the Sun, but has a peak wavelength of half this value. Is Nus hotter or colder than the Sun and by how much? Nus is...

Homework Statement A star has an effective temperature T_{eff} and is observed to have a flux F. Show that the angular radius in arcseconds of the star (as seen from Earth) is given by \theta = (\frac{2.06 \times 10^5}{T_{eff}^2}) \sqrt{\frac{F}{\sigma}} Homework Equations L = 4 \pi R^2...

I saw somewhere a thread about a cow falling into a black hole. I don’t know why a cow, perhaps the OP was thinking about the Milky Way. With the cow example it is not clear to me what we are supposed to see when an object falls towards the event horizon. If time slows to infinity, does the...

In calculations of quantities in Neutron stars with degenerate matter is usual to set temperature zero. If I'm right it means that pressure of this matter is negligible against pressure due to Pauli principle. But what about situation when the matter is in neutron star locally compressed. How...

Homework Statement We have a Star with known temperature T, Radius R and distance from us. 1) Say we know the effective temperature ##T_{eff}## and we want to calculate the intensity ##I(λ.T) at λ=5500 A##. 2) Suppose that ##I(λ,T)## is constant over the range of visual band and...

Suppose a star passed by our solar system. How close would it have to come before the orbits of planets was significantly and permanently perturbed? How close to cast a planet out of orbit? Let's say that that star is a cold neutron star, so we know its mass (1.5 solar masses) and don't have...

Hi there, I´m reading about the theory of radiation and came up with some doubts when I started to calculate the net flux that an observer would "see" coming off from the star. I have provided my answers to my own questions but would like to see what you people think about them. 1. Can it be...

I read an article https://physics.le.ac.uk/journals/index.php/pst/article/view/716/516 that suggested graduate students (or higher) had actually bothered to 'calculate' the dilation effects on Luke Skywalker and Leia from Star Wars to show how they, whilst born as twins, could not be the same...

I can't think of an instance of this in science fiction, but then I do not have the broadest knowledge of the field, so I could have missed something obvious to everyone else. I wonder, though, could a planet form at the center of mass of a binary star system or be captured there, and could...

This is for a classed called Special Relativity and Math Methods. This problem doesn't involve special relativity though, since it's all from the same frame of reference. 1. Homework Statement Every 2 years, more or less, The New York Times publishes an article in which some astronomer claims...

I recently found a SF treatment I wrote years ago, based on the original Star Trek series and showed it to various friends as an idea for a new book. What was amazing was the near universal reaction as to how they all hated the wishy-washy New-Agey (common usage) new version with its strange...

imagine a hypothetical star composed of gluon stars, color neutral on whole, consisting solely of gravitationally bound glueballs. what would be its expected physics ? i.e for the mass of the sun, what would its radius be? would it emit radiation and if so what spectrum? would it be stable or...

Dear friends, Does anyone know how we can solve the TOV equations for a non constant density? In all the references, I just saw the solution for a constant density. Thanks in advance for the help :)

Dear PF Forum, I have question concerning neutron star and star just simply out of curiousity. 1. Can a star reach silicon burning stage then stop. It doesn't continue to iron burning stage. 2. Once a star reach iron burning stage, there's no stopping it to blast into supernova? Is supernova...