In an attempt to clean up my plot a bit, I've ignored my messy data points for M35 and UMMG for now. Concentrating on those clusters for which I have many data points...I've also assumed that the Pleiades (published age = 125 Myr) and the IC 2391 Supercluster (published age ~ 100 Myr) are actually the same age, and fitted a curve to the combination of data points. This is a relatively young cluster, and there doesn't seem to be a turnoff present, even for quickly evolving A-stars. There is a bit more scatter for the Castor Moving group, but with only 8 data points, I'm not surprised. Finally, the green points with no fitted line represents A stars in the Hyades cluster (triangles represent stars that are actually classified as sub-giants). This cluster is considerably older (~600 Myr) and may already have some turnoff. In fact, it looks as though the data points I have are all turn-off stars, and therfore it is not reasonable to try and fit a curve to them. As I gather data points for these clusters, I want to see how other papers calculated their stellar evolution isochrones. I could just use a code that someone else has written, but as I work mostly in Python, any code I use will probably require a bit of rewriting anyway. I'm trying to figure out what the popular code for stellar isochrones is (so far it seems like every research group uses their own code...)
Stauffer et al. 2007 has a very nice isochrone for the Pleiades (see Fig 11). Table 4 provides it in text form so you can read it in and overplot it.
ReplyDeleteThey also mention two theoretical isochrones: Siess et al. 2000 and Baraffe et al. 1998. I've used the Baraffe models a lot as they are very easy to use. A quick google search for "baraffe model" will point you to her website where you can see them as ascii tables (the one you want is probably BCAH98_iso.1).
Thanks, David...the problem with the Baraffe models is that they do not extend past Teff ~ 6500, and most of the A stars in the DEBRIS list have Teff > 7500. I'll definitely check out the other ones though!
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