Wind-AE: a fast, open-source 1D photoevaporation code with metal and multifrequency X-ray capabilities
File(s)
Published version
Author(s)
Broome, Madelyn I
Murray-Clay, Ruth
Mccann, John R
Owen, James E
Type
Journal Article
Abstract
Throughout their lives, short-period exoplanets (<100 days) experience X-ray and extreme-UV (XUV) stellar irradiation that can heat and photoionize planets’ upper atmospheres, driving transonic outflows. This photoevaporative mass loss plays a role in both evolution and observed demographics; however, mass-loss rates are not currently directly observable and can only be inferred from models. To that end, we present an open-source fast 1D, XUV multifrequency, multispecies, steady-state, hydrodynamic Parker wind photoevaporation relaxation model based on Murray-Clay et al. The model can move smoothly between high and low flux regimes and accepts custom multifrequency stellar spectra. While the inclusion of high-energy X-rays increases mass-loss rates (M), metals decrease M, and the net result for a typical hot Jupiter is a similar M but a hotter, faster, and more gradually ionized wind. We find that mulitfrequency photons (e.g., 13.6–2000 eV) are absorbed over a broader range of heights in the atmosphere, resulting in a wind launch radius, RXUV, that is of order 10 nanobars for all but the highest surface gravity planets. Grids of H/He solar-metallicity atmospheres reveal that, for typical hot Jupiters like HD 209458b, RXUV ≈ 1.1RP–1.8RP for low fluxes, meaning that the energy-limited mass-loss rate,MElim(R), computed at R = RP is a good approximation. However, for planets with low escape velocities, like many sub-Neptunes and super-Earths, RXUV can be ≫RP, making it necessary to use MElim(R=RXUV) to avoid significantly underestimating mass-loss rates. For both high escape velocities and large incident fluxes, radiative cooling is significant and energy-limited mass loss overestimates M.
Date Issued
2025-12-20
Date Acceptance
2025-10-16
Citation
The Astrophysical Journal (ApJ), 2025, 995 (2)
ISSN
0004-637X
Publisher
IOP Publishing
Journal / Book Title
The Astrophysical Journal (ApJ)
Volume
995
Issue
2
Copyright Statement
© 2025. The Author(s). Published by the American Astronomical Society. Original content from this work may be used under the terms of the Creative Commons Attribution 4.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI.
License URL
Identifier
10.3847/1538-4357/ae14f4
Subjects
Astronomy & Astrophysics
ATMOSPHERIC ESCAPE
ATOMIC DATABASE
GASEOUS PLANETS
GIANT PLANETS
GREY ANALYTICAL-MODEL
H-ALPHA
HYDRODYNAMIC ESCAPE
Physical Sciences
POWERED MASS-LOSS
Science & Technology
SUPER-EARTHS
TRANSMISSION SPECTRUM
Publication Status
Published
Article Number
198
Date Publish Online
2025-12-16