Unanswered Questions
160 questions with no upvoted or accepted answers
10
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0
answers
215
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How well conserved is etendue in extreme gravitational lensing scenarios?
This excellent answer to Could dark matter exist in the Universe in the form of sufficiently dense objects? includes the following image and description:
Light from the background galaxy circles a ...
8
votes
1
answer
623
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Why do the Sun and gas planets rotate faster at equator than at poles?
From this site, it states that:
The Sun spins faster at its equator than at its poles.
I have also read somewhere that the gas giants (gaseous planets like Jupiter, Saturn, Uranus, and Neptune) also ...
7
votes
0
answers
256
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Get the expression of probed volume between 2 redshifts
1) I can't manage to find/justify the relation (1) below, from the common relation (2) of a volume.
2) It seems the variable r is actually the comoving distance and not comoving coordinates (with ...
5
votes
0
answers
70
views
Do all the accretion disks around a compact object (black hole or neutron star) emit astrophysical jet outflow?
Do all the accretion disks around a compact object (black hole or neutron star) emit astrophysical jet outflow? I mean is it mandatory for a jet to be emitted from an accretion disk?
If so, then why?
...
5
votes
0
answers
235
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Spectrum features of main sequence and giant stars with the same spectral type
Hence, the spectral features of the supergiant are different from those of the Sun-in accordance with the Saha equation- even though both stars are essentially at the same temperature. The pressure ...
5
votes
0
answers
100
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How do the giant planets excite the orbits of asteroids?
The giant planets, particularly Jupiter, are notorious for bringing about changes in eccentricities and inclinations of smaller bodies(asteroids and KBOs). Jupiter, in fact, throws almost all the ...
5
votes
0
answers
79
views
Obtaining the derived period of $\omega$ Canis Majoris
I have read these two papers:
On the nature of the Be phenomenon I. The case of ω Canis Majoris
Stellar and circumstellar activity of the Be star ω CMa
II. Periodic line-profile variability
In the ...
5
votes
0
answers
186
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What are some good books/online resources for astronomy problem sets?
I am currently studying for the international olympiad for astronomy and astrophysics (the syllabus can be found here: https://www.ioaastrophysics.org/syllabus/). I am currently using Carroll Ostlie's ...
5
votes
0
answers
62
views
Strength of core-envelope coupling in stars
For a star with a given Zero-Age Main Sequence (ZAMS) mass, as a function of metallicity how strongly is the star's core coupled to its envelope?
I understand that the core-envelope boundary is only (...
4
votes
0
answers
100
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What are the odds of a planet with an eclipse every time the moon rotated around the planet?
If the orbital plane of a planet and its moon were sufficiently aligned, the moon could cause a solar eclipse every lunar month. What are the odds of that happening? To answer, I would guess that one ...
4
votes
0
answers
429
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Calculation of average FWHM by PSF fitting of all the detected stars in the fits image
I need to calculate the FWHM of all the stars detected via the DaoStarFinder package/any other package by performing PSF fitting in Python. Here is the code for my detection.
...
4
votes
0
answers
54
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The Relationship between Surface Temperature and Mass of MS and Red Giant
The assumptions about the problem situation are as follows :
The red giant is in the HB at HR disgram, and it's a helium fusion situation. And in this situation, the mass of the red giant is the ...
4
votes
0
answers
60
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Explanation for Planck 2018 temperature fluctuations strongest peaks
As it can be seen from Plank 2018 Cosmic Microwave Background temperature fluctuations data-
There are 3 sharp peaks at multipole expansions $\ell \approx 250, 550, 800 $. Also as multipole expansion ...
4
votes
0
answers
54
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What happens to the non-fusion formed metals in stars?
Let’s consider a population I star of some given metallicity.
I know that depending on the type of star, different structures are possible with convection zones and radiative zones trading around ...
4
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0
answers
72
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Did astronomers "track back" solar wind switchbacks to the surface of the Sun to individual convection cells?
The new NASA Goddard video NASA's Parker Solar Probe Touches The Sun For The First Time explains that the spacecraft passed many times through "switchbacks" or kinks in the solar wind, where ...