Stars Definition and 878 Threads

https://www.sciencealert.com/neutron-star-collisions-may-not-be-making-much-gold-after-all

Star magnitudes of brightness seem to use inverse logarithmic scales, is there a benefit to this? Why was this chosen, i can understand logarithmic might make it easier to interpret data in same way we do similar for earthquakes etc. But why inverse ? When i look at a HR diagram for example (...

Actually, the answer is But i am not sure why we can apply combination here. I am a little confused. I could get the answer fixing the bar 1 in each place, with this fixed, we could change the position of the other bar. That would be: First we have 7 different position After this, 6 different...

Would it be in any way physically possible for a binary star system to evaporate / explode, leaving behind two spheres of a solid metal such as gold (or an alloy), which were then rigid enough to drift together and maintain their shapes, rather than just collapsing into a larger sphere? And...

1. speed of light = 3*10^8 ms^-1 length of an Earth year=365 days*24 hours*60minutes*60seconds=3.15*1 0^7 seconds distance=speed*time 1 light year= 3*10^8 *3.15*10^7=9.46*10^15m 4.2 light years = 4.2*9.46*10^15m=3.9732*10^16m ~ 3.97*10^16m (to 3sf) 2. Intensity=power/area Power=1.4MW=1,400,000...

Why is it that some celestial bodies when observed from the Earth appear to move very little in the the sky throughout the seasons, even though the Earth in the meantime has traveled millions of miles in its orbit around the sun? From my location in Montreal, Canada, there are only very few...

So the standard explanation for star formation says we have a disk of gas collapsing into itself until a certain pressure/temperature is reached at which point the star "ignites" and pushes away the rest of the material in the disk. My thinking is, surely this pressure/temperature needed for...

Question: Is it believed a "quark star" exists within all neutron stars, or just heavier neutron stars. Do protons actually decay under this pressure (quark soup)? Are Hexaquark bosons able to remain stable beyond the limit of a proton, or would they decay at the same time of a regular...

Is it anything to do with the equation being independent of mass etc.. of the star? or to do with the Pauli exclusion principle? Any help will be much appreciated.

At midnight on may 12 2020 I saw what at first I thought was a drone zig zagging around in one spot in the sky. I looked outside at it again about ten minutes later it was doing the same thing in the same general area. I also noticed another star doing the same thing in a different part of the...

Was there a published report of exactly which stars which were supposed to be at position A but were observed at position B, etc.?

Physically speaking, why the insides of the least massive black hole should be any different from the heaviest possible neutron star?

In our galaxy, two stars, A and B, move about 20 km/s in slightly different directions to each other. The stars are about 15 light years apart. Initially, the light beams are exactly anti-parallel. Will light beams emitted from star A traveling towards light beams emitted from star B stay...

The expansion of space is about 68 km/s/Mpc, or 0.00002 km/s/light year. The radius of the sun is about 700000 km. Thus, initially ignoring additional forces, the change in radius of the sun due to the expansion of space is about 1.5*10^-9 m/sec, or 5 cm/year. I assume that this expansion is...

The question is taken from An Introduction to Modern Astrophysics by Carroll and Ostlie. I did manage to do the entire question and plot the relevant graphs but I just want to to investigate a bit more. For example I want to look at how the graph would like in the case of the Sun. I don't know...

Darwin day lecture: written in the stars: How to live happily in a deterministic universe. University of Manchester 31.1.20 Did anyone from pf attend? Or has seen him discuss this topic? Anyone interested in this topic? Too philosophical? There is a summary on his blog here...

We can not see planets or stars during the day time because of the scattering of the sunlight. But, in space, all planets and stars would be visible. Consider the situation that a rocket is going to space during the day time. At what altitude these stars or planets would become visible? On...

Here is a presentation on the discovery of two colliding neutron stars and the resulting phenomena such as gravity waves, gamma ray bursts, and synthesis of high atomic number elements. The author is a theoretical physicist who is involved in the research. He says that the neutron stars most...

Hi, so I'm currently a senior high school student and I'm doing a research project on Astrophysics. I just need help on picking a topic as I know there is a lot out there. I need a project idea that is current but not too challenging as I am limited with resources. Thanks.

Since electromagnetic radiation is emitted as electrons decay from higher to lower states of excitation, I would assume that neutron stars cannot lose energy by blackbody radiation. That would leave tidal drag and evaporation as the only ways a neutron star can lose energy...True?

Hey. Medium sized stars will turn into red giants. What about big sized stars? As far as I know they will turn into red SUPERgiants. But, will they pass through a red giant phase before it happens? In conclusion, will a big star turn firstly into a red giant and secondly into a red supergiant...

I've been thinking about this from time to time, I'll try to make this short and understandable. So we go back to the early universe within our current best model of extrapolation called the Big bang theory. In the early universe as it was expanding we have a very dense and energetic matter...

Hello! I'm attempting to find the mass of a red giant and an AGB star. I have their luminosities, radii, and the masses of their cores. I'm looking for some kind of mass-luminosity relationship. Do you know of any, or do you know of a good place to look for such equations? Thanks!

How fast are protons and electrons moving within a star?

If the light we are viewing while looking at the stars has left the origin(guess) billions of years ago. So I propose, maybe not in anyone's lifetime the end of the transmission is following the light we are absorbing today. Is that a standing wave buffered, however variable with an end if we...

The closest star tp the sun is 4 light years away. Are there any stars that are closer that are not part of a multi=star system? How close close can stars get to each other and still be independent systems?

Given that L is the luminosity of a single star and there are n stars evenly distributed throughout this thin spherical shell of radius r with thickness dr, what is the total intensity from this shell of stars? My calculations were as follows: Intensity is the power per unit area per steradian...

Hello. I'm very interested to find out more about the maximum masses of white dwarf stars and of neutron stars. Please note that while my level in this forum is Basic, I am familiar with the role that the Chandrasekhar limit has played in our understanding of white dwarves. I was therefore...

Recently a news article stated objects found in the universe have different ages, could it be that our universe is inside an already existing universe and that is why it is able to expand so easily.

A previous thread outlined the problem with a correct answer, however I don't understand where they got the formulas from. Here are the steps I've taken so far: 1. Convert 2*10^8 years to seconds = 6.3072*10^15 seconds (period,T) 2. The previous thread then went on to say you plug period and...

Is there a possibility that there are stars and planets that are composed entirely of DM? How would we detect such stars or planets? Well, I am not sure about stars, as the definition of a star depends on its fuel that it uses, I guess.

Distance is d=1/0.07 = 14.3 parsecs The Doppler shift of one star is, Δλ = 512 - 512.04 = -0.04 So the radical of the velocity of the star is = (-0.04/512) x (3.00 x 10^5 km/s) = 23.4km/s which is the same for both stars because they have the same mass. This is as far as I've got.

I've noticed that a lot of these pictures are like this. Is it something to do with the error in the machining of the lenses?

I've been doing some thinking on a sci-fi story about a colony around a Red Dwarf Star. I understand that most planets around Red Dwarf Stars, at least in the habitable zone, would be tidally locked. I created another thread to ask about ways to maintain a planetary rotation. My main question...

All, A couple of questions about planets around Red Dwarf Stars: I'm imagining a planet around a Red Dwarf Star...think Trappist-1...and want to know how I can prevent tidal locking for an Earth-sized terrestrial planet in such a star's habitable zone...say, 1/50th to 1/20th of an AU from the...

Homework Statement Assuming a Salpeter IMF with upper and lower mass limits of 0.1 and 20 M⊙ respectively, calculate: (i) the mass point at which half the mass formed in a stellar cluster lies in more massive systems and half in less massive systems. ii) the mass point at which half the...

As most people know, massive stars such as blue giant of Wolf-Rayet stars are short lived,only for a few million years.well tiny stars such as red dwarfs seems to be immortal by human’s prospective, and indeed they can live up to a trillion years! Most people thought it was only caused by the...

Homework Statement When comparing image sizes of the hotter stars with the cooler stars, do hotter stars consistently appear larger in one image and cooler stars consistently appear smaller in the other image? Why or why not? Homework Equations Stellar Spectra Classification[/B]The Attempt...

Ive been lying in bed this morning wondering about the unusual motion of stars in galaxies.The whole disc rotating like a record at the same speed.Does it mean that the effects of gravity are simply altered by speed?Much like a wonder-wall.So the faster the speed of the object,or stars,the less...

Good evening, As part of my course, I had this week two lectures about the blackbody radiation and its relation to the stars. While I do understand how to use results such as the Stefan-Boltzmann law and Wien's Law I'm lost in other parts. I think the only parts that I don't understand yet are...

I understand the process of electron transitions but I don't understand how or why these pictures are put together. If we're looking at the spectra of a star, why are this pictures shown as absorption spectra and not emission?

First post and I am not a scientist - just a curious soul. What stops a neutron star/magnetar from collapsing further into a black hole?

After much questioning and soul-searching I got my answers of why galaxies rotate, and for that I greatly thank the gurus in the forum (so I'll not forget: conservation of initial angular momentum, non-isotropic material scattering, slowdown of infalling materials and non-isotropic infalling of...

I know it's a common question but I've found no answers online so far. My professor has made a point out of saying that fusion reactions after iron and nickel do release energy but just not enough to keep the star from imploding. This didn't make sense to me. How would fission release energy if...

In modern stars, the more massive a star is, the more likely that it is powered by the CNO fusion cycle, where Carbon, Nitrogen, an Oxygen act as catalysts for creating helium from hydrogen. In stars over 1.3 solar masses, this is the primary fusion process. Below that that level it's a mix of...

Hey. I find it difficult to understand the logic and the appropriate usage of the formula: $\dbinom{N+K-1}{N}$ I don't really understand what's posed behind the scenes of that one. So I have some example for an exercise which requires the usage of this formula, but I know only to substitute...

Homework Statement Star 1 emits energy at a rate that is 2 times that of Star 2. If Star 1 also has a radius that is 3 times larger than Star 2, how do the temperatures of the stars compare? a. Star 1's temperature is 2.58 that of Star 2. b. Star 1's temperature is 3.75 that of Star 2. c...

Hi, I'm wondering if it is possible to measure radii of stars using general relativity, given its explanation of gravity as curvature of space. Thank you

I made three charts from several different sources plotting the luminosity and distance from Earth of 26 to 300 Stars. In each chart, there appears to be a correlation between a star's luminosity (in solar units) and its distance from Earth (or solar system, whichever you prefer) in light years...

https://www.sciencealert.com/matehmatical-model-of-cold-dark-matter-bose-einstein-condensate-stars Interesting read. Thoughts and comments?