Unanswered Questions
84 questions with no upvoted or accepted answers
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Relationships between G magnitude, Johnson V magnitude, and spectral type of stars?
I'm simulating a population of binary stars for a summer research project. I'm adding uncertainties to my simulated observables such as angular position and radial (line of sight) velocity. I'm using ...
- 5,636
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60
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Error of bisector method
How to determine the error of bisector velocity span? I have found the article below, but I do not know what all quantities mean. What is the number of lines in the mask? How to find out x? How to ...
- 18.7k
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103
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H alpha - double peak (Be star)
What is the double peak in this case, please? What does the third mean? Many thanks
- 17.6k
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36
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Any examples of a gas object temperature from Doppler broadening along one axis turning out to be wrong because velocity spread was not isotropic?
Discussions under Mass of the stellar cluster (not the whole galaxy) lead me to mention that when an actual temperature is inferred from a Doppler-broadened line profile (rather than just a linewidth ...
- 30.7k
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Astrophysical particle spectroscopy; narrow-line particle sources (charged or uncharged) for things other than photons? Have any been detected?
Is Cosmic Ray Astronomy a thing?
Is there an equivalent of the red shift effect for cosmic rays?
have got me thinking and under this answer I've commented:
That's a good point; there aren't as many ...
- 30.7k
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Are falling evaporating bodies (FEBs) and exocomets the same thing? How does one know they're falling and evaporating?
Looking for a (short) list of comets with heliocentric escape velocity I stumbled upon Wikipedia's exocoments which like exoplanets, are bound to other stars. I should have been looking for "...
- 30.7k
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558
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How to convert between spectra given in terms of velocity (km/s) to wavelength spectra?
I have H alpha spectra of H II regions in our galaxy. In the paper, the x-axis is in units of km/s and the corresponding line width as well. From this, how can I get equivalent width of the H alpha ...
- 4,800
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Absorption line in quasar spectrum
I have quasar spectrum which includes emission and absorption lines. I need to find absorption lines in between 2 wavelength. How can I do it with coding?
- 8,452
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429
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How to calculate Equivalent Width of a spectrum with continuum at 0
I am trying to calculate the Equivalent Width of emission lines of a spectrum whose continuum is at 0, making the calculation of the EW impossible.
I have the spectrum of a transient in a galaxy, so ...
- 11
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Does Nickel show up in spectra of Nova?
Does a nova, not a supernova, get hot enough that nickel is produced despite its formation by fusion being an endothermic reaction? If nickel is made, does it make it out of the star into the nebula?
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- 4,528
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Relation between oscillator strengths $\log{gf}$ and the Einstein $A$-coefficient, rotational quantum number,
I'm analyzing the spectra of M dwarfs. Some authors characterize the lines with the oscillator strengths $\log{gf}$ while others follow different paths with the Einstein $A$-coefficient. I would like ...
- 381
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43
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what/how do we mean/derive statistical equilibrium equation of certain energy levels?
While reading the research paper "Excitation of the Fe XIII Spectrum in the Solar Corona" by D.R. Flower and G. Pineau des Forets in the summary I found the concept of statistical equilibrium equation ...
- 30.7k
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Polarization of an emission line
Say I have a flux density spectrum of a galaxy, as well as polarization spectra for the object in U, Q, and P. I want to find the polarization of some emission line in the spectrum. First, I can fit a ...
- 303
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123
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How do you fit a model SED to an observed galaxy spectrum with photometric data?
I have a spectrum of a galaxy from HST data and SDSS data (resulting in a nearly continuous SED from the FUV~1000 Angstroms through infrared). I have created a model SED with the galaxy simulation ...
- 303
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527
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Conversion factors for flux
I have a flux value in the infrared band of 8 mJy at a wavelength of 80 microns that I want to translate into X-ray conventional ...
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