The Era on Non-Transiting Habitable Zone Terrestrial Planets Around M-dwarfs

Recent exoplanet surveys from the ground have discovered myriad nearby planetary systems around M- dwarfs (Teff < ~3600K), most of which are non-transiting. While transit methods have made advances in characterizing the atmospheres of planets around M-dwarfs, currently, the number of known non-transiting systems dominate by a factor of 9x within 10 pc compared to transiting ones; a large percentage of them are around M dwarfs. It is expected that the number of detected non-transiting planets around nearby M dwarfs, particularly in or near the habitable zone (HZ), will continue to grow in the coming years with more high-precision radial velocity surveys and analysis of Gaia astrometry. Characterizing these planets requires the development of alternate methods beyond primary and secondary eclipse spectroscopy or traditional direct imaging to observationally characterize their atmospheres. A clear path forward for ground-based observatories is the combination of high dispersion spectroscopy with high contrast imaging. One recently developed method for space-based observatories is the Planetary Infrared Excess, or PIE, technique. This technique targets the planetary infrared excess (as the name suggests) and its presence in the unresolved combined stellar and planetary spectra. PIE attempts to isolate the fraction of light originating from the planet by accurately modeling the stellar spectral energy distribution (SED). This presentation will discuss the growing need for characterizing the atmospheres of nearby non-transiting planets, seek community input to focus efforts on needed resources, and discuss characterization techniques including PIE.