Update 4/27

Charge Exchange

Here's the split of absorption between hot and cold neutrals:

https://www.pas.rochester.edu/~adebrech/ChargeExchange/HD209458b_charge_exchange_split_test.png

Shows pretty much what the theoretical calculation does - the hot neutral density just isn't high enough to get significant absorption. You can see a lot more broadening in the hot case, the total absorption is just very low compared to the cold.

Papers

Study Fluids Planet Resolution Stellar wind density (/cm3) Stellar wind velocity (cm/s) Stellar wind temperature (K) Stellar Wind Mass Loss (g/s) Results
Ours Single (4 species tracers) HD 209458b, self-consistent 3D, ~0.01 Rp 7x102, 4x104 1.3x107 8x105 1.6x109, 8.2x1010 A few percent absorption
Khodachenko et al 2019 Multifluid (H2, H2+, H3+, HeI+II, HI+II, e-) GJ 436b, self-consistent 3D, ~0.5 Rp in tail 1.2-8x103 4x107 6x105 7.5x1010-5x1011 ~50% blue absorption from parameter set #11 of table 2
Khodachenko et al 2017 Multifluid (H2, H2+, H3+, HeI+II, HI+II (stellar and planetary), e-) HD 209458b, self-consistent 2D, ? 5x103-3x104 2-5x107 1-3x106 Fig 9 - absorption of a few percent by hot neutrals
Shaikhislamov et al 2016 Multifluid (H2, H2+, H3+, HI+II (stellar and planetary), e-) HD 209458b, self-consistent 2D, 1.3x102-3.4x103 2.3-6.6x107 0.9-2.9x106 Hot neutrals ~10x lower than required to create observed absorption (max column density ~1011 at -100 km/s)
Bourrier et al 2016 Particle model GJ 436b (4 Rp) 3D 1.3,3.3x103 (Best-fit values) 8.5x106 (Best-fit) 1.2x104 (Best-fit) Good fit to observations
Christie et al 2016 Single-fluid HD 209458b (Rp) 2D, cyl, ~0.05 Rp 104 2x107 106 Absorption of a few percent
Tremblin & Chiang 2013 Single-fluid? HD 209458b (4 Rp) 2D, 0.00625 Rp 2.9x104 1.3x107 106 1012 Absorption of ~10%

Summary: After reviewing all of the papers, it's starting to look like everyone can fit GJ 436 but not HD 209458.

(Not sure why only the first attachment link is working…. Open post to download attachments.)

Spring code

Basically done. A few more problems to update, some minor refactoring and upgrades for the spring part (particularly, need to figure out the correct places to parallelize with OpenMP).

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