Updates and Warning!!!     Y2 (Yonsei-Yale) Isochrones

(October 20, 2004)

Version 2 isochrones are based on the new tracks with a ramping treatment for convective core overshoot when mass is near the critical mass (above which convective core develops). See Demarque et al. 2004 for details.

(May 14, 2003)

We fixed those problems discussed below (see 23 Dec. 2002 warning). The new version 2 (YYiso_v2.tar.gz) contains an improved interpolator (YYmix2.f) as well. The version 2 isochrones (file name ending with 'v2') have (1) finer age grids (41) and (2) a new overshoot scheme. All these are available from the previous page. This version will be submitted to ApJS shortly. For details about the update please read README_YYiso_v2. The interim version made on 23 Dec. 2002 will be removed soon.

(December 23, 2002)

The published interpolation routine (YYmix.f) does not function perfectly with the released isochrone sets because the isochrones do not have time steps that are fine enough. Consequently, interpolated isochrones appear to be incorrect at small (0.6-3Gyr) ages. We temporarily provide an updated set (with two newly added ages: 1.5, 2.5Gyr) with a matching interpolation routnine (mYYmix.f). Note that this new routine operates on a slightly different logic. The New version of isochrones (file name ending with 'N') are identical to the ApJ-released ones except: (1) 0.2Gyr isochrones for Z=0.00001 [A/Fe]=0.3 has been fixed. (2) 1.5 and 2.5Gyr isochrones are newly provided.  All these are available from the previous page. We are in the course of constructing additional isochrones for young ages between 0.1 and 3Gyr, and the new release will be available soon. Besides, between 1 and 3Gyr, there is discontinuity in Overshoot treatment as explained in Yi et al. (2001). We are working on a better overshoot scheme right now.


Sukyoung, Pierre, & YC