Star Definition and 1000 Threads

China develops new laser gun similar to Star Wars. It can burn through skin to produce immense agony. Here...

When neutron stars collide, heavy elements, such as gold, are created. Are these elements ejected from the system to be found, say, here on earth? Or do they fall back into the newly created black hole?

Hello everyone. I am trying to solve a problem whose statement reads as follows: Neutron stars have radii of ##\sim 10## km. If we assume that before the collapse the nucleus of the white dwarf precursor has a mass equal to that of Chandrasekhar, estimate the energy generated in the collapse...

A new planet has been visualized in a protoplanetary disk around a star. It's the bright thing at about 4 o'clock. Star (PDS 70) is blocked out. Science magazine news article here.

I'm trying to understand the Schechter function, I read on Wikipedia that the L star term in the function is the 'characteristic galaxy luminosity where the power-law form of the function cuts off'. What does this mean exactly?

How come the gravity of a stellar- mass black hole is strong enough to trap light but the gravity of a stellar-mass star (eg the sun) is not strong enough to trap light ?

Homework Statement A planet is in an elliptical orbit around a star. Which of the following best represents the mechanical energy E_planet of just the planet and the mechanical energy Es_tar-planet of the star-planet system as functions of time for one complete orbit? Homework Equations...

Homework Statement [/B]Homework EquationsThe Attempt at a Solution I tried T=E/L = 30 X (1.989X10^30) X 0.1 X (3 X 10^8)^2 /(8X10^5 * 3.828X10^26) =1.75 x 10^15 s = 1.33 x 10^9 years . However the answer is 4x10^5 years please help

A star or a planet is a material object, while a black hole is an 'immaterial' spacetime object. Does the material or 'immaterial' nature of an object make any difference in how it curves or travels through spacetime as it manifests gravitation (apart from the powerful gravitation near a black...

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...

How fast would you have to go to reach a star 240 light years away in an 85-year human lifetime? Here, I know that I'm supposed to find $v$, but I'm having a hard time setting up my equation(s) in order to reach the final answer. :(

Hi all, I've been tasked with computing binary star orbits based on their initial parameters, positions and velocities. In this problem everything must be expressed in terms of the masses, but I am struggling to define positions and velocities in terms of mass. It is assumed that the stars are...

If this is true where is the core of that star, either a neutron star or a black hole should exist near by, right?

In a PDF presentation on star formation that I'm currently reading, I ran into the following statement: "If we observe an increase in a star's temperature but without any changes in its luminosity, it means the star is shrinking (its radius is decreasing)" I'm having trouble understanding...

Will teleportation, like in Star Trek or many sci-fi movies, where people disappear with a puff of smoke, ever be possible in the real world. Will we ever be able to build something that can do this, and what would it be like?

Homework Statement attached: I am stuck on question 2, and give my working to question 1 - the ##B(r) ## part I am fine with the ##A(r)## part which clearly is the same in both regions seen by looking at ##G_{rr}## , and attempt, however I assume I have gone wrong in 1 please see below for...

https://phys.org/news/2018-03-evidence-star-disturbed-prehistory-solar.html https://academic.oup.com/mnrasl/article-abstract/476/1/L1/4840245?redirectedFrom=fulltext (abstract) R. de la Fuentes, S. J Aarseth Based on an earlier paper (E. Mamajek 2015) that indicated Sholz's star passed very...

There was a lot of discussion after the recent observation of the merger of two neutron stars about whether or not these events are the source of the heavier elements. See this thread, for example. This recent paper has some new analysis. Especially interesting is Figure 10, that I've...

(In this one I personally do not believe. But surprised I could be, who knows...) Trailer 1:

Homework Statement I have to calculate the mass of an astrometric binaries with P=10 years, and a1=15mas, parallax w=64mas the luminosity is neglected Homework EquationsThe Attempt at a Solution i used this equation: M_1 + M_2 = \frac{(a/w)^3}{p^2} but the problem is taht i don't have M1

I find a very interesting site that shows us what it would be like to travel to a black hole or a neutron star. https://apod.nasa.gov/htmltest/rjn_bht.html Have fun !

I know, in our solar system, the asteroid belt is very rare, and the rings of Saturn is thin. But can dense asteroid clouds exist elsewhere? For example in a binary star system, where constant changing of gravity prevent the forming of a planet from chunks?

Any clues of the plots in Star Wars Episode IX (after the Last Jedi)? I hope they would introduce more fearsome adversaries.. so far .. the most fearsome character was Darth Maul.. But he was not that scary.. he even looked a bit boring... Star Wars must introduce characters that can send...

Homework Statement Question: Vega is a star of spectral type A0V at a distance of 7.76pc and has by definition ##m V =m B =0.0\space mag.## Observations of a star cluster show, that all stars in the cluster with a spectral type A0V have an apparent magnitude of ##m V =15 \space mag## and a...

We just discovered the maximum mass of a neutron star, discovered after the recent neutron star merger event back in Aug. They say that the maximum mass of a neutron star is approximately 2.16 solar masses. So I always assumed that the lowest mass for one is 1.4 solar masses, the Chandresekhar...

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...

https://www.sciencedaily.com/releases/2018/01/180116093650.htm This article gives a maximum weight of 2.16 solar masses, and an infinitesimal addition would turn it into a Black hole. I can not find a paper to support this article so do you think it is correct?

https://arxiv.org/pdf/1708.01789.pdf In line whit LQG which renders time(Tomita time) to evaluated differently. Would it be possible for a bounce scenario in Blackhole. This is the update from the old paper of Planck Star http://arxiv.org/abs/1401.6562 . -- It is something to with how time...

Hello. First post here so hi all. My question(s) is regarding the formation of solar masses by accretion of gases and dust. From what I understand, stars are formed by large clouds of gasses and dust particles pulling together and with enough gravity, (magnetic fields), and time. A fusion...

I'm reading about star spectra, color, and temperature and have a question... I understand that very hot stars burn blue because a lot of the radiation is on the UV end so it appears more blue when its ran through several color filters. and the opposite applies for cool stars that are skewed...

Homework Statement Homework EquationsThe Attempt at a Solution When the source is not moving, ## \lambda = 6250 A ## ...(1) When the source is moving, ## \lambda ' = 6500 A ## ...(2) From (1) and (2), ## \lambda ' > \lambda ## ...(3) This means that the source is moving away from...

Homework Statement Homework EquationsThe Attempt at a Solution I think : the question means that almost all of the potential energy gets used into the explosion. If this is true then the potential energy gets reduced by ## \frac { GM^2} R ## or if the star just gets transformed into a...

Homework Statement The Cepheid variable star l Carinae pulsates with a period of about 36 days. During each pulsation, the star becomes about twice as bright and its radius grows by about 25%. (a) In its smaller state, the star has a surface temperature of about 5100 K. Treating the star as a...

I've seen many people who is studying it.. but why ? is there any contributions to physics at a foundamentalist level ? I mean, the properties of matter inside nêutron stars is the interesting part to theoretical physics and not the whole object right ?

Can the Sirius star system support physical life in any way including those that can breath carbon dioxide or other gases?

Note: this is QM question, not about stellar science. I am not asking what are the lightest neutron stars found in the Universe. The same star (say, 1 sun mass) can exist both in a form of a white dwarf and a neutron star. Both states are stable. However, let's say I start to stripe outermost...

https://www2.jpl.nasa.gov/teachers/attachments/parallax.html It's written that they find the distance by calculating from the parallax angle. But how do astronomers find the parallax angle?

I have heard that whatever we know about stars experimentally is through only what we can see from its surface since the light from the interior is "hidden." However, when we look at the spectrum of a star, we do see absorption lines for heavy elements. I think the reason why that is is because...

Hello, I recently watched a video as an introduction to Feynman diagrams for my own self-interest. The video gave a link to practice problems, and one of them was as follows: In a neutron star gravitational collapse causes valence electrons to combine with protons. Draw a Feynman diagram...

Hello, can I ask you if you have some experience with hyperion modular eyepiece adapter? I would like to know what is its main advantages compare to standard eyepiece ( as it is about ten times more expensive..) thank ou...

Homework Statement It is my idea so I hope there is no problem in assignment. How long takes small black hole to eat an ordinary star, if the black hole sit in the center of star? Homework Equations We probably should suppose that star is ideal fluid (incompressible). (1) ##\frac{dm}{dt}=A\rho...

So, I have this scenario: A neutron star with radius R = 13 km Time for 1 rotation is 3,150807 ms, so frequency f about 317,379008 Herz Mass 1,97 times the Sun's which is then 1,97*(1,9884*10^30) kg Extra given information: the magnetic axis is aligned with its rotational axis (not that likely...

iPTF14hls was a supernova discovered in 2014. Typically they reach a brightness peak quickly and then fade over few months - but this star had several oscillations in brightness. To make it more confusing, archives from 1954 show a supernova at the same spot. News article This model can lead...

Homework Statement I need to first find phase current in the load and line current from the supply Homework EquationsThe Attempt at a Solution I thought it would be easier to work with a star because then the Ztl would be in series with it... I am not sure how to find the current but my best...

Homework Statement I am studying for an exam and I never know if I am finding line current / voltage or phase current / voltage. How can I tell? I guess I am confused on what "phase" and "line" represent. For example: If I do the voltage divided by the impedance, then this gives me phase...

Hello, When we talk about the luminosity, apparent magnitude or absolute magnitude of a star, are we talking about all wavelengths of EM radiation or just a certain range? I've read that luminosity is basically the power output of all types of radiation, but the apparent magnitude scale is...

Is there a theoretical limit to the size of neutron stars? It seems likely neutron stars are not simply electrons orbiting a proton so what is their life cycle? Can they just evaporate slowly by neutron decay?

Bear with me, I am just a chemist. Observations took several days (up to two weeks if memory serves me well). What I wonder is - why had different types of the EM radiation came at different times? Gamma burst was observed at almost exactly the same time gravitational waves were detected, but...

I have seen it claimed online that the recently announced observation of a neutron-star merger by LIGO provides strong support for the hypothesis that heavy elements - gold and platinum were mentioned in particular - are mostly created in neutron-star collisions rather than in supernovas. Is...

I don't mean a black hole, I mean an actual functioning star that is black to our (human) senses. What that would mean is that a star that is so hot, that it produces hardly any radiation in the visible part of the spectrum, nothing lower than ultraviolet. I mean it's possible from the other...