| Name: | Gopal Hazra |
| Affiliation: | IIT Kanpur |
| Conference ID : | ASI2024_559 |
| Title : | Estimating Hydrodynamic Escape of H2-H2O atmospheres from Terrestrial Exoplanets Orbiting M-dwarfs |
| Authors : | Gopal Hazra
Manuel Güdel
Gwenaël Van Looveren |
| Authors Affiliation: | Gopal Hazra (IIT Kanpur, Kanpur-208016, India)
Manuel Güdel (Dept of Astrophysics, University of Vienna, Vienna, Austria)
Gwenaël Van Looveren (Dept of Astrophysics, University of Vienna, Vienna, Austria) |
| Mode of Presentation: | Oral |
| Abstract Category : | Sun, Solar System, Exoplanets, and Astrobiology |
| Abstract : | M-dwarfs are very active and have intense X-ray and Ultraviolet (XUV) radiation, so it is very difficult to find habitable planets around M-dwarfs. Our aim is to elucidate this matter and understand whether the planetary atmosphere can survive around M-dwarfs using planetary escape code Kompot that includes a complicated chemical network and self-consistently computes atmospheric escape of each species in the atmosphere due to intense stellar XUV radiation. The young terrestrial planets orbiting M-dwarf stars mostly consist of an H2 atmosphere or H2O atmosphere but planet formation theories suggest that the atmosphere is a mix of H2 and H2O. Although there are some studies of H2 and H2O escape individually, the atmospheric escape for the mixed atmosphere is not many. Here using the Kompot code, we studied the atmospheric escape for the H2 − H2O dominated atmosphere. We computed the mass-loss rate from an Earth-like planet orbiting the M-Dwarf Trappist-1 at a distance of 0.02 AU. The hydrogen and water ratios are taken as 90% and 10%. We found a resulting mass-loss rate of 4.4 x 10^8 g/s for the H2-H2O atmosphere. The exobase temperature for the planet is 2401 K which is reasonable for a terrestrial exoplanet. In all of our escape calculations, we have only considered the radiative cooling for the water molecule due to rotational bands. However, the emission due to the vibrational band also plays an important role, especially in our case where the temperature of the outflowing atmosphere is significantly high. As an ongoing effort, we have included the contribution of the vibrational band of water molecules in radiative cooling and investigated its role, as it would be important for cooling down the atmosphere leading to a less efficient mass loss and a possibility of survival of planetary atmosphere orbiting M-dwarfs. |
