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--- work:exercise0 [2021/09/16 15:04] – [Conclusions] jcsuarez
+++ work:exercise0 [2022/12/22 14:33] (current) – external edit 127.0.0.1
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+======= Exercise #0 =======
+===== Purpose =====
+The objective of **excercise-0** is to assess how far we are (the current oscillation codes) from ESTA/CoRoT exercise's conclusions. We want to set the basis on which the following exercises will be based.
+===== Procedure =====
+**<color #22b14c>Step 1</color>. The team computes the oscillations of the models**</fc>. Considering ESTA/CoRoT conclusions, for this exercise we follow the following prescriptions:
+  - Only p-modes (up to cut-off frequency) (L=0,1,2,3)
+  - With and without Richardson Extrapolation
+  - Limit (surface) conditions: ρ → 0 and P → 0
+  - Universal gravitation constant G: please, specify wether you (1) read it from the model or (2) set it in the oscillation code (and provide value)
+:!: output files names: <fc #008080>nameofthefile-CodeNameCodeVer-[No]RichRo[P].your_extension</fc>  :!::!: CodeNameVer example: <fc #008080>FILOU3_20_0 (code FILOU, version 3.20.0)</fc>
+**<color #22b14c>Step 2</color>. Analysis of the results**</fc>. I will make a first comparison of the frequencies and seismic indices, and we will discuss the results by email and/or teleconference (if needed).
+**<color #22b14c>Step 3</color>. Presentation of result & technical note**</fc>. We will write a Technical Note for the PLATO consortium, and present the results at some PW and/or WP121 meeting.
+----
+===== The models =====
+For this first exercise we will only consider five models of two different masses (1.04 and 1.5 Msun) and evolutionary stages (main sequence and sub-giant) and other two models from the BasTI grid ([[data:links|website here]]).
+^<color #800000>Download :</color> [[data:models|models wiki page]] |
+ Following ESTA/CoRoT experience, these quite different (and critical) internal structures (the presence of a convective core, and the chemical gradients present in evolved stars), would be - let's say - the worst case of study.
+^<color #4682b4>GARSTEC models</color>   ||||||||
+^Model ^Mass ^[Fe/H] ^alpha  ^ovsh  ^Nshell ^Phase ^Notes|
+|0-001 |1.04     | +0.05 | 1.6   | 0.00  |3000    | MS  | Representative of 16Cyg ~7Gyr (Travis et al. 2015)|
+|0-002 |1.04     | +0.05 | 1.6   | 0.00  |4000    | SG  | -|
+|0-003 |1.50     | +0.00 | 1.6   | 0.00  |3000    | MS  | Small convective core (around 8% of the stellar mass)|
+|0-004 |1.50     | +0.00 | 1.6   | 0.00  |4000    | TAMS| -|
+|0-005 |1.50     | +0.00 | 1.6   | 0.00  |4000    | SG  | -|
+^<color #4682b4>BaSTI models</color>   ||||||||
+|b-001 |1.00     | -0.08 | 1.6   | 0.00  |1314    | MS  | Taken directly from BaSTI online HR utility|
+|b-002 |1.00     | -0.08 | 1.6   | 0.00  |1719    | SG  | Taken directly from BaSTI online HR utility|
+----
+===== Discussion =====
+  * :!: **Note on BaSTI models**: the number of shell points is already under those proposed by ESTA/CoRoT to be suitable for oscillation computation by using Richardson extrapolation. Even with re-meshing these numbers are too low. To be checked.
+----
+===== Conclusions =====
+The main conclusion is that oscillation frequencies computed by XX,YY,ZZ, KK are similar within the range found in CoRoT/ESTA exercises (between 0.05 and 0.2 muHz) for individual frequencies and around 0.1-0.3 for large/small separations (TBV); the largest variations (up to 1-2 muHz in some cases) were due to the different boundary conditions used for the oscillation computation.
+We considered that no further investigation on such differences were necessary since the critical tests are to be done with physically-consistent models (mainly hydrostatic equilibrium, Brunt-Vaisala frequency mapping and maybe EOS proper integration with the numerical scheme).
+We concluded that we should focus on test with consistent models, starting by the standard solar model (model S by JCD).