The luminosity tag has no wiki summary.
21
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2answers
415 views
Why does laser light not affect glowing materials?
I have this childrens rubber ball which glows in the dark after it's exposed to light. I "charge" it with a flash light then play with my dogs at night. I thought to try a very intense green laser, ...
9
votes
2answers
21 views
How will the luminosity of the current very near supernova Ia “PTF 11kly” develop in the next weeks and why?
Currently there is a unique chance for amateur astronomers to observe a very near type Ia supernova, named PTF 11kly.
As standard candles are very important to measure distances in the universe, can ...
6
votes
3answers
225 views
Binary stars' apparent magnitude
If you plot the apparent magnitude of a binary system (so you are unable to see 2 distinct stars) against time, it gives a repeating 'M' effect.
(from http://accessscience.com/)
Assuming one star ...
4
votes
4answers
71 views
What objects/states of objects with absolute magnitude do we know of?
For measuring distances the knowledge of absolute magnitude or luminosity is often crucial, especially for very big distances. Unfortunately we can't measure the diameter of far distant objects and ...
4
votes
1answer
31 views
Vision vs. limiting magnitude
Does anyone know how the acuity of your vision translates to a difference in limiting magnitude?
e.g., the kind of answer I'm looking for would be
"For each factor of 2 improvement in your vision ...
3
votes
4answers
231 views
Eye sensitivity & Danger signal
Why are danger signal in red, when the eye is most sensitive to yellow-green?
You can check luminosity function for more details...
3
votes
1answer
38 views
How do you transform between theoretical Hertzsprung-Russell Diagrams and Colour-Magnitude Diagrams?
When discussing stars, theorists tend to use effective temperature $T_\text{eff}$ and luminosity $L$ (on logarithmic scales). Observers, on the other hand, usually talk about observed colours and ...
3
votes
0answers
194 views
How to integrate over rapidity for Parton Luminosities in LHC?
I want to make a comparison of parton luminosities between Tevatron and LHC. According to Factorization theorem the cross section in hadron colliders, as long as the partonic cross section has $\hat ...
2
votes
2answers
622 views
What is the luminosity per square meter hitting the Earth's surface from the Sun?
So I know that the Sun's luminosity is $3.839 \cdot 10^{26}$.
What I want is the luminosity per square meter at the Earth's surface. So this is what I have got so far:
I know the distance to the ...
2
votes
1answer
124 views
Find temperature of surface (Blackbody Radiation)
An astronomer is trying to estimate the surface temperature of a star with a radius of $5 \times 10^8\ m$ by modeling it as an ideal blackbody. The astronomer has measured the intensity of ...
2
votes
2answers
168 views
Are there formulae for calculating stellar luminosity and effective temperature as a function of age?
Is there a manageable formula or set of formulas or simple algorithms that approximate stellar luminosity and effective temperature (or radius) as a function of stellar age?
I'm aware that accurate ...
1
vote
3answers
1k views
Why is moonlight less colourful than yellow light?
Just what the title states; and this isn't an original question ...
On full-moon, moonlight is almost as bright as mid-dawn ; yet there is hardly any colour visible. This is not the case with ...
1
vote
2answers
69 views
What is the Schechter luminosity function's domain of support?
I'm trying to fit a Schechter luminosity function to some data points, but it's not clear from this definition what the domain of support of the PDF should be. I'm familiar with the standard Pareto ...
1
vote
1answer
194 views
Mass of a galaxy via Luminosity [closed]
Is there a way of calculating the mass of a galaxy, or even a nebula from the luminosity?
EDIT
I'm deleting this, and moving the question to Astronomy Stack Exchange - thanks david
1
vote
1answer
316 views
Particle Accelerator Energy and Luminosity
Both beam energy and luminosity are important for succesful particle accelerator experiments. The LHC's nominal design is for 7 TeV beams and 1E34 cm^-2 sec^-1 luminosity, while the SSC's nominal ...
1
vote
0answers
196 views
What is the relationship between Luminosity, Intensity, and Flux?
I am always confused by the terminology:
In high energy particle scattering, and in particular, in the context of collider physics, what is the relationship between luminosity, intensity and flux? ...
0
votes
0answers
36 views
Apparent, absolute, & solar luminosities [closed]
The star Sirius whose distance from the sun is 8.6 LY (light-years). The apparent luminosity has been measured
$L_{app} = 1.28 \times 10^{-11}\ \mathrm{W/cm^{-2}}$
What is the absolute luminosity ...
