The Mega-MUSCLES spectral energy distribution of TRAPPIST-1

Journal article

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.

Authors: Wilson, DJ; Froning, CS; Duvvuri, GM; France, K; Youngblood, A

• Publication status: Published
• Peer review status: Peer reviewed
• Publisher: IOP Publishing
• Journal: Astrophysical Journal
• Volume: 911
• Article number: 18
• Publication date: 2021-04-12
• Acceptance date: 2021-02-16
• DOI: 10.3847/1538-4357/abe771
• EISSN: 1538-4357
• ISSN: 0004-637X
• Language: English
• Keywords: ultraviolet astronomy; X-ray astronomy; spectral energy distribution; stellar atmospheres; exoplanet atmospheres; FFR; spectroscopy; exoplanet astronomy; M dwarf stars