I teach statistics and study Astronomy. I'd like to create an activity for my statistics students using star data. They could enter the data into Excel and create an HR diagram. We are currently studying Correlation & Regression. I wanted to show them that a scatter-plot can be VERY interesting.

Where can I get stellar data that is already in a format that my students can use excel to create a scatter-plot? Unbeknownst to them, they will create an HR diagram.

  • $\begingroup$ Have a look at this. If you are interested I can give you the spreadsheet. This will need to be updated later this year to use the new Gaia results. iopscience.iop.org/article/10.1088/0143-0807/24/2/303 $\endgroup$ – Rob Jeffries Feb 17 '18 at 17:42
  • $\begingroup$ @RobJeffries I'm probably missing something, but isn't that for near-Sol stars only? I mean, I realize you wrote it, but the title is "The local stellar population"? $\endgroup$ – user21 Feb 18 '18 at 19:10
  • $\begingroup$ @barrycarter What's your point? Are you claiming that the local population can't be used to create an HR diagram? $\endgroup$ – Rob Jeffries Feb 18 '18 at 19:51
  • $\begingroup$ @RobJeffries Actually, rethinking it, local stars are probably better, since using a larger catalog like Tycho (or even GAIA) would bias towards brighter stars, since we can't see dimmer stars far away. My concern would be: how many "local" stars are there? The diagram might end up a bit "stringy". $\endgroup$ – user21 Feb 19 '18 at 16:20
  • $\begingroup$ @barrycarter The incomplete spreadsheet I refer to above contains 1000 stars. You can construct even more incomplete larger samples. As I understood the question, the aim was to produce something that looks interesting and non-random and that is astrophysically significant. $\endgroup$ – Rob Jeffries Feb 19 '18 at 17:23

With the Gaia Data Release 2, you can plot an HR diagram with a few million stars. From the Gaia website :

enter image description here

The data can be accessed in the search tab, where you can specify the columns you want to display (phot_bp_mean_mag and phot_rp_mean_mag). There is a button at the bottom to export the results to a file on your computer. You can then plot one of the columns as a function of the difference between the other two.

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  • $\begingroup$ I'm thinking of updating the lab experiment I mentioned in comments to the OP with the DR2 data. The trouble is, it's too good and I want them to struggle to understand the selection effects and biases. $\endgroup$ – Rob Jeffries Feb 20 at 18:54

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