Stars Definition and 878 Threads

I want to check circumpolar stars for the observer whose latitude is 26 degree 28 minute 12 second North (My office). From here, latitude = 26 degree 28 minute 12 second North, all stars with a declination higher than +63 degree 31 minute 48 second are such circumpolar stars. And stars with a...

Apparently VY Canis Majoris is 30–40 solar masses, also there's R136a1 which is 265 solar masses. How do they remain stars with all that mass?

It is my understanding that when an electron drops to a lower orbital that 2 photons of light are produced. The moving electric charge produces EM radiation just like moving charges in a radio transmitters antenna produce EM radiation. Energy in the form of radiation, heat, or whatever else, can...

Hi, I've been looking at the Hertzsprung-Russel diagram and was wondering exactly what types of stars collapse to form a black hole? What temperature range/radius etc. turn into black holes. I understand that its most likely the supergiants that form black holes, but what about the giants? Are...

How many stars does one create and how many times can stars be recycled into more stars?

Hi everybody When you have observed the complete revolution of a star around an other one, you can derive the mass of the double star system (the sum of the masses) by using the Kepler's third law. That's OK. I have heard that you can find the mass ratio of the system by using...

The Earth's rotational velocity at the Equator is 1,674.4 km/h or 465.1 m/s. The stars at the equator rotate at that same rate taking in account Precession at that particular time of the year and the longitude & latitude they are viewed from. Do the stars at the poles rotate faster then at the...

I was wondering, does anyone know of a lower limit on the mass of a neutron star from fundamental physics? That is, the smallest it could be before its pressure would make it explode. I don't mean the Chandrasekhar limit, as that's the upper limit for a white dwarf. Neutron stars occurring...

These places seem great. Do places like these actually appear this way with the naked eye?

Homework Statement I'm working with the polygons on the interior of stars that have been drawn in a specific manner. For an example, I'm currently using a 16-gram. To construct the same one I have, you array sixteen vertices equidistant from one another around a central point (as in the...

Recently I visited a sea water aquarium with tropical fish anemona, corals. At the glas walls I observed little (about 1 cm diameter) white stars with 6 legs. Now starfish have 5 legs, as far as I know. Any idea what this could have been?

Hi all, I've read somewhere that at least 20% of our galaxy's stars have planets orbiting them? But what is the share if we include all kinds of rocky bodies? How likely is it that stars suck in everything without leaving any leftover material what so ever? I'm curious because the Drake...

Homework Statement Deep in space, two neutron stars are separated (center-to-center) by a distance of 18 X 106 km apart. Neutron star A has a mass of 153 X 1028 kg and radius 52000 m while the neutron star B has a mass of 159 X 1028 kg and radius 72000 m. They are initially at rest with...

Hipparcus indicates that our supposed closest star alpha centuari is 742 marcs parallax, which corresponds to about 1.3 pc or 4.3 yrs away. Since stars form in multiple; hence our sun has sister stars at much closer distance, with higher parallax values. Also infrared telescope could be used to...

Why are some stars so much more massive than others? Eta Carinae and The Pistol Star are 100X more massive than the Sun. When stars are forming, doesn't hydrogen fusion begin at about the same mass and density for all stars? Or does chemical composition and rotational velocity of the nebular gas...

We break down the received light stectrum from a star into the individual wavelength components. From it we claim to know its composition, heat, distance and speed. Aren't there way more unknowns that knowns? For example, consider any arbitrary observed star with a certain color distribution...

Hi, Do stars flicker colour and intensity in the night sky? I was in an argument with a friend of mine, and he told me stars can flicker 300nm in wavelength at 15Hz. I told him that I thought his eyes were just confusing change in intensity with colour. Was I wrong? Thanks:smile:

Don't know if anyone seen it, it's out today in a journal: http://www.msnbc.msn.com/id/42787604/ns/technology_and_science-space/ Sounds interesting, one of the first to catch my attention for a while (perhaps I just like big numbers...).

Hello everydody. Well i need to write a repor (5 pages maximum) about Core Collapse of Massive Stars to my discipline Stellar Structure and Evolution . The problem is that i have read some books like https://www.amazon.com/dp/0387580131/?tag=pfamazon01-20 and i have no ideias. I gained...

http://nerdapproved.com/misc-gadgets/dolphin-laser-pointer-keychain/" So in the above image they have little attachments for laser pointers that can make different designs. I've played around with similar types of attachments for laser pointers and have never thought about the physics...

Dark matter really due to stars having some charge?? I have an acquaintance who has a physics doctorate who argued the (to me) novel idea that dark matter doesn't really exist; that a plausible explanation of the observations suggesting it is that stars are sufficiently not exactly electrically...

Do all stars have to be present inside of a galaxy? Or are there some stars that can be out side in intergalactic space? I was just curious. Thanks

Hello all! I have to calculate the required mass to ignite the PP chain when the given temperature is 4*10^6K and \mu=0.62. (I know the answer is about 8% from the sun's mass)… I don't know exactly how to do it :-/ I know that (R/Rsun)=(M/Msun)^(3/7), The energy per nucleon in PP process is...

Why do stars "twinkle?" I can't think of a better word for it Why are there 4 "spikes" coming out of the star? What optical phenomenon causes this? Why do some stars twinkle and others not? Thanks

Earlier today I took a break from following the thread here on the Fukushima Nuc Plant problems (very interesting, by the way) and watched some TV, specifically a show I recorded on the formation of Stars. It reminded me of something that has been bothering me for some time - Gravity and how it...

Homework Statement A binary star system consists of two equal mass stars that revolve in circular orbits about their center of mass. The period of the motion, T = 25.5 days, and the orbital speed v = 220 km/s of the stars can be measured from telescopic observations. What is the mass of...

Homework Statement we are looking at two stars in the eridani system, eri B and eri C. the period of the system is 247.9 years. the system's measured trigonometric parallax is 0.201 arcseconds and the tru angular extent to the semimajor axis of the reduced mass is 6.89". the ratio of...

Homework Statement The question asks for the fraction of all 2M(sun) stars ever made in the Galaxy that are still burning on the main sequence. It assumes star formation at constant rate. The age of the Galaxy is 10GYRS To do this I imagine you use the salpeter IMF and find the constant...

Will black dwarfs eventually quantum tunnel into neutron stars if proton decay doesn't occur?

I'm wondering about the visual appearance of neutron stars up close. Do they continue to emit light like a white dwarf? Can cooled ones be gray or black? The xray emissions from pulsars will not be visible to us. Due to their high mass, they will bend light in a similar manner to a black hole...

There is a great deal of misconception and misinformation surrounding the topic of radiation pressure in stars. I have found there to be a widespread idea that the cores of stars are held up primarily by radiation pressure, yet this is very rarely true. To see how bad the misinformation there...

I have 3 questions: 1)Does the lines in the spectrum of a star indicate the elements in its surface or also the inner parts? 2)when an electron goes to a higher state, it emits a photon with a wavelenght according to that transition, and we can see that line in the spectrum of that star? But...

I thought others might be interested in this: http://arxiv.org/abs/1011.6142 As a nuclear physicist, I don't find it surprising to hear that neutron stars are superfluid. Nuclei are superfluid. I'm not clear on the relationship between superfluidity and cooling. Can anyone explain this using...

in analysis of close binary stars, it is assumed that their orbits is circular and then by a rotating coordinate system, potential is obtained and then lagrangian points and so on... Is the orbit of CLOSE binary stars nearly circular in reality or is it assumed circular because otherwise it is...

This is the exact question: Stars in a globular cluster are observed to be one magnitude redder (in terms of B-V color, so the color excess E_(B-V) = 1, and extinction in the V band is 3.1) than other nearby stars having similar metallicity. What causes this? I'm aware of why two stars...

This is just a small part of one of my problems. I need to find the luminosity of a stellar population containing 100 solar mass stars and one 20 solar mass star. I think that the 20 solar mass star will dominate, but I am not sure. Here is the formula to use: L/Lsun = (M/Msun)^3.5 I...

Hi As two stars orbit their mutual center of mass in elliptical orbits, why are their eccentricity the same? And why is it the same as the one of reduced mass around center of mass? Thanks

I've heard in the past something along the lines of "every atom in your body came from an exploding supernova". Yet, I can't see how that could be true when there is still such an abundance of hydrogen. Wouldn't any hydrogen in a star prevent it from reaching supernova stage? Assuming...

I can't seem to get any of the answers for this - please help! Two stars of equal mass M orbit a common centre. The radius of the orbit of each star is R. Assume that each of the stars has a mass equal to 1.5 solar masses (solar mass=2x10^30kg) and that the initial separation of the stars is...

When I point a camera at the sky and use the flash, it brightens up all the stars I'm looking at (not just the ones on the screen). Does anybody know why this is?

Hey guys, What method[s] do astronomers use to count the stars in the galaxy to come up with a number ?

This is probably quite a basic question but my mind has been ignited by the recent stargazing programs on the bbc so... Does every star have to be associated with a galaxy? For example, when looking through a telescope you see either individual stars or spiral galaxies - when looking at these...

First of all, I know that that very large stars tend to form black holes, and smaller stars, but still massive in comparison to our sun, tend to form neutron stars. My question is, if matter is lost when a star collapses into a black hole, but can still form one, why is it that it is a star...

Think about this, a photon travel through the universe, its path can be reflected by other objects, bended by gravity. Therefore the path would not be a straight line anymore. But very often from the TV science shows stating the distances to other stars are some some million light years. How...

Hello, I need to determine Mass-Radius relation for stars, as I prepare myslef to finish my study work. I know it's possible to evaluate it theoritically in the form - M~Rn, but I have to prove it using empirical, observational data. Making a M(R) relation diagram is indispensable so I have...

When I look at the stars in the sky with my undressed eye, they are blue. But pictures of stars taken by scientist always show them as red. Does this mean that the stars in our galaxy are fairly stationary and/or moving closer to earth? Will I find that most red shifts will be seen in stars...

Hi all, Doing a project for 1st year special topics physics module in university and we're thinking of doing the project on stars. Just wondering if anyone might know of any good literature on the sublject that we could look into as part of our research. We have until mid January to do the...

If proton decay does not occur, are neutron stars immortal? I was hearing that that was the case.

Forgive me if this has been covered already. If the universe has no center why do astronomers find the oldest stars at its edge? It seems to me that they should be everywhere.