All Questions
Tagged with astronomy spectroscopy
71
questions
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1
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26
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What is emission line ratio?
As the header stated, what exactly is the 'emission line ratio'? Like, [O III]/Hβ or [Ne V]/[Ne II]. Recently I've been reading some research papers in astronomy and astrophysics pertaining to ...
2
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1
answer
35
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Advantage of a single large telescope over many small ones for optical/infrared spectroscopy?
In a thought experiment where we would like to do optical/infrared spectroscopy on distant galaxies, and in which we would like to increase as much as possible the resolution of the spectroscopy (...
- 1,109
4
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2
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380
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Underestimation of peak wavelength by Wien's law for stellar spectra
I plotted some simulated stellar emission spectrums from PHOENIX which also each came with their respective effective temperatures. With the effective temperatures, I used Wien's law to estimate the ...
- 143
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22
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Stellar classification: Luminosity class
So in the astrophysics textbook by Carrol and Ostlie, when the luminosity class is discussed, it has such a sentence "The ratio of the strengths of two closely spaced lines is often employed to ...
- 161
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96
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Fine structure of the hydrogen atom
How is the fine structure of Hydrogen of importance in the astronomical observations? For example: I know that 21 cm can penetrate the cloud of interstellar dust and hence allows the mapping of the ...
- 101
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2
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971
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The Resolving Power of a spectrometer
I can't understand one thing in the definition of the resolving power of a spectrometer:
Let the resolving power be defined as: $R=\frac{\lambda}{\Delta \lambda}$ where $\Delta \lambda$ is the ...
- 941
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29
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How to obtain exoplanets transmission spectra from JWST's NIRISS data of WASP96?
I was having a look at JWST's NIRISS data of WASP96 (specifically at the x1dints fits file which should be already calibrated). From this, I would like to obtain a result in a fashion similar to the ...
- 69
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2
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366
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How can we extract the Doppler shift of supernovae?
My understanding is that supernovae are used as standard candles, whose spectral lines indicate the recession velocity of the host galaxy.
But the material from the supernova is ejected at a ...
- 9,500
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37
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Total brightness from emission spectra?
Some background: I'm looking to analyze stars through a telescope; I'd like get both the visual spectrum and the brightness of each target. I'd also like to have to build/carry as few instruments as I ...
- 11
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1
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471
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Determine Mass of a Star Using Electromagnetic Spectra
How do astronomers determine the mass of a star using spectra. In this answer here https://physics.stackexchange.com/a/503515, they state that the mass of a star is extracted from its spectrum and ...
- 11
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2
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159
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How is that possible to isolate one particular star light from the others?
We can analyze distant stars by investigating the spectrum of their light. But we have billions of stars in the sky, and I wonder how it is possible to isolate the light of one particular star from ...
- 123
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3
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How can spectroscopy be used to find the composition of exoplanet atmospheres?
How can astronomers use light spectroscopy to measure the composition of different planets when they can't directly image the planet because the star that they are orbiting is so much bigger and ...
- 117
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1
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35
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Terminology: "3σ detection over the continuum"
I am reading a research paper and they use the expression:
"This is a weak signal, i.e. 3-4σ detection over the continuum".
I saw this sentence in a lot of papers, but I can not find what ...
- 447
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2
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32
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How is the source size estimated using the variability of the spectrum?
When reading some astrophysical papers I saw things like this:
The sources are variable on very short timescales, implying a compact emission region.
How can we conclude or measure the source size, ...
- 55
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2
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282
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Displaced spectral lines of a star
Why do we see the lines in a star spectra displaced from the wavelength they belong to and so we need to calibrate the spectra ?
Is it only because the relative motion of star and earth ?
