Putting RGB star on the grid: update

1) Movies —> all units are cgs

Simulation 1: Full star on the grid, resolution 2563

a) ​density, variable color bar b) ​density, fixed color bar c) ​density 1D profile d) ​density 1D profile, zoomed

Simulation 2: Central part of star on the grid, resolution 643 with 3 levels of amr, so up to 2563 (zoomed in by factor 50 from above movies, so most of star is "outside" the grid)

a) ​without mesh b) ​with mesh c) ​inner region close-up, with mesh

2) Original profiles from MESA ​slides

Notes on slides:

a) Slide 4 shows the scale height as a function of radius (upper plot) and pressure v. radius (lower plot). In the lower plot, the RGB star is orange. The scale height dips significantly below the local radius below r= 2e-2 Rsun. b) Slide 5 shows the density as a function of radius. The values can be compared with what is achieved in the simulations, e.g. at the center of the star.

3) Discussion

At yesterday's meeting it was decided that resolving the center is not possible, and that the most promising approach is to introduce a sink particle at the center and then modify the pressure profile accordingly to account for the modified potential, as done in Ohlmann 2016 (PhD thesis). Serendipitously, the paper on exactly this subject came out on arXiv today: ​https://arxiv.org/pdf/1612.00008.pdf

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