Questions tagged [black-body]
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27 questions
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Calculating luminosity from SED
I have an SED with wavelength in microns, and fluxes in mJy. I try the following code but my derived luminosity is a factor of 2 less (I should get 2.5e-3 L_sun). I think I am converting the fluxes ...
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Does most of the Sun's energy and light come from its black-body temperature, due to its massive size alone? Constant crashing of particles?
Stars have to be a certain size to initiate fusion to begin with, correct?
Isn't this why brown dwarfs are considered 'failed stars'?
But wouldn't the Sun (and other stars with sufficient mass, like ...
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How to calculate a part of a spectrum from another part of it?
I have some radio data (flux) in 1.4 GHZ and also distance data. I calculated the luminosity for this frequency. Here, i want to use power-law and/or blackbody relation to calculate possible ...
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Why does the CMB conform to black-body formula for 2.71 degrees, when it's the stretched emission at a far hotter temp?
Physicist Chad Orzel in "Einstein's Legacy" discusses Planck's Black-Body formula, stating that it fits perfectly to everything we see, from toasters to stars. Fine. Then he says it ...
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Cooling timescale for an interstellar dust grain
I would like to estimate the cooling timescale for an interstellar dust grain, starting at 200K, down to 100 K.
The equation I have come up with is:
$\displaystyle t_{cooling} = \frac{mC\Delta T}{Q_{...
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Back when the CMB was predominantly in the visible spectrum, would it have been visible to the naked eye?
The CMB is a near-perfect black-body spectrum, and assuming this has been true since the de-coupling, we should have been able to see the glow. In fact, at a certain point, it should have been almost ...
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How can a black hole stop light from being emitted when all observers see light traveling at the same speed? [duplicate]
Quite literally every science show talks about black holes with a similar phrase: so dense that nothing, not even light, can escape.
Let's say I am in space a safe distance from an object. I drop an ...
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How far can a star's visual colour deviate from black body radiation?
The primary driver of a star's colour is its temperature, by way of black-body radiation.
Black body radiation restricts stellar colour to a narrow slice of the full RGB spectrum.
However, all stars ...
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At high temperatures, do planets glow like blackbodies?
I've been messing around in Universe Sandbox for a while and noticed that as a planet heats up, it glows like a blackbody starting at ~4000 K. Is the simulation here accurate, or do very hot planets ...
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What does the Reddening line represents in this U-B vs B-V plot?
The plot is from this paper (pg-8).
They have also talked(in the same paper) about how central stars from galactic longitude range $20^\circ-80^\circ$ will have a very unusual Reddening line (pg-9). ...
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Does photon capture in a black hole (or any other "very compact" object) reduce the luminosity/photon flux from its self isotropic emission?
I don't know if this is even a feasible question or if I have a point in asking so.
Let's say we can model the radiation coming from a very compact object, such as a BH with an accretion disc or any ...
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Blackbody curve in RGB for objects less than 1500 K?
We know the colors of stars that have a temperature greater than 1000-1500 K, shown here. However, I am wondering about those stars/brown dwarfs with surface temperatures of less than 1500 K. Is there ...
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What is the RGB curve for blackbodies?
I created a program to convert the temperature (in Kelvin) of a blackbody to RGB color. However, it is slightly inaccurate, and the deviations increase for values greater than 10000K and less than ...
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Why is a black hole's Hawking radiation temperature inversely proportional to its mass/size?
As a black hole shrinks in volume and mass, shouldn't its temperature get lower? Shouldn't it evaporate more slowly?
Naively, (very naively), I think that with a smaller surface area (as per its ...
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What was the energy/wavelength/frequency of the CMB when first emitted/released?
Given the z redshift of 1089, and the temperature difference between then and now of about 1089, I tried scaling the ev, freq. and wavelength by 1089....
Is that right?
I get a freq. of about 240 ...
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How to convert from Black body intensity to MJy/sr?
How does one convert from ${\rm ergs\cdot cm^{-2}\cdot s^{-1} \cdot sr^{-1}\cdot Hz^{-1}}$ to ${\rm MJy \cdot sr^{-1}}$
and from ${\rm ergs\cdot cm^{-2}\cdot s^{-1} \cdot sr^{-1}\cdot cm^{-1}}$ to ${\...
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How is Cosmic Microwave Background's temperature measured?
How do Cosmic Microwave Background missions/telescopes measure CMB temperatures? I understand that CMB has Planck's spectrum. So I was thinking one strategy could be to measure the spectral radiance ...
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Questions about Planck’s law
Two questions:
I read online that all objects emit the majority of their thermal radiation in the radio, and that this emission increases with temperature. Does this mean that all glowing bodies emit ...
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Trouble with plotting a graph for the Planck function
Here is my problem statement:
For a temperature of $7.3 \times 10^5 \ \text{K}$, make a graph of the Plank function (Eq. 3.24), plotting $\log_{10}{\nu} B_\nu(T)$ vs $\log_{10} \nu$ for $\log_{10} \...
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How to Distinguish between Temperature and Doppler effect using Black-body radiation?
I understand that the radiation of a body can be described using the curve for black-body radiation. In the sense that a hotter body will be blue shifted and a cooler body will be red shifted.
The ...
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Can hawking radiation be eaten by another blackhole?
Just a theory, from this video. At last, only the black holes are gonna exist and even they'll decay because of hawkings radiation.
As black holes emit hawkings radiation, then if one emits it, ...
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Strange behaviour of black holes [duplicate]
We know black holes emit streams of radiation ,also recently discovered that they emit visible light when they eat any nearby matter .
"We find that activity in the vicinity of a black hole ...
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Where can we find astronomical real world data (spectral radiance and wavelength particularly) of a star?
I have my college project and I thought of finding the temperature of a star with the black-body curve of star but i need real data.
I searched but can't find the thing what I want. all I am getting ...
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What does a black dwarf look like?
A black dwarf is a hypothetical object that is the end result of the cooling of a white dwarf. None yet exist, because there hasn't been enough time in the age of the universe for them to cool down ...
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Future redshifting and effect on the 'pitch' of CMB radiation
After discovering this question exploring the sound of a blackbody, I started wondering about the sound of the Cosmic Microwave Background radiation from the Big Bang, specifically what the current ...
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In what manner is the spectrum of a black body really a continuum?
Usually they say the spectrum of a black body is a continuum and emits radiation at every frequency. Is it really a continuum like a line or are there (small) intervals?
For example, can a body emit ...
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