Star Definition and 1000 Threads

Homework Statement Homework EquationsThe Attempt at a Solution the solution says to equate the moments about C or equate the centripetal forces but the moments, they used M1R1 = M2R2 how does the above represent the moment, and why is the moment even equal?similarly, why is the centripetal...

That, anyway, is the headline in today's news, regarding the interesting discovery announced by NASA overnight of the planet dubbed Kepler-452b. As I understand it, the properties of the planet are inferred from spectral analysis of its effects on the light from the star which it orbits...

FWIW

Is it possible to calculate how much Helium a star can produce when it reaches the end of the main-sequence, right before it starts burning Helium ( given if it has enough mass to do so) ? And if it is possible then is it also possible to calculate how many materials a star can produce given...

Homework Statement The intensity of the Sun's radiation is about 1380 Wm-2 at Earth's distance, 1.5x1011m. Earth absorbs this radiation as a black body, and radiates its own energy back into space. a) How much Energy per second falls on the Earth's surface? (Diameter of Earth = 12800km) b)...

Hi guys, I am trying since a while to put in equation the evolution of a star's central density, temperature as it leaves the main sequence but has not reached yet the burning of Helium. So there is no nuclear reaction in the centre and the core is slowly collapsing. Does anyone have some...

I was thinking about this the other day, and I was curious about what future stars will contain for their cores. If I understand correctly, the first generation stars in the early universe didn't contain (or contained significantly less) metals. As stars evolved, they contained more metals (or...

Dear PF Forum, I'm just wondering about P+P reaction in star. Because of its pressure, in the core of the star, hydrogens fuse to become deuterium. Its the complete reaction P + P -> D D + P -> He3 He3 + He3 -> He3 + P + P and if the star is big enough, it can undergo CNO cycle, But what if...

I was doing some research on the findings of the Kepler space telescope this morning. I noticed that some of the stars it has found are quite small, and some of the planets in other systems are quite large. Is it theoretically possible for there to be a situation somewhere in the universe where...

Dear PF Forum, I've been searching the answer for this particular question about neutron star in google, but I don't find it, yet. 1. What is the temperature of a neutron star, right after it is formed from supernova? 2. Can anybody give me some timeline about neutron star cooling down? 3. What...

First, may I apologize in advance if this question is in the wrong section of the forums. Given a cloud of mixed gasses and rocky material, how is spin created when a star is born? I will also give the cloud of gas a random order of movement prior to star formation. Can the physics for the...

Homework Statement Planet 1 orbits Star 1 and Planet 2 orbits Star 2 in circular orbits of the same radius. However, the orbital period of Planet 1 is longer than the orbital period of Planet 2. What could explain this? A) Star 1 has less mass than Star2. B) Star 1 has more mass than Star 2 C)...

Dear PF forum. Folks, what I have here may be an unimportant question. Still I'm curious to know the answer. When iron fusion happens in a massive star, it will undergo supernova. What I want to know is... 1. There are some binary (or perhaps ternary) neutron star systems. Neturon star is...

I think about a space opera, and a Death Star like scenario in it. I intend to make it harder than SW. I had the following idea : they hollowed out a big metallic asteroid, spinned it up, kept a large portion of the outer layer as armor, and built a fusion reactor in the middle of it. They want...

I'm guessing folks have seen this... but if not. Pretty awesome. I have the annual Astronomy Magazine Calendar, and it never get's old. But this is a step up. Probably a better site for the vid...

If you take the spectra of a star you usually have a big primary mirror (lets say 1m) to get a lot of light, and use an exposure time usually several tens of minutes. Can one use an astronomical spectrograph for a led/arclamp light source? How does the light intensity of a star compares to...

As I am new to this forum, I must apologise if I have began this thread in the wrong category but I have a bit of a problem. I don't necessary study physics, I study Electrical Installation at college. As a result we overlap on some physics topics We have recently covered Star Delta. Now, I...

If we have an equation that looks like $$H=Y$$ and we want to multiply H by either $$ReM_{IJ}$$ or $$ImM_{IJ}$$ where $$M_{IJ}$$ is a complex matrix. But the thing is that $$Y=\star(...)$$ where $$\star$$ is hodge star and (...) is set of complex functions and other numerical stuff, my question...

My physics book mentions that a stars luminosity is its total power output at all wavelengths and that absolute magnitude is defined as inherent brightness and NOT luminosity. It then mentions that two stars of the same power output have the same absolute magnitude. Since luminosity is the...

I try to find answer to quite basic question. Let's imagine neutron star and object with mass of 1 kg located far from the neutron star. Total energy of the object is ##E = U_g + mc^2##, for case when its velocity is zero and and ##U_g## is potential energy of gravitation. The neutron star have...

From what I understand, in the equation P=\sigma AT^4, P is the power output of the star which is the energy radiated per second in EM radiation of all frequencies, and I think luminosity is also defined as the energy radiated per second in EM radiation of all frequencies. Therefore luminosity...

I recently read this kind of question on Quora and found it interesting. Do all of the Earth's materials(and therefore humans) belong the same star of different star? What's more likely? In my opinion, the chances of all of the material belonging to one star are pretty slim because a complex...

According to the concept: when a planet revolves around a star, and when both the bodies move in circular orbits due to the interaction between each other, both the bodies can be replaced by a single body of mass ##\mu## revolving in a circular orbit of radius equal to the distance between both...

These two types of stars clearly must have different properties because they form distinct groups on a Hertzsprung-Russell diagram. I have also read that red supergiants can form elements up to around carbon by nuclear fusion, whereas red supergiants can form up to iron, however there doesn't...

Homework Statement Consider the path of a comet orbiting a star, the system of the comet plus the star. Which of the following statements are correct? Select all that are True. 1) As the comet slows down, the kinetic energy of the system decreases. 2) As the comet's kinetic energy increases...

News Story US 708: Hypervelocity Star Ejected by Supernova Breaks Galactic Speed Record I recently posted about a link about a hypervelocity globular cluster. Today a story comes out discussing the fastest known hypervelocity star. SDSS J093320.86+441705.4 It is a white dwarf star apparently...

What does the metric matrix look like for a binary star system? Does each follow its usual geodesic about the other? It seems like the solution would have to be different somehow than that for a tiny planet circling a big sun.

I read an article (Planet 'Reared' by Four Parent Stars) the other day and came across the statement: "Astronomers think it's highly unlikely that this planet, or any moons that might circle it, could sustain life." I began to wonder why, but there was no further explanation in the article...

In researching a planned post about M87's globular clusters, I again have been diverted. Being a rank amateur, I was studying how to use Aladin. Looking at some YouTube videos, I found this odd one, "Planet Like Object Found on ALADIN". The object looks bizarre, like the guy drew it in the...

I read that nebulae are formed by stars exploding and they are also thought to be the birth place of stars. Stars explode when all the hydrogen atoms are fused into heavier elements and they are no longer able to fuse heavier atoms right ? If that's the case then the nebulae should contain...

Neutron stars are supposed to have an upper limit in mass, beyond which they collapse into perhaps a further type of degenerate matter or a singularity. There doesn't seem to be precisely defined upper limit, but the limit is estimated to be 1.5-3 solar masses. However, a hypothetical neutron...

Eric E. Mamajek, Scott A. Barenfeld, Valentin D. Ivanov, Alexei Y. Kniazev, Petri Väisänen, Yuri Beletsky, Henri M. J. Boffin. THE CLOSEST KNOWN FLYBY OF A STAR TO THE SOLAR SYSTEM. The Astrophysical Journal, 2015; 800 (1): L17 DOI: 10.1088/2041-8205/800/1/L17 The Science Daily article...

The fastest moving pulsars are theoretically spinning neutron stars. They probably got their velocity from a kick from a supernova like Project Orion. http://chandra.harvard.edu/photo/2012/igrj11014/ http://chandra.harvard.edu/photo/2003/b1957/closer_look.html As I understand it, neutron stars...

Hello,Im searching something that called Jeans anomally i don't know how is this spelled in english i find it hard sometimes to translate terms. It's about the birth of a star as far as i know but i can't find nothing on the internet :)

Hi everyone, Is there a simple formula/equation for calculating the mass of a star simply by measuring it's redshift. I know there is a way to do it, but have been unable to find any clues on the web.. Thanks for your help! :)

I was thinking about the motion of two stars in a binary star system, but there is something I cannot quite figure out. Suppose you have a binary star system with two stars masses m1 and m2 with m2>m1 so that m2 is closer to the centre of mass of the system. Then when the two stars are as far...

Good night! Please, what happens to an object (eg a spaceship) placed exactly in the center of mass of a binary star system (composed by two similar stars)? Would it be compressed by a huge gravitational mass (something like the mass of both stars)? Would it be stretched and torn? Or would it...

Homework Statement For the balanced three-phase loads shown in FIGURE 3, ZY = (15 + j15) Ω and ZΔ = (45 + j45) Ω. Determine: Uploaded file C1.png (a) the equivalent single Δ-connected load, (b) the equivalent single Y-connected load obtained from the Δ-Y transformation of (a) above, (c) the...

Can someone explain why the probability of the inclination angle of a binary system being less than i_0 is 1-cos(i_0) i.e. why the fractional distribution of binary stars is df = sini * di, where i is the inclination angle? Where does the sin i come from? Why is not not uniformly distributed...

I am rather a beginner to this field .So please forgive me if this is a very meaningless question. QUESTION: If I were to somehow increase Jupiter's mass by adding more hydrogen to its atmosphere, can i ever reach the stage where the mass of the planet becomes enough to undergo gravitational...

Homework Statement Homework EquationsThe Attempt at a Solution a) the question is to transform star to delta ?

I had a question and I found a thread on PF with a nearly identical question ---Slowly add mass to a neutron star till it collapses. I learned some very interesting physics from that thread, namely the Tolman–Oppenheimer–Volkoff limit, and the significance of "9/8 of its Schwarzschild radius"...

sir, 1)star connection 3ph motor(415V) which load location is suitable? 2)delta connection 3ph motor(415V) which load location is suitable? 3)star&delta connection 3ph motor(415V) which load location is suitable? please support me.

Hey! :o I want to write a function for the constitution of a star system "ss". The new star system contains an empty list of planetary system, that means that in the list of the planetary system exists only the sentinel node, and the empty tree of the free-floating planets (ffp). The new star...

This Facebook video is said to be of the star Rigel, taken with an Ipad. Comments?

Ok, silly question. Lexx is a sci-fi TV show that ran from 1997-2002. In one episode they used 'approximately 14.2 Quadrillion Quadrillion drones" to basically suck matter away from the star slowly using gravity. Ive always wondered: Do you think this is possible? Or would such a large mass...

Released, the teaser trailer has been

Can a extremely massive star ( eg. thousands solar masses) be formed?

Homework Statement Exercise 2.6 (page 28) Consider completely ionized matter consisting of hydrogen, helium, and heavier atomic species i>2. Let X and Y denote the fractions by mass of hydrogen and helium, respectively. Show that \mu_e=\frac{2}{1+X}. Approximate m_i=A_i m_u for all i, and...

Just curious if uranium could gather in enough quantities so that it's gravity will keep it from blowing apart or will critical mass start a chain reaction and prevent this configuration into a "fissioning" star