Stars Definition and 878 Threads

Homework Statement Centauri A and Centauri B are binary stars with a separation of 3.45x10^12m and a period of 2.52x10^9s Assuming the two stars are equally massive (which is approximately the case), determine their mass. Homework Equations ( m1 + m2 ) P^2 = ( d1 + d2 )^3 = R^3...

I happened to see this and thought someone here might be interested It has been accepted for publication in Astrophysical Journal and it suggests a reason for something I didnt know about---there are unexpectedly many young stars clustered around the vicinity of the SMBH at the center of our...

can someone Explain the NS-NS or NS-BH or BH-BH mergers proposed to explain short GRB’s. Thanks

http://sciencenow.sciencemag.org/cgi/content/full/2008/619/2 What do you think about the possible causes?

Hello, I have a question concerning general relativity. (go easy - I have only knowledge from general consumption physics books). Something curious I have been thinking about requires an explanation as to where I am incorrect in my thinking: My understanding is that, as something moves...

When a star or galaxy etc is said to be 10 light years away is that from a standard Earth's velocity distance (ie without length contraction) or do we take into account Earth's velocity and gravitation and have a standard length (maybe accordance with the milkyway being stationary or if we...

How come planets don't fall into stars as they orbit them? Einstein said a "space-time" curvature is caused because of the gigantic mass of the stars...why don't the planets orbiting these stars just fall right into them? Does it have something to do with the same reason why electrons never...

has anyone ever done research on the accretion of planets into a system without a star forming? Just a dark system. How likely is this to happen as opposed to a system forming with a star?

The Earth is effectively an insulator in space, and the sun continuously beats on the Earth with protons, electrons and other particles. Does the planet Earth and all other planets have a net charge, and if so, how can we measure the polarity and extent of that charge? Turning to the Sun...

stupid question, but why don't low mass stars experience nuclear burning beyond helium burning? I mean, after the helium's been exhausted, what's to stop the carbon core from contracting enough to trigger Si burning (or whatever element comes next).

Meet pair-instability supernova SN2006GY, the most extraordinary explosion in the cosmos. Unlike its smaller, regular supernova cousins, which blast off the outer layers of a star and pack what remains into a neutron core or a black hole, the pair-instability supernova is a much more violent...

[SOLVED] Extra-Solar Planets and their stars wobble Homework Statement An extra-solar planet is detected by observing that its parent star had a radial velocity 'wobble' of amplitude 40 m/s. If the parent star has a mass of one Solar Mass, and the period of the 'wobble' is four days, find a...

i was reading about an article about the keck observatory and its use of a laser to observe super massive black holes at the center of the galaxy. they talked about how they found young stars near the black holes and how it wasnt possible. so it gave me an idea. is it possible for black holes to...

I was out observing about an hour ago (finally found M51 for the first time :biggrin:) when I noticed what I assumed was a star to the northeast just a few degrees above the horizon. I looked at it and immediately noticed it appeared to be flashing, but not like an airplane. I stared at it more...

I have read some information, from various sources, pertaining to the orbital speed of stars about the center of galaxies, and some of it appears to be conflicting. Some sources claim that the stars closer to the galactic center orbit faster, while those father out, orbit slower. This of...

Can anyone help me get my head around this one? A star with a parallax angle of pi = 10 millisecs and has apparent magnitude of V= 10.2 How can I determine absolute magnitude: I have the formula M=v -5logd -5 +A which can be ignored. d=1/pi but I am always determining d which is less than...

Can two stars have the same apparent magnitudes but different absolute magnitudes? what about if two stars have the same absolute magnitudes but different apparent magnitudes?

Why are some stars larger than others? It is my understanding that hydrogen collapses due to gravity into a sphere and when a critical mass is achieved nuclear fusion occurs. Since the critical mass for this to happen is a constant shouldn't all stars be relatively the same size since a star...

Hello everyone - newbie here. Am I right to say that stars twinkle because of regions of the atmosphere being at different (and varying) temperatures and pressures etc., giving rise to a variation in refractive index and consequently a shifting image of the observed object? If so, why don't I...

Not sure where to put this post, care more about what's happening on atomic scaI le so i put it here. I am currently taking Heat transfer for engineers and we were discussing the mechanicals for heat transfer, conduction, convection, raditation. In class my professor said that conduction is...

hey guys, im doing a report on binary stars, using doppler shifts to get some results for periods etc but bit unsure about how to do the errors? i realize that the errors arise in the speed of the stars and the dispersion of the photons but how could i calculate this? cheers for any help x

A small but varied group of pictures we have for this contest. Please vote for the best picture of people dancing. 1. hypatia 2. ZapperZ 3. Ben Niehoff 4. matthyaouw 5. chroot http://virtualcivilization.org/alc5/images/IMG_0219.jpg...

How far away is the average star in the night sky? I mean, can we see stars that are on the other side of the galaxy? Perhaps most of the visible stars are maybe just a few dozen light years away?

[FONT="Comic Sans MS"]Dancing With The Stars This week, it will be pictures of people dancing! :) Zz. [SIZE="4"]Contest Rules: 1. Any digital photo or digitally-scanned photo relevant to the theme will be accepted within the contest period. In case there's a gray area, or you're not...

Is it possible to have a star drifting through intergalactic space?

Homework Statement "During most of its lifetime, a star maintains an equilibrium size in which the inward force of gravity on each atom is balanced by an outward pressure force due to the heat of the nuclear reactions in the core. But after all the hydrogen "fuel" is consumed by nuclear...

i found this, seems quite interesting; http://ieeexplore.ieee.org/Xplore/login.jsp?url=/iel5/27/4287017/04287093.pdf&arnumber=4287093 What do they mean by electrical stars? Is it that we should take into account the effects of the stars electrical field? or that a completely new model...

Help appreciated in advance... If one is in the NH, then a circumpolar star must have a declination greater than 90 - observer's latitude. But if one is in the SH, what is the corrected formula? do we just convert their latitude to -ve (e.g. 26 South becomes -26) and/or do we change the...

Hello: Sorry for my english. My suggestion is probably crazy, but... We can imagine what a advanced extraterrestrial civilization can create a star artificially, like we kindle a fire. Can you imagine some technique that posibilite this? Perhaps no all stars of universe are natural, perhaps...

Since each planet and star has it's own gravity which causes smaller bodies to orbit around them. Will our sun have an orbit around bodies with greater gravity than it?

Is this true or false? The state of our universe, as it is today, contains enough matter comprised of heavy elements, that the radiation from young stars will interact with this matter in such a way that it will be prevented from nearing the star, and thus the mass of the star, and all...

Homework Statement What is the combined apparent magnitude o a binary system consisting of two stars of apparent magnitudes 3.0 and 4.0 Homework Equations m-n=2.5 log(f(m)/f(n)) The Attempt at a Solution I know m= 3 and n=4 ,or vice versa. I'm not sure what this problem means by...

how does the movement of stars compare to the movement of planets

My question is about the formation of a neutron star once fussion stops and it collapses. I recently saw a show about the life of a star and it said when gravity overcomes the energy released by fussion, the electrons are compressed toward the nucleus of the atoms and create neutrons. I...

Hey! I have a question, whose answer I was unable to get after reading some articles regarding neutron start. I've understood that neutron stars lose their rotational energy and emit fragments of it to earth, thus slowing down through the years. I know that this process takes billions of...

hi there, i plan on becoming an astrophysicist/astronomer/cosmologist and recentley started looking for basic information into astronomy which i should know. i was wlndering if i am right about how stars are formed. i will try to put down how i understand: in the universe gas clouds could...

According to the second law of TD, entropy is increasing in the whole universe. Then how could you explain the fact that from a chaotic state of dust and gas remnants of a supernova, gravity causes all them to gather together to form new stars which are less chaotic thus having less entropy...

Okay look guys I am not posting this because I am a conspiracy theorist, in actuality I am trying to disprove someones insistence on a conspiracy theory regarding the lack of stars in photographs and video taken from space... I know there has to be some logical reason for this phenomenon, and it...

Hello, I really need help answering this question. I know when low mass stars die, they become white dwarfs (if their mass is less than 1.4M). But I don't know why the end points in the life of low mass stars help astromomers to understand the expansion history of the universe. How...

White dwarfs and neutron stars have very low uncertainty in position (since the particles are practically on top of each other), but a lot of uncertainty in momentum, and thus the claustrophobic particles vibrate with great momentum creating an outward force to oppose gravity, but doesn't a...

can you see the stars? hi, can anyone of you look and see the stars, for example, can you see the sun? kind of a puzzle:confused: lets see what do you think

Publications on the evolution of stars? Can anyone suggest a book that goes into detail on the evolution stars? I very much enjoyed as much as was discussed in Kip Thorne's Black Holes book and would like to read more about stars.

As I understand it we can use the principle of parallax to measure distances to objects within 400 light years from Earth. So how are the further stars and galaxies calculated?

I have a question about dead stars. I have only read about 2 ways a star can die. Either explode into a supernova or collapse into a black hole. It seems strange to me that when a star consumes all its energy that it could not simply become a huge lump of slag out there. Is it possible that...

Hi guys, I'm not to great at physics and all but I want to learn more. I hope you guys can help me in that aspect.First of all, how do neutron stars form? I was told their electrons shrink into their nucleuses and therefore the whole star shrinks, but what causes the atoms to behave like that?

If two white-dwarf stars combined together,there will be supernova?which type?--- (1)If two white-dwarf stars combined together,there will be supernova? which type? (2)If two neutron stars combined together ,there will be supernova? (3)If a white-dwarf and a neutron star combined...

This is an article in newscientist. http://space.newscientist.com/article/dn9428-massive-neutron-star-rules-out-exotic-matter.html Exotic states of matter such as free quarks do not arise inside neutron stars, according to a new analysis of one of the super-dense stellar corpses. The...

Do you think there are more stars in our Milky Way galaxy, or galaxies in the observable universe?

I know that in spectroscopic Binaries, you can observe wavelength shifts in each star. But how do you determine the total radial velocity of this system alltogether, and how do you find each star's radial velocity?

Isaac Asimov, in his 1979 book A Choice of Catastrosphes: The Disasters That Threaten Our World, raised the possibility that mini-black holes created with the Big Bang may burrow into stars and cause them to wink out (pp. 92-96). Stephen Hawking in 1974 suggested that (to quote Asimov) "...