Questions tagged [spectroscopy]
Questions about the measurement of light waves whereby the wavelength is classified by its position in the electromagnetic spectrum.
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What is a good resource for finding accurate apparent magnitudes stars in different filters?
I am unable to find this information online, does anyone know of a database, book, or website that contains all of the B-band, V-band, I-band etc.... apparent magnitudes for each star?
Thanks for any ...
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Determining Stellar Activity
I've been into exoplanets and the search for life for a few years now, but I'm still very much an amateur. The basics are fairly easy: habitable zone adjusted for planet/moon mass, no brown dwarves (...
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Formation of spacecraft instrumentation
List of spacecraft instruments are selected to meet a mission's science goals.
Let's take New Horizons as an example and study the composition of Pluto's atmosphere, the shape and geological ...
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Calculating intensity of moonlight per unit area
I have a photodiode that can measure intensity in picowatt to milliwatt range.
I have a telescope of 5 inch diameter. I want to calculate the intensity of moonlight received by this area? This will ...
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What spectroscopic methods are there?
It was said in a comment on this site that there are different ways spectroscopy can be achieved. I am therefore asking: What methods are available when doing spectroscopy on the composition of ...
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How accurate is astronomical spectroscopy?
We all now that green is a mixture of blue and yellow, and that purple is a mixture of red and blue. In astronomical spectroscopy the chemical composition of a planet’s atmosphere is determined, by ...
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What instruments do amateur astronomers use in their ground based telescopes in order to avoid atmospheric absorption/telluric contamination?
What instruments do amateur astronomers use in their ground based telescopes in order to avoid atmospheric absorption/telluric contamination? For example, when an astronomer observes a celestial body ...
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Obtaining Transit Spectrum for Celestial Bodies Using JWST NIRSPEC
I've recently been tasked with obtaining transit spectrum data for some fascinating celestial bodies, including Ceres, Enceladus, Ganymede, Io, and Titan. The goal is to compare their transit spectra ...
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How can I compute reasonable errors on my Gaussian fits to the observed strong optical lines of interest?
I'm fitting Gaussians to optical lines spanning from H-beta to Sulfur using Astropy's Gaussian (https://docs.astropy.org/en/latest/api/astropy.modeling.functional_models.Gaussian1D.html) model with a ...
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Star surface temperature?
I'm already familiar with using the difference in B and V magnitudes to calculate temperature, but Wikipedia (trustworthy source, I know) mentions that U-B, V-R, and R-I are also used depending on ...
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Using Gaia Passbands with L_nu coordinates
I am trying to find the coordinates of my bundles of gas on the gaia ($G, G_{bp}-G_{rp}$) hr diagram. I have its spectrum in $\nu L_\nu$ coordinates. Thus far, my attempts have mainly been to ...
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Space telescope spectroscopic data for stellar classification using Wien's law
My goal is to make a simple project which consists of classifying stars by applying Wien's displacement law.
I need public spectroscopic data about different stars from a space telescope, so that I ...
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How do nuJ(nu) units work?
I'm working with (Nublado) Cloudy, which is essentially a spectral modelling tool for stellar matter. Using the software, I model my own stellar object and obtain its continuum.
According to Hazy, ...
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How do you use Gaia Passbands to find Gbp-Grp Coordinates?
I've never used Gaia passbands, or any type of passbands before for that matter. I have a theoretical model of a stellar object, and its corresponding emissions as a function of wavelength. I'd like ...
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How do they see BOTH "anomalously cool with a significant mid-IR excess" rather than one or the other? (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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Determining the rotation curve of a galaxy via given spectroscopic data
Here is the data analysis question from IOAA-2011,
1. Weighing a galaxy: The image 8.2 shows a photograph of the spiral
galaxy NGC 7083, which lies at a distance of 40 Mpc, and image 8.3 a
fragment of ...
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How does one estimate the mass of a galaxy using the Balmer break region?
I am currently reading the recent astrophysical paper "A population of red massive galaxies ~600Myr after the Big Bang'.
In the first paragraph/abstract it mentions, "It has been difficult ...
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How has the resolution of astronomical spectrographs improved over time?
Is there something like a Moore's law for spectral resolution? Maybe a chart from which one could extrapolate?
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How do amateur astronomers do stellar spectroscopy?
This question consists of 2 parts:
How can amateur astronomers measure the spectrum of stars?
In addition to diffraction gratings, what equipment do they use (like telescopes, and the focal length ...
user47732
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Is there any open data base for raw spectroscopy data?
I'm msc. student in physics and will start my thesis in a month. We are in search of a topic with my thesis professor and we talked about many ideas. After all, "what will this give us ...
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What is meant by " elliptical galaxies stabilize due to the chaotic motion of stars"?
I read that elliptical galaxies stabilize due to the chaotic motion of stars. As I understand that means that the stellar motions are more nearly random in direction. So they perform independent ...
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What accounts for a Lyman-break for all wavelengths shorter than 91.2nm if the Lyman limit is the highest energy photon that neutral hydrogen absorbs?
From this description of Lyman-break galaxies, I don't understand how:
...radiation at higher energies than the Lyman limit at 912 Å is almost completely absorbed by neutral gas around star-forming ...
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You find yourself on a random planet in the milky way 2000 years in the future. Can you figure out where/when you are? [duplicate]
Imagine you're on a planet in a distant part of the milky way, 2000 years from now. You don't know where you are or how much time has passed. You have access to modern astronomical data and technology ...
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What data has JWST obtained of the Trappist-1 exoplanets and where is it? [duplicate]
I have been long waiting spectral data regarding the exoplanets around Trappist-1 and their atmospheres, and I was also long awaiting JWST's launch to get to know more about the system. However, now ...
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How would a person know if a planet is orbiting a binary star?
I read in Neil deGrasse Tyson's book Astrophysics for People in a Hurry that scientists can tell if a star has a planet orbiting it because the light appears to shake.
So if in the case of a binary ...
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Natural line width from absorption lines
Emission lines have a certain natural width. Due to the uncertainty principle systems that spontaneously decay or produce radiation have a fundamental energy blur, and their radiation has a ...
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How do astronomical spectrometers measure spectra from single stars separately, without contamination from all of the nearby stars?
I am currently looking into light spectrometers, and I noticed that the ones I found had a similar problem; when the light reaches the spectrometer, it mixes giving a broad range of light wavelengths.
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Where can I find datasets for all confirmed exoplanets, terrestrial exoplanets, and Super-Earth exoplanets?
The NASA Exoplanet Archive has a Planetary Systems dataset offers celestial mechanical data for 5,197 confirmed exoplanets. The Exoplanets Catalog classifies these exoplanets as terrestrial, super-...
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Different types of line broadening in stellar and galactic spectra
When analyzing stellar and galactic spectra with spectrographs, the spectral lines get broadened from the instrument. Why do the spectral lines get broadened after the light moves through the ...
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Does the luminosity of a star have the form of a Planck curve?
Figure shows the intensity of the radiant energy emitted from stars A and B over a unit time according to the wavelength. The area between the graph and the horizontal axis is S and 4S, respectively.
...
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How do astronomers calibrate the intensity scale of their spectrometers?
Discussion on Strange bump in solar spectrum taken with home-made spectrograph made me wonder: How do astronomers calibrate the intensity scale of their spectrometers? I mean, how to take in ...
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Strange bump in solar spectrum taken with home-made spectrograph
I am an astronomy teacher, and made some kind of spectrograph with a difraction grating, a 3D printed slit, water pipes and a reflex camera. With a group of students we got this picture of the solar ...
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Is it possible for us to have mistaken a few brown dwarfs and a few white dwarfs for a burning ethane-octane-oxygen planet?
Is it possible that we humans may have missclassified a handful few but not all brown dwarf stars or white dwarfs, when there really could be possibly a burning planet? Assuming a large enough planet ...
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Calculate the uncertainty in measured flux density from an integrated intensity map
I have some ALMA data, in the form of a spectral cube, which I have integrated along the velocity axis to create an integrated intensity ('moment 0') map.
The integrated intensity map shows emission ...
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Have we detected spectra of exotic atoms in stars?
I was reading this wikipedia article on positronium (a type of exotic atom) and noticed it mentioned that positronium has a spectra (of course).
So naturally this makes me wonder, have we looked at ...
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General questions about SDSS
I'm considering doing research on SDSS spectral classification (STAR, GALAXY, QSO) with machine learning for my school dissertation. Not sure if this is an appropriate place for these kinds of ...
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How can I estimate a stars surface temperature, luminosity, radius, and lifetime only knowing it's solar mass and peak wavelength? [duplicate]
For example: if a 10 solar mass star emits light at a peak wavelength of λ = 300nm.
How can I calculate a stars surface temperature, luminosity, radius, and lifetime with this infomation?
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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?
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How does instrumental dispersion work?
I am trying to understand the mathematical formulation of instrumental dispersion in galaxy and star spectra. Let $x=ln(\lambda)$. Assuming that the galaxy spectra G(x) is composed of many identical ...
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Why is infrared the ideal band to detect the earliest and most-redshifted galaxies? [duplicate]
Was infrared chosen for the James Webb Space Telescope's mission to detect the most-redshifted galaxies and stars in the universe because most detectable galactic radiation emits most strongly in the ...
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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 ...
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What does "Effective radius of [CII] line is 1.4 kpc" mean?
A recent paper (A dusty compact object bridging galaxies and quasars at cosmic dawn) describes one of their results as the "Effective radius of [CII] line" (Extended Data Table 2, p38):
I ...
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How does SDSS estimate photometric redshift of sources?
I'm looking through the data in SDSS DR 12:
...
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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 ...
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How to find the resolution of a spectrum?
I have been tasked to find the spectral resolution of some synthetic spectra (wavelength in Angstroms vs. flux) of different stars and degrade them to the resolution of observed spectra. But I am not ...
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Pulling spectral data from Hubble Telescope automatically
Libraries currently I am using: Astropy, Numpy, Matplotlib
I am looking to create a python script that pulls spectral data (wavelength vs flux chart) from the Hubble Telescope, specifically for Be ...
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When measuring the spectrum of an object at the zenith, is it better to orient the spectroscopic slit N-S of E-W?
If you were to measure the spectrum of an object while it's exactly at the zenith, how should you orient the slit of the spectrograph to minimise atmospheric dispersion? Is North-South or East-West ...
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Using optical fibers in astronomy
Why are optical fibers important in astronomy? I have read on the internet that they find applications in many fields including astronomy and this intrigued me and I would like to know what they are ...
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Why does Hubble's F850LP filter have a different shape than all the others shown in Dr. Becky's video "ALL THE DETAILS on Earendel..."?
It will take some time to read through @Pela's excellent answer to Is there a better explanation of this picture showing the very distant star "Earendel"? and to slowly ease myself into it I'...
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How are absorption cross sections calculated?
I would like to develop a more intuitive understanding of cross sections, in the context of radiative transfer.
I understand that a cross section, $\sigma_\nu$, is a measure of a given atom/molecule's ...
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