On the sensitivity of extrasolar mass-loss rate ranges: HD 209458b a case study

VILLARREAL D'ANGELO, CAROLINA S.; SCHNEITER, MATIAS; COSTA, ANDREA; VELAZQUEZ, PABLO; RAGA, ALEJANDRO; ESQUIVEL, ALEJANDRO

REVISTA MEXICANA DE ASTRONOMíA Y ASTROFíSICA

UNIV NACIONAL AUTONOMA MEXICO

Lugar: México; Año: 2014

0185-1101

We present a 3D hydrodynamic study of the effect that different stellarwind conditions and planetary wind structures have on the calculatedLyalpha absorptions during the transit of HD209458b. We approach theproblem using 3D hydrodynamic simulations. Considering a range ofstellar wind speeds ? [350-800] km s^{-1}, coronal temperature? [3-7] × 10^{6} K and two values of the polytropic indexGamma ? [1.01-1.13], while keeping fixed the stellar mass lossrate, we found a that a M_{p} range between ? [3-5] ×10^{10}g s^{-1} give account for the observational absorption inLyalpha measured for the planetary system. Also, several models withanisotropic evaporation profiles for the planetary escaping atmospherewere carried out, showing that both, the escape through polar regions,resembling the emission associated with reconnection processes, andthrough the night side, produced by a strong stellar wind thatcompresses the planetary atmosphere and inhibits its escape from the dayhemisphere yields larger absorptions than an isotropic planetary wind.