Habitable Zones and M dwarf Activity across Time ("HAZMAT")

The HAbitable Zones and M dwarf Activity across Time (HAZMAT) program assesses the lifetime exposure of planets to stellar ultraviolet (UV) radiation using GALEX data, HST COS and STIS spectra, and semi-empirical, full-wavelength models. The program quantifies the evolution of far- and near-UV (FUV; NUV) emission for early- and mid-M (HAZMAT I), late-M (HAZMAT III), and K (HAZMAT V) type stars, as well as extreme-UV (EUV) emission from early-M stars (HAZMAT VI). The data products below are high-resolution synthetic spectra (EUV – IR; 100 Angstroms to 5.5 microns) of early-M stars at five distinct ages between 10 Myr and 5 Gyr. The spectra are computed with the PHOENIX atmosphere code from one-dimensional upper atmosphere models of 0.35 and 0.45 solar mass stars (stellar parameters given in Table 1 of the HAZMAT VI paper). The wavelengths (given in Angstroms) are in vacuum and the wavelength grid has a resolution of <0.1 Angstroms. The flux densities (given in ergs/cm^2/s/Angstrom) are that at the stellar surface and are scalable to a distance D via (R_star/D)^2 where R_star is dependent on the age and mass of the star from Table 1. Downloadable data products include five spectra per 0.35 and 0.45 solar mass stars at ages of 10, 45, 120, 650, and 5000 Myr. The spectra reproduce either the minimum ("MIN"), lower quartile ("LQ"), median ("MED"), upper quartile ("UQ"), or maximum ("MAX") FUV and NUV flux density per age as calculated from the GALEX stellar sample in HAZMAT I. Also available for download are high-resolution full-wavelength (100 Angstrom – 950 micron) PHOENIX spectra of specific M dwarf planet host stars from Peacock et al. 2019a,b. The data products are synthetic spectra in wavelength (Angstrom) and flux density at the surface of the star (ergs/s/cm^2/ Angstrom). In the publications, the flux densities are scaled by (R_star/D)^2. The stars are TRAPPIST-1, GJ 176, GJ 436, and GJ 832.