The XUV-driven escape of the planets around TOI-431 & $ν^2$ Lupi

Fuente: arXiv
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Autores principales: King, George W., Corrales, Lía R., Fernández, Jorge Fernández, Wheatley, Peter J., Malsky, Isaac, Osborn, Ares, Armstrong, David
Formato: Preprint
Publicado: 2024
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author King, George W.
Corrales, Lía R.
Fernández, Jorge Fernández
Wheatley, Peter J.
Malsky, Isaac
Osborn, Ares
Armstrong, David
author_facet King, George W.
Corrales, Lía R.
Fernández, Jorge Fernández
Wheatley, Peter J.
Malsky, Isaac
Osborn, Ares
Armstrong, David
contents One of the leading mechanisms invoked to explain the existence of the radius valley is atmospheric mass loss driven by X-ray and extreme-ultraviolet irradiation, with this process stripping the primordial envelopes of young, small planets to produce the observed bimodal distribution. We present an investigation into the TOI-431 and $ν^2$ Lupi planetary systems, both of which host planets either side of the radius valley, to determine if their architectures are consistent with evolution by the XUV mechanism. With $\textit{XMM-Newton}$, we measure the current X-ray flux of each star, and see evidence for a stellar flare in the TOI-431 observations. We then simulate the evolution of all of the transiting planets across the two systems in response to the high-energy irradiation over their lifetimes. We use the measured X-ray fluxes as an anchor point for the XUV time evolution in our simulations, and employ several different models of estimating mass loss rates. While the simulations for TOI-431b encountered a problem with the initial calculated radii, we estimate a likely short ($\sim$ Myr) timespan for primordial envelope removal using reasonable assumptions for the initial planet. $ν^2$ Lupi b is likely harder to strip, but is achieved in a moderate fraction of our simulations. None of our simulations stripped any of the lower density planets of their envelope, in line with prediction. We conclude that both systems are consistent with expectations for generation of the radius valley through XUV photoevaporation.
format Preprint
id arxiv_https___arxiv_org_abs_2404_10673
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle The XUV-driven escape of the planets around TOI-431 & $ν^2$ Lupi
King, George W.
Corrales, Lía R.
Fernández, Jorge Fernández
Wheatley, Peter J.
Malsky, Isaac
Osborn, Ares
Armstrong, David
Earth and Planetary Astrophysics
Solar and Stellar Astrophysics
One of the leading mechanisms invoked to explain the existence of the radius valley is atmospheric mass loss driven by X-ray and extreme-ultraviolet irradiation, with this process stripping the primordial envelopes of young, small planets to produce the observed bimodal distribution. We present an investigation into the TOI-431 and $ν^2$ Lupi planetary systems, both of which host planets either side of the radius valley, to determine if their architectures are consistent with evolution by the XUV mechanism. With $\textit{XMM-Newton}$, we measure the current X-ray flux of each star, and see evidence for a stellar flare in the TOI-431 observations. We then simulate the evolution of all of the transiting planets across the two systems in response to the high-energy irradiation over their lifetimes. We use the measured X-ray fluxes as an anchor point for the XUV time evolution in our simulations, and employ several different models of estimating mass loss rates. While the simulations for TOI-431b encountered a problem with the initial calculated radii, we estimate a likely short ($\sim$ Myr) timespan for primordial envelope removal using reasonable assumptions for the initial planet. $ν^2$ Lupi b is likely harder to strip, but is achieved in a moderate fraction of our simulations. None of our simulations stripped any of the lower density planets of their envelope, in line with prediction. We conclude that both systems are consistent with expectations for generation of the radius valley through XUV photoevaporation.
title The XUV-driven escape of the planets around TOI-431 & $ν^2$ Lupi
topic Earth and Planetary Astrophysics
Solar and Stellar Astrophysics
url https://arxiv.org/abs/2404.10673