Differences

This shows you the differences between two versions of the page.

--- tests:astropars:challenge4 [2014/10/30 13:14] – created randrae
+++ tests:astropars:challenge4 [2022/10/24 12:26] (current) – external edit 127.0.0.1
@@ Line 1: / Line 1: @@
 ====== Challenge 4: Build test data with realistic HR diagram ======
+===== Objectives =====
+  * GSP-Phot draws its training data from a synthetic HR diagram. This synthetic HR diagram currently lacks giants. In particular, it lacks significant numbers of red-clump stars, BHB stars, RR Lyraes and other important stars. Consequently, GSP-Phot cannot perform very well on such stars.
+  * Add red-clump stars, BHB stars, RR Lyraes and other important stars to the synthetic HR diagram used by GSP-Phot.
+===== Red clump =====
+  * Adopt definition of red-clump stars from [[http://adsabs.harvard.edu/abs/2014ApJ...790..127B|Bovy et al. (2014)]] ([Fe/H]>-1, 4600K<Teff<4850K, 1.8<logg<2.5 + 0.0018*(Teff - TeffRef) where TeffRef = -382.5*FeH + 4607).
+  * Selecting all available BP/RP spectra in that regime adds a significant number of red-clump stars.
+  * Caveat: The ratio of red-clump stars relative to other types of stars is not realistic (before and after this procedure).
+{{:tests:adding-red-clump-stars.png|}}
+===== Blue horizontal branch =====
+  * Adopt definition of BHB stars from [[http://adsabs.harvard.edu/abs/2004AJ....127..899S|Sirko et al. (2004)]] ([Fe/H]< -1, 7000K<Teff<13000K, 2.9<logg<4).
+  * Synthetic Gaia libraries contain no BHB stars that we could include.
+{{:tests:adding-BHB-stars.png|}}
+===== RR Lyrae =====
+  * Adopt definition of RR Lyrae stars from [[http://adsabs.harvard.edu/abs/2010A&A...519A..64K|Kolenberg et al. (2010)]] (6250K<Teff<8000K, 2.5<logg<3.8).
+{{:adding-rr-lyrae-stars.png|}}
+===== Cepheids =====
+===== Red giant branch =====