1/15 Read Chapter 1 of Bevington
1/19 Read Chapters 2 and 3 of Bevington
1/22 Re-do 1.5, 1.7 and histogram using IDL
2/26 Use your blackbody simulator to show what a spectrum of a solar type star in the Magellanic Clouds would look like as viewed by HST across the visible band of the spectrum. Assume one night-side pass with spectral resolution of 1000 and effective area of 5000cm^2. Please print out the simulation and turn it in to me on March 2.
3/2 Download this data file a4010.txt and this IDL
4/17/04 Final Analysis Exercise
There you will find twenty new files called day0.txt through day95.txt. They contain simulated data of the absorption line from a star with a planet going around it. You have observed the planet every five days for approximately three months in exactly the same way. There is a small Doppler shift in the line that cannot be easily seen by eye, but can be pulled out through model fitting.
Each file contains two columns as before. The first column is the wavelength. The second column is the counts per bin. The first column actually contains the value dl where lam=6520.+dl. This keeps the number of digits in the wavelength column from getting out of hand.
You can model each data set as m=i*(1.-exp(-(dl-L0)*(dl-L0)/2./w/w))+b
Here, i is the intensity of the continuum. b is the detector background. L0 is the center of the line. w is the width of the line. (Hint: I used the same value of i,b and w for all the files.)
For each file, find the best fit for L0 and estimate the error bar.
Once you have your twenty wavelength shifts, convert them to velocities via the Doppler equation.
You can now fit an amplitude and period to the twenty velocities. Estimate the mass and orbital period of the planet assuming we are in the plane of the planets orbit. Assume the main star is type A0.
Write up the experiment in the format of a professional paper. Thus it should include:
I understand that you may have to make up some of this. For example, you can acknowledge financial support from your parents. You can pretend to have used the Space Telescope. You can name the star what you wish. The idea is to give this the look and feel of a real paper.
I expect the papers to be quite brief -- just a few pages. Each should include all appropriate figures and tables. At a minimum you should include a plot of one data set with a good model overplotted. You should include a table of measured doppler shifts. You should include a figure plotting the doppler shifts with your best orbital fit overlayed.
Please start this right away, as there are only two weeks left.