diff --git a/Equivalent_Width_Spectroscopy_Lab_Student.ipynb b/Equivalent_Width_Spectroscopy_Lab_Student.ipynb index 23c4499..aaccfe7 100644 --- a/Equivalent_Width_Spectroscopy_Lab_Student.ipynb +++ b/Equivalent_Width_Spectroscopy_Lab_Student.ipynb @@ -6,7 +6,7 @@ "name": "Equivalent Width Spectroscopy Lab.ipynb", "provenance": [], "collapsed_sections": [], - "authorship_tag": "ABX9TyONs1OwtMWsReZJlVKDxvnZ", + "authorship_tag": "ABX9TyNlO56SqVT3Fk6TpdJyHmni", "include_colab_link": true }, "kernelspec": { @@ -67,7 +67,7 @@ "# This line of Python will print the message when you hit the play button.\n", "print(message)" ], - "execution_count": 1, + "execution_count": null, "outputs": [ { "output_type": "stream", @@ -85,8 +85,15 @@ }, "source": [ "## Who are you?\n", - "This is a text block. It allows you to write text but doesn't run Python code. Go ahead and put all your information in this block so we know who is completing the assignment.\n", - "\n", + "This is a text block. It allows you to write text but doesn't run Python code. Go ahead and put all your information in this block so we know who is completing the assignment." + ] + }, + { + "cell_type": "markdown", + "metadata": { + "id": "exYOOvxZpt6k" + }, + "source": [ "**Double click here and put your name (s), the date, and course information.**\n", "\n", "Answer:" @@ -107,7 +114,7 @@ "id": "Yx0JvZDqNfOz" }, "source": [ - "\n", + "
Figure 1 - Visible light spectrum of the sun. (Fraknoi et al., 2017)\n", "\n", "Light from objects in space can tell us a lot about the object. If we use that light to do spectroscopy, we can determine the temperature of the object, the nature and speed of its motion, and we can find out what its made of. We are exploring the chemical makeup of some stars in this project.\n", "\n", @@ -120,10 +127,17 @@ "id": "5cv6pQ4IO_MF" }, "source": [ - "## Question 0\n", - "**Double click here to answer. How does a spectrometer or spectrograph turn starlight into colors? You can use the link above for a hint.**\n", - "\n", - "Answer: " + "## Question 1\n", + "**How does a spectrometer or spectrograph turn starlight into colors? You can use the link above for a hint.**" + ] + }, + { + "cell_type": "markdown", + "metadata": { + "id": "d1vRRmBhqF5O" + }, + "source": [ + "Double click here to answer:" ] }, { @@ -136,7 +150,7 @@ "\n", "The spectra we are analyzing were collected using the historic Otto Struve Telescope at McDonald Observatory with the Sandiford Echelle Spectrometer.\n", "\n", - "" + "
Figure 2 - Sandiford Echelle Spectrograph at cassegrain focus on Otto Struve Telescope, summer 2019.\n" ] }, { @@ -146,9 +160,10 @@ }, "source": [ "## What is a spectrum?\n", - "This is the spectrum of a star. The y-axis represents the amount of light and the x-axis represents the wavelength of the particular feature. Spectroscopy can tell us objects in space. For instance, using nothing more than the light from the star and some math, you can get a sense of the relative amount of a particular element in a star's atmosphere by looking at the absorption line. That is what we are doing today.\n", + "This is the spectrum of a star. The y-axis represents the amount of light and the x-axis represents the wavelength of the particular feature. Spectroscopy can tell us about objects in space. For instance, using nothing more than the light from the star and some math, you can get a sense of the relative amount of a particular element in a star's atmosphere by looking at the absorption line. That is what we are doing today.\n", + "\n", + "
Figure 3 - IRAF spectrum plot for star HD 141531 from summer 2019 observing run.\n", "\n", - "\n", "\n", "When one star has more of an element in its atmosphere than another, the absorption line or dips in in the light will be deeper because those atoms took some of the light leaving the star and absorbed it so those photons won't make it to us.\n", "\n", @@ -166,11 +181,13 @@ "# Searching for Europium\n", "\n", "Elements beyond lithium on the periodic table are produced by stars. Some of the heaviest elements come from the most awesome stellar explosions. Supernovae and kilonovae can make lots of the heavy atoms all at once. After the debris from those explosions get swept up in new stars, these atoms can be found floating around in the newer star.\n", - "\n", + "
Figure 4 - A stellar nucleosynthesis version of the periodic table of the elements. (Wikimedia, 2020)\n", + "\n", "\n", "These spectra we are analyzing here are part of a stellar survey looking for the presence of the lathanide elements. One element, europium, has a signature that can seen using spectroscopy.\n", "\n", - "\n", + "
Figure 5 - Metallicity constraints for stellar observational targets. (Sneden, 2019)\n", + "\n", "\n", "5 stellar spectra are stored in a Google spreadsheet and you are going to use code to access, analyze, and plot the data. You will compare how much europium these stars have by using the nickel absorption line as a measuring stick." ] @@ -202,7 +219,7 @@ "from oauth2client.client import GoogleCredentials\n", "gc = gspread.authorize(GoogleCredentials.get_application_default())" ], - "execution_count": 2, + "execution_count": null, "outputs": [] }, { @@ -223,7 +240,7 @@ "# Put the URL for your copy of the Google Sheet here.\n", "wb = gc.open_by_url('https://docs.google.com/spreadsheets/d/1ns1t3TZBdeFexAfBa6DVSUkqKW6g7Gz2I48RrMmRwbM/edit#gid=1134205444')" ], - "execution_count": 3, + "execution_count": null, "outputs": [] }, { @@ -257,7 +274,7 @@ "# Install SpecUtils usin pip\n", "!pip install specutils" ], - "execution_count": 4, + "execution_count": null, "outputs": [ { "output_type": "stream", @@ -321,7 +338,7 @@ "from matplotlib.collections import PatchCollection\n", "from matplotlib.patches import Rectangle" ], - "execution_count": 5, + "execution_count": null, "outputs": [] }, { @@ -337,7 +354,7 @@ "quantity_support()\n", "from astropy.utils.data import download_file" ], - "execution_count": 6, + "execution_count": null, "outputs": [] }, { @@ -355,14 +372,13 @@ "id": "gfqe8qRGuSjV" }, "source": [ - "\n", "# Here we access the parts of specutils we'll need.\n", "from specutils import Spectrum1D\n", "from specutils import SpectralRegion\n", "from specutils.analysis import equivalent_width\n", "from specutils.analysis import fwhm" ], - "execution_count": 7, + "execution_count": null, "outputs": [] }, { @@ -408,7 +424,7 @@ "\n", "# Put the code to fill the other wave, flux, and label variables here" ], - "execution_count": 8, + "execution_count": null, "outputs": [] }, { @@ -417,11 +433,18 @@ "id": "tNYRUnLOdDdA" }, "source": [ - "## Question 1\n", - "**Double click to answer the question. If these spectra run from 6643 Å to 6646 Å, what color from the visible spectrum would the light appear? You can assume the visible spectrum runs from 300 nm to 700 nm. Note: 10 nm = 1 Å.**\n", + "## Question 2\n", + "**If these spectra run from 6643 Å to 6646 Å, what color from the visible spectrum would the light appear? You can assume the visible spectrum runs from 3000 Å to 7000 Å.**\n" + ] + }, + { + "cell_type": "markdown", + "metadata": { + "id": "n-295bIwsdYH" + }, + "source": [ "\n", - "Answer:\n", - "\n" + "Double click here to answer:\n" ] }, { @@ -434,23 +457,29 @@ ] }, { - "cell_type": "code", + "cell_type": "markdown", "metadata": { - "id": "sH7PvaEYAVXo" + "id": "o6jLe5fAydUD" }, "source": [ - "\"\"\"\n", " This function interpolates a spectrum to make them smoother when plotting. \n", " You won't need to change anything here but you will need to run the block\n", - " so the notebook learns this function and can use it later.\n", - "\"\"\"\n", + " so the notebook learns this function and can use it later." + ] + }, + { + "cell_type": "code", + "metadata": { + "id": "sH7PvaEYAVXo" + }, + "source": [ "def interp(w, f):\n", " wInterp = np.linspace(w.min(),w.max(), 300) \n", " spl = make_interp_spline(w, f)\n", " fInterp = spl(wInterp)\n", " return wInterp, fInterp" ], - "execution_count": 9, + "execution_count": null, "outputs": [] }, { @@ -474,7 +503,7 @@ "# Interpolate the data for smoother plots\n", "wave1, flux1 = interp(wave1,flux1)" ], - "execution_count": 10, + "execution_count": null, "outputs": [] }, { @@ -487,7 +516,7 @@ "flux1 = flux1*u.Unit('erg cm-2 s-1 AA-1') \n", "wave1 = wave1*u.AA" ], - "execution_count": 11, + "execution_count": null, "outputs": [] }, { @@ -537,7 +566,7 @@ "# Display all the things we've setup.\n", "plt.show()" ], - "execution_count": 12, + "execution_count": null, "outputs": [ { "output_type": "display_data", @@ -560,10 +589,17 @@ "id": "Z59LtAp6fezr" }, "source": [ - "## Question 2\n", - "**Double click to answer the question. What features do you see for the spectra? How many major features do you sees? How are spectra similar and how are they different? Remember to describe how the plots are shaped relative to one another.**\n", - "\n", - "Answer: " + "## Question 3\n", + "**What features do you see for the spectra? How many major features do you sees? How are spectra similar and how are they different? Remember to describe how the plots are shaped relative to one another.**" + ] + }, + { + "cell_type": "markdown", + "metadata": { + "id": "_wyeDqJptUES" + }, + "source": [ + "Double click here to answer:" ] }, { @@ -572,19 +608,17 @@ "id": "HvyME5fAgN5o" }, "source": [ - "## Question 3\n", - "**Double click to answer the question. What do the dips represent? What does the wavelength of the lowest point in the dip represent? Hint: think how this is related to how a hydrogen atom can emit and absorb certain photons.**\n", - "\n", - "Answer: " + "## Question 4\n", + "**What do the dips represent? What does the wavelength of the lowest point in the dip represent? Hint: think how this is related to how a hydrogen atom can emit and absorb certain photons. [How do spectral lines form?](https://openstax.org/books/astronomy/pages/5-5-formation-of-spectral-lines)**" ] }, { "cell_type": "markdown", "metadata": { - "id": "cyF7SUeCWetQ" + "id": "s-U2-dzPtZrb" }, "source": [ - "Hint: [How do spectral lines form?](https://openstax.org/books/astronomy/pages/5-5-formation-of-spectral-lines)" + "Double click here to answer:" ] }, { @@ -606,7 +640,7 @@ "\n", "$ W_{\\lambda}\\propto\\ Nhf\\lambda^2 $\n", "\n", - "The equivalent width $ W_{\\lambda} $ varies as the number of atoms of that element, $ N $." + "The equivalent width $ W_{\\lambda} $ varies as the number of atoms of that element, $ N $. The product $ hf $ is Planck's constant times the frequency of the absorption feature. $ \\lambda $ is the wavelength of the of the absorption feature. This strange notation is common for stellar spectroscopy." ] }, { @@ -662,7 +696,7 @@ "\n", "plt.show()" ], - "execution_count": 13, + "execution_count": null, "outputs": [ { "output_type": "display_data", @@ -706,30 +740,19 @@ "id": "yCCNi44RDZ4q" }, "source": [ - "## Question 4\n", - "**Double click to answer the question. Choose of the plots you made and estimate by eye the equivalent width for the Ni I line near 6643 Å. You need to estimate the depth of the curve below 1. Then divide that by 2 and find the left and right wavelengths where the curve has that same flux below 1. Multiply these numbers. The units are Å since the flux here is relative and has no units.**\n", - "\n", - "Answer: \n", - "* What star did you choose? \n", - "* What is the max absorption below 1? \n", - "* What is the half-max? \n", - "* At what 2 wavelengths does the flux curve pass through the half-max point? \n", - "* What is the equivalent width?\n", - "(left wavelength - right wavelength)*(maximum absorption below 1)" + "## Question 5\n", + "**Choose one of the plots you made and estimate by eye the equivalent width for the Ni I line near 6643 Å. You need to estimate the depth of the curve below 1. Then divide that by 2 and find the left and right wavelengths where the curve has that same flux below 1. Multiply these numbers. The units are Å since the flux here is relative and has no units.**" ] }, { "cell_type": "markdown", "metadata": { - "id": "sPGwjPejC-OS" + "id": "mECmI61_tiYR" }, "source": [ - "## Question 5\n", - "**Double click to answer the question. Choose one of the plots you made and estimate the equivalent width for the Ni I line near 6643 Å. You need to estimate the depth of the curve below 1. Then divide that by 2 and find the left and right wavelengths where the curve has that same flux below 1. Multiply these numbers. The units are Å since the flux here is relative and has no units.**\n", - "\n", - "Answer: \n", - "* What star did you choose? \n", - "* What is the max absorption below 1? \n", + "Double click here to answer: \n", + "* What star did you choose?\n", + "* What is the max absorption below 1?\n", "* What is the half-max? \n", "* At what 2 wavelengths does the flux curve pass through the half-max point? \n", "* What is the equivalent width?\n", @@ -764,7 +787,7 @@ "source": [ "spec1 = Spectrum1D(spectral_axis=wave1, flux=flux1)" ], - "execution_count": 14, + "execution_count": null, "outputs": [] }, { @@ -800,7 +823,7 @@ "print('EW Ni I 6643A\\tEW Eu II 6645 A\\tEu/Ni\\tName') # Print a header row\n", "print(str(ni1)+'\\t'+str(eu1)+'\\t'+str(r1)+'\\t'+label1) # Print for target 1" ], - "execution_count": 15, + "execution_count": null, "outputs": [ { "output_type": "stream", @@ -819,9 +842,16 @@ }, "source": [ "## Question 6\n", - "**Double click here to answer. Compare your calculation done by hand to that done by the code. Were you close? Why would we compare the 2 calculations? What could cause the calculation by hand and that from the computer to be different?**\n", - "\n", - "Answer:" + "**Compare your calculation done by hand to that done by the code. Were you close? Why would we compare the 2 calculations? What could cause the calculation by hand and that from the computer to be different?**" + ] + }, + { + "cell_type": "markdown", + "metadata": { + "id": "lnq-S8ThuNYe" + }, + "source": [ + "Double click here to answer:" ] }, { @@ -832,7 +862,8 @@ "source": [ "# Stellar Nucleosythesis\n", "\n", - "![https://physics.aps.org/articles/v9/s66](https://physics.aps.org/assets/96e56287-2b25-482b-b075-894adc7b2b10/es66_1.png)\n", + "![https://physics.aps.org/articles/v9/s66](https://physics.aps.org/assets/96e56287-2b25-482b-b075-894adc7b2b10/es66_1.png)
Figure 6 - Artist conception of neutron capture event. (Stonebreaker, 2016)\n", + "\n", "\n", "Heavy elements can be formed when neutrons smash into existing elements. The result is a left over proton in the nuclues. Adding a proton to a nucleus means you changed from atom to another. There are 2 types of stellar events that cause the rapid formation of elements: stellar explosions like a supernova and stellar mergers." ] @@ -849,7 +880,7 @@ "Sometimes a random neutron inside a star slams into a nucleus and makes a heavier element. This process is rare so it takes a long time to build up an element this way. That's why it's called the slow or s-process. \n", "\n", "Europium is thought to mainly come from the r-process, although some europium comes from the s-process.\n", - "" + "
Figure 7 - Neutron capture decay pathway through s-process for xenon. (Sneden et al., 2008)\n" ] }, { @@ -859,9 +890,16 @@ }, "source": [ "## Question 7\n", - "**Double click here to answer. If our target stars have comparable amounts of nickel, what measure should you use based on the results from the code? Rank the stars from most europium detected to least europium detected.**\n", - "\n", - "Answer:" + "**If our target stars have comparable amounts of nickel, what measure should you use based on the results from the code? Rank the stars from most europium detected to least europium detected.**" + ] + }, + { + "cell_type": "markdown", + "metadata": { + "id": "sj_0rDoKuXJ-" + }, + "source": [ + "Double click here to answer:" ] }, { @@ -871,9 +909,16 @@ }, "source": [ "## Question 8\n", - "**Double click here to answer. These stars all have very similar properties like mass and temperature. Why do they have varying amounts of europium? You should be able to list 3 physical processes by which europium atoms ended up in these stars.**\n", - "\n", - "Answer: " + "**These stars all have very similar properties like mass and temperature. Why do they have varying amounts of europium? You should be able to list 3 physical processes by which europium atoms ended up in these stars.**\n" + ] + }, + { + "cell_type": "markdown", + "metadata": { + "id": "BDLENLD5uuAf" + }, + "source": [ + "Double click here to answer:" ] }, { @@ -884,7 +929,8 @@ "source": [ "# HR Diagram\n", "Astronomers use the Hertzsprung-Russell Diagram to compare groups of stars and to look for patterns.\n", - "\n", + "
Figure 8 - H-R diagram for a selected sample of stars. (Fraknoi et al., 2017)\n", + "\n", "\n", "Here is a classic example of an HR diagram with some of the known groupings labeled.\n", "\n", @@ -897,7 +943,8 @@ "id": "_UkPn14yuvWb" }, "source": [ - "![HR Diagram](http://www.jimmynewland.com/wp/wp-content/uploads/2020/08/Screen-Shot-2020-08-12-at-5.07.18-PM.png)\n", + "![HR Diagram](http://www.jimmynewland.com/wp/wp-content/uploads/2020/08/Screen-Shot-2020-08-12-at-5.07.18-PM.png)
Figure 9 - H-R diagram for nearby stars, the sun, and our stellar targets.\n", + "\n", "\n", "Here is an HR diagram of some of the nearest stars with our sun and out targets stars also plotted. The main sequence is the grouping of stars running from upper left to lower right and the red giant branch runs from the main sequence off to the upper right." ] @@ -909,9 +956,16 @@ }, "source": [ "## Question 9\n", - "**Double click here to answer. Using the HR diagram, can you put the results of the EW measurements in context? Are all the targets the same age? What role could the s-process have for these stars?**\n", - "\n", - "Answer:" + "**Using the HR diagram, can you put the results of the EW measurements in context? Are all the targets the same age? What role could the s-process have for these stars?**" + ] + }, + { + "cell_type": "markdown", + "metadata": { + "id": "07ldeiM6uz_1" + }, + "source": [ + "Double click to answer:" ] }, { @@ -940,6 +994,25 @@ "\"Creative
This work is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 4.0 International License.\n", "\n" ] + }, + { + "cell_type": "markdown", + "metadata": { + "id": "-U0bCa6exLu-" + }, + "source": [ + "References\n", + "* Commons, W. (2020). File:Nucleosynthesis periodic table.svg --- Wikimedia \n", + "Commons{,} the free media repository. https://commons.wikimedia.org/w/index.php?title=File:Nucleosynthesis_periodic_table.svg&oldid=483860915 \n", + "* Fraknoi, A., Morrison, D., Wolff, S. C., OpenStax College, & Rice University. (2017). Astronomy. OpenStax, Rice University. https://openstax.org/details/books/astronomy \n", + "* Newland, J., Grzybowski, E., Hickey, J., Kuper, O., Sneden, C., & Finkelstein, K. (2020). Authentic Astronomical Research as Science Teacher Professional Development.\n", + "https://ui.adsabs.harvard.edu/abs/2020AAS...23536603N/abstract \n", + "* Sakari, C. M., Roederer, I. U., Placco, V. M., Beers, T. C., Ezzeddine, R., Frebel, A., Hansen, T., Sneden, C., Cowan, J. J., Wallerstein, G., Farrell, E. M., Venn, K. A., Matijevič, G., Wyse, R. F. G., Bland-Hawthorn, J., Chiappini, C., Freeman, K. C., Gibson, B. K., Grebel, E. K., … Watson, F. (2019). The R -Process Alliance: Discovery of a Low- α , r -process-enhanced Metal-poor Star in the Galactic Halo . The Astrophysical Journal, 874(2), 148. https://doi.org/10.3847/1538-4357/ab0c02 \n", + "* Sneden, C. (2019). Observing Run Research Parameters. UT EXES Teacher Associate Program March 2nd 2019 Conference.\n", + "Sneden, C., Cowan, J. J., & Gallino, R. (2008). Neutron-Capture Elements in the Early Galaxy. Annual Review of Astronomy and Astrophysics, 46(1), 241–288. https://doi.org/10.1146/annurev.astro.46.060407.145207 \n", + "* Soubiran, C., Le Campion, J. F., Cayrel De Strobel, G., & Caillo, A. (2010). The PASTEL catalogue of stellar parameters. Astronomy and Astrophysics, 515(11), 1–5. https://doi.org/10.1051/0004-6361/201014264 \n", + "* Stonebreaker, A. (2016). Neutron Capture Constraints. Physical Review Letters. https://physics.aps.org/assets/96e56287-2b25-482b-b075-894adc7b2b10/es66_1.png \n" + ] } ] } \ No newline at end of file