The Radiation Environments of Middle-Aged F-Type Stars

By Keith Cowing
Status Report
August 9, 2023
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The Radiation Environments of Middle-Aged F-Type Stars
The full SED of Procyon A as observed from Earth. Colored regions represent the different observations or models which were combined to produce the SED, each described in detail throughout Section 3. — astro-ph.EP

Far ultraviolet (FUV) emission lines from dwarf stars are important driving sources of photochemistry in planetary atmospheres. Properly interpreting spectral features of planetary atmospheres critically depends on the emission of its host star.

While the spectral energy distributions (SEDs) of K- and M-type stars have been extensively characterized by previous observational programs, the full X-ray to infrared SED of F-type stars has not been assembled to support atmospheric modeling. On the second flight of the Suborbital Imaging Spectrograph for Transition-region Irradiance from Nearby Exoplanet host stars (SISTINE-2) rocket-borne spectrograph, we successfully captured the FUV spectrum of Procyon A (F5 IV-V) and made the first simultaneous observation of several emission features across the FUV bandpass (1010 – 1270 and 1300 – 1565 Å) of any cool star.

We combine flight data with stellar models and archival observations to develop the first SED of a mid-F star. We model the response of a modern Earth-like exoplanet’s upper atmosphere to the heightened X-ray and extreme ultraviolet radiation within the habitable zone of Procyon A. These models indicate that this planet would not experience significant atmospheric escape.

We simulate observations of the Lyα transit signal of this exoplanet with the Hubble Space Telescope (HST) and the Habitable Worlds Observatory (HWO). While marginally detectable with HST, we find that H I Lyα transits of potentially habitable exoplanets orbiting high radial velocity F-type stars could be observed with HWO for targets up to 150 pc away.

F. Cruz Aguirre, K. France, N. Nell, N. Kruczek, B. Fleming, P. C. Hinton, S. Ulrich, P. R. Behr

Comments: 22 Pages, 13 Figures, 3 Tables, to be published in ApJ
Subjects: Earth and Planetary Astrophysics (astro-ph.EP); Solar and Stellar Astrophysics (astro-ph.SR)
Cite as: arXiv:2308.04980 [astro-ph.EP] (or arXiv:2308.04980v1 [astro-ph.EP] for this version)
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Submission history
From: Fernando Cruz Aguirre
[v1] Wed, 9 Aug 2023 14:27:50 UTC (4,451 KB)

Explorers Club Fellow, ex-NASA Space Station Payload manager/space biologist, Away Teams, Journalist, Lapsed climber, Synaesthete, Na’Vi-Jedi-Freman-Buddhist-mix, ASL, Devon Island and Everest Base Camp veteran, (he/him) 🖖🏻