Unanswered Questions
227 questions with no upvoted or accepted answers
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Which is brighter, starlight or the CMB?
Which do we receive more energy from, the CMB or starlight? (Not including the sun of course.)
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What are the primary astrophysical implications of a proposed mass of about 11 M⊙ for the SN 2023ixf progenitor?
The abstract of the arXiv preprint SN 2023ixf in Messier 101: A Variable Red Supergiant as the Progenitor Candidate to a Type II Supernova (itself recently "discovered" in the observatory) ...
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Trying to understand how to properly implement this equation to a healpix map
So i am working on reproducing a paper (Secrest, N. J., von Hausegger, S., Rameez, M., Mohayaee, R., Sarkar, S., & Colin, J. (2021). A test of the cosmological principle with quasars. The ...
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How much would you weigh at the equator of the fastest spinning pulsar?
Assuming you have a mass of 70 kg, what would your weight be on the equator of PSR J1748−2446ad?
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Heaviest star in universe
Using the estimated age of the universe, can we calculate the heaviest star in the universe using normal fusion reaction rate of our sun? Assuming the star did not die.
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What are the exact properties and evolution of a star with 1.23 Solar masses?
I'm working on a project where the star at the centre of the planetary system is 1.23 Solar masses. What would it's properties and evolutionary track be (i.e. main sequence lifespan, length of the red ...
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Where to find all spectroscopic data about 28 CMa?
I am searching all available spectroscopic data (and particularly wavelength interval) of 28 CMa in the constellation Canis Majoris to measure radial velocities. Which database should I use?
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Stellar temperature ~ frequency relationship?
According to Wikipedia, 76% of all stars are of spectral type M, 12% are of K, 7.5% are of G, etc. (see this section on Stellar Classification). This is very helpful, but is too vague, as the ...
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What is sonic transition of an astrophysical fluid?
My notes mention sonic transition of a fluid. Is it where the speed of the fluid elements cross the speed of sound in the medium they are located?
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Where can I find galaxy spectra (in the form of FITS files)?
I know there's SDSS and I tried searching for the spectra through the navigate and explore tool under CAS as well as by using RA/Dec coordinates under SAS, but every single time it comes out with 0 ...
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shape of gas and shape of stars
How does the shape of the gas and shape of stars change as the galaxy ages? Does there exists any such formula which relates the shape/volume with the time?
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Setting specific CENTER coordinates coordinate in SWARP
The SWARP Documentation specifies that we first set the CENTER_TYPE to MANUAL and then in the CENTER parameter we specify either one of the equatorial coordinates (RA, Dec). This is specified in the ...
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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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Theoretical values of radius and mass of O9.5 II star
Where to find please theoretical values of radius and mass of O9.5 II star?
I mean something like in this article. However, there are only O I, O III and O V stars in this article.
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How is V1057 Cygni supposed to go from K type dwarf to F type giant?
FU Orionis variables are protostars that go through massive outbursts that drastically change the star's spectral type and magnitude. With the star V1057 Cygni, this star was known to go from a K type ...
