Skip to main content

Questions tagged [luminosity]

Questions regarding the amount of energy produced by an object per unit of time.

Filter by
Sorted by
Tagged with
34 votes
2 answers
2k views

How could a hobbyist astronomer determine apparent magnitude of a star?

Apparent magnitude is a rather complex way to determine the brightness of a star. Quoting the introduction text from the linked to Wikipedia page: The apparent magnitude (m) of a celestial body is ...
TildalWave's user avatar
  • 6,260
12 votes
4 answers
3k views

Visible Stars in Andromeda Galaxy

So when I look at images taken of Andromeda, I see a lot of individual stars. Image by André van der Hoeven It seems to me that the actual individual stars that far away would be too small to ...
Kerry Thomas's user avatar
5 votes
2 answers
3k views

Color of planets

I am developing an astronomy software and need to know the color of each planet in the Solar System, when observed with the naked eye. I cannot find that information after googling for a while. Is ...
Jaime's user avatar
  • 153
4 votes
1 answer
1k views

Finding luminosity of a star with magnitude

I'm working on my assessment for Physics in the IB, and I'm planning to investigate stars in spiral galaxies and determine their ages. For this I'm going to use data from the SDSS (Sloan digital sky ...
user3027207's user avatar
4 votes
1 answer
2k views

Conversion of magnitudes to Jansky and MAGPHYS?

I'm a bit puzzled and not an observer, so please bear with me if I'm being stupid here. The code MAGPHYS specifies Jansky (Jy) as the input unit for flux through ...
con-f-use's user avatar
  • 235
4 votes
1 answer
1k views

Estimating a star's radius, temperature, and luminosity based on its mass

(See updated figure and description below.) I've been trying to generate ballpark estimates for the radius, temperature and luminosity of stars in the main sequence based solely on their masses (...
Bryan Wright's user avatar
2 votes
1 answer
413 views

How can I calculate the luminosity and mass of a star only knowing it's peak wavelength and it's subtended angle?

For example if a certain star subtends an angle of 32 arcminutes at the Earth’s orbit and it's light has a peak wavelength of 500 nm, how can I find the luminosity and mass of that star?
R-802's user avatar
  • 57
12 votes
1 answer
431 views

Is there a relation between mass, radius, and luminosity in deuterium-burning brown dwarfs?

I'm a worldbuilder and my setting has a lot of brown dwarfs. While I'm trying to keep my setting as science-compliant as possible, I can't seem to find any resources for brown dwarfs like there are ...
TerranAmbassador's user avatar
10 votes
1 answer
146 views

How actively is Deep Learning being used in exoplanet identification?

Papers, like this one from Google, show that Deep Learning and Machine Learning are effective in detecting exoplanets from luminosity data provided by telescopes like TESS or Kepler. These models ...
user avatar
9 votes
2 answers
4k views

What is the frequency distribution for luminosity classes in the Milky Way Galaxy?

I'm working on a game concept that does some mild simulation of realistic stellar classes and luminosities. In particular, I'd like to roughly model the general frequencies of the classes and ...
Bart Stewart's user avatar
4 votes
1 answer
1k views

What does Eddington Limit (Eddington Luminosity) Show?

We know Eddington Limit (Eddington Luminosity) is calculated with this formula: $$L_{Ed} \approx 3 * 10^4 * L_{sun} * \frac{M}{M_{sun}}$$ Example: For a black hole with $10^4 M_{sun}$, we get $$L_{...
titansarus's user avatar
4 votes
2 answers
3k views

Stellar mass of galaxies

Given the magnitudes (in the i-band) of certain galaxies, I would like to calculate their stellar mass (in terms of solar masses). So far, I have calculated their absolute magnitudes and gotten to ...
AfroBoy's user avatar
  • 43
4 votes
1 answer
277 views

If the Sun were bigger but colder, Earth would be hotter or colder?

That is the question. I know the concepts of luminosity $(L=4\pi R^2F)$ and the flow $F=\sigma· T^4$, with $T$ the temperature in its surface. But how I use that to know if the Earth would get warmer ...
Carlos Vázquez Monzón's user avatar
3 votes
2 answers
5k views

Difference between luminosity, luminous flux, and radiant flux?

I've looked this up, and was wondering the differences between them. Luminosity is the total energy emitted by a source, in watts. However, I'm confused about luminous flux and radiant flux. Since ...
user15819's user avatar
2 votes
2 answers
941 views

What would be the apparent magnitude of Betelgeuse if it were as close to Earth as Sirius?

How large and bright would Betelgeuse appear if it were as close to Earth as Sirius, before and after it goes supernova?
Justin Waters's user avatar
2 votes
1 answer
442 views

Solar luminosity proportional to $G^7$?

A book I recently purchased describes Dirac's proposed variation of Newton's G, and why that specific proposal wouldn't work because the earth would have been too hot for the known history of life. A ...
stellatedHexahedron's user avatar
1 vote
1 answer
108 views

How does the Eddington limit make the gravitational field of stars asymmetric?

This answer to Is the gravitational field of the sun uniform? says: Very large stars are asymmetric due to being close to the Eddington limit. The Sun is too small of a star to have the kind of ...
uhoh's user avatar
  • 30.6k