Hot Topic: Dust and biomarkers from impacts on exoplanets

by Mr Gianni Cataldi (Department of Astronomy, Stockholm University)

C61 ()


We present preliminary results from our investigation of the possibility of detecting dust generated in an impact event on an exoplanet. Dust originating from an exoplanetary surface could potentially give information on its composition, habitability or even hint to the presence of life. Indeed, certain minerals or rocks (e.g. granite) have been suggested as biomarkers. The direct detection of microbial life ejected during the impact is also considered. We aim to investigate whether any biomarkers could be detected within the debris using spectroscopic observations. We first estimate the amount of escaping mass for different impact parameters (size and density of the impactor, size of the exoplanet, etc.). We then assess the collisional evolution of the resulting circumstellar debris belt with a simplified analytical model. Although an exoplanetary atmosphere would prevent dust from escaping, dust can be produced subsequently from mutual collisions of the larger debris. The timescale for the belt to attain its brightest state as well as the overall lifetime of the belt are estimated. The fractional luminosity of the belt is calculated and compared to background noise such as exozodiacal dust.