Commit 1104afc3 authored by Laura Ketzer's avatar Laura Ketzer
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readme changes

parent 02e90ba7
......@@ -27,7 +27,7 @@ the density of the planet,
is the efficiency of the atmospheric escape with a value between 0 and 1, and K is a factor representing the impact of Roche lobe overflow (Erkaev et al. 2007)[^Erkaev-et-al-07], which can take on values of 1 for no Roche lobe influence and <1 for planets filling significant fractions of their Roche lobes.
**Stellar high-energy evolution** <br>
Most previous studies of exoplanet evaporation approximate the stellar XUV evolution by using the average activity level of stars in a specific mass bin for well-studied clusters of different ages, and approximating it with a broken power-law with a $100$ Myr-long saturation regime. Observations and theoretical studies show, however, that stars spin down at a wider range of ages (see Barnes 2003[^Barnes-03], Matt et al. 2012[^Matt-et-al-12], Tu et al. 2015[^Tu-et-al-20], Garaffo et al. 2018[^Garaffo-et-al-2018]). In the context of exoplanet irradiation, this was explored in simulations by Tu et al. (2015)[^Tu-et-al-20] and Johnstone et al. (2015)[^Johnstone-et-al-2015]. Their studies show that the saturation timescales can range from $\sim10$ to $300 $Myr for solar-mass stars. Hence, a star that spins down quickly will follow a low-activity track, while a star that can maintain its rapid rotation will follow a high-activity track. This translates into significantly different irradiation levels for exoplanets, and thus the amount and strength of evaporation. Based on the findings by Tu et al. (2015), we generate a more realistic stellar activity evolution of the host star by adopting a simplified broken power-law model with varying saturation and spin-down time scales to approximate a low-, medium- and high-activity scenario for the host star. \vspace{0.5cm}
Most previous studies of exoplanet evaporation approximate the stellar XUV evolution by using the average activity level of stars in a specific mass bin for well-studied clusters of different ages, and approximating it with a broken power-law with a 100 Myr-long saturation regime. Observations and theoretical studies show, however, that stars spin down at a wider range of ages (see Barnes 2003[^Barnes-03], Matt et al. 2012[^Matt-et-al-12], Tu et al. 2015[^Tu-et-al-20], Garaffo et al. 2018[^Garaffo-et-al-2018]). In the context of exoplanet irradiation, this was explored in simulations by Tu et al. (2015)[^Tu-et-al-20] and Johnstone et al. (2015)[^Johnstone-et-al-2015]. Their studies show that the saturation timescales can range from ~10 to 300 Myr for solar-mass stars. Hence, a star that spins down quickly will follow a low-activity track, while a star that can maintain its rapid rotation will follow a high-activity track. This translates into significantly different irradiation levels for exoplanets, and thus the amount and strength of evaporation. Based on the findings by Tu et al. (2015), we generate a more realistic stellar activity evolution of the host star by adopting a simplified broken power-law model with varying saturation and spin-down time scales to approximate a low-, medium- and high-activity scenario for the host star. \vspace{0.5cm}
### Planet Model description: <br>
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