The Mega-MUSCLES Spectral Energy Distribution of TRAPPIST-1
Loyd, R. O. Parke; Redfield, Seth; Roberge, Aki; Brown, Alexander; France, Kevin; Youngblood, Allison; Pineda, J. Sebastian; Linsky, Jeffrey; Buccino, Andrea P.; Irwin, Jonathan; Miguel, Yamila; Kaltenegger, Lisa; Schneider, P. Christian; Froning, Cynthia S.; Duvvuri, Girish M.; Wilson, David J.; Berta-Thompson, Zachory; Kowalski, Adam; Rugheimer, Sarah; Vieytes, Mariela; Hawley, Suzanne; Tian, Feng
United States, Germany, Argentina, Netherlands, United Kingdom, China
Abstract
We present a 5 Å-100 μm spectral energy distribution (SED) of the ultracool dwarf star TRAPPIST-1, obtained as part of the Mega-MUSCLES Treasury Survey. The SED combines ultraviolet and blue-optical spectroscopy obtained with the Hubble Space Telescope, X-ray spectroscopy obtained with XMM-Newton, and models of the stellar photosphere, chromosphere, transition region, and corona. A new differential emission measure model of the unobserved extreme-ultraviolet spectrum is provided, improving on the Lyα-EUV relations often used to estimate the 100-911 Å flux from low-mass stars. We describe the observations and models used, as well as the recipe for combining them into an SED. We also provide a semiempirical, noise-free model of the stellar ultraviolet spectrum based on our observations for use in atmospheric modeling of the TRAPPIST-1 planets.