The Mega-MUSCLES Spectral Energy Distribution Of TRAPPIST-1

22 Feb 2021  ·  David J. Wilson, Cynthia S. Froning, Girish M. Duvvuri, Kevin France, Allison Youngblood, P. Christian Schneider, Zachory Berta-Thompson, Alexander Brown, Andrea P. Buccino, Suzanne Hawley, Jonathan Irwin, Lisa Kaltenegger, Adam Kowalski, Jeffrey Linsky, R. O. Parke Loyd, Yamila Miguel, J. Sebastian Pineda, Seth Redfield, Aki Roberge, Sarah Rugheimer, Feng Tian, Mariela Vieytes ·

We present a 5A-100um 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 Lyman alpha to EUV relations often used to estimate the 100-911A 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 semi-empirical, noise-free model of the stellar ultraviolet spectrum based on our observations for use in atmospheric modelling of the TRAPPIST-1 planets. read more

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