The Range of Cumulative XUV Flux on GJ 1132 b

Fuente: arXiv
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Main Authors: Barnes, Rory, Amaral, Laura N. R. do, Birky, Jessica, Davenport, James R. A., Engle, Scott, Gialluca, Megan, Shkolnik, Evgenya L.
Format: Preprint
Published: 2026
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author Barnes, Rory
Amaral, Laura N. R. do
Birky, Jessica
Davenport, James R. A.
Engle, Scott
Gialluca, Megan
Shkolnik, Evgenya L.
author_facet Barnes, Rory
Amaral, Laura N. R. do
Birky, Jessica
Davenport, James R. A.
Engle, Scott
Gialluca, Megan
Shkolnik, Evgenya L.
contents We investigate the plausible history of the XUV luminosity evolution of the planet-hosting M4 star GJ 1132 (~0.2 solar masses) to infer the cumulative incident XUV flux intercepted by the short-period (~1.6 d) Earth-sized transiting planet GJ 1132 b. We include the dominant observational uncertainties, compare two quiescent XUV luminosity evolution models, and simulate the XUV luminosity evolution from flares based on TESS data and a re-analysis of Kepler stars. We find only 4 flares in GJ 1132's TESS 123 day lightcurve, which is relatively few for M dwarfs and, in conjunction with the ~125 day period, suggests that this star is many Gyr old. We find that all model permutations predict that the planet has at least a 95% chance of receiving more than 50 times as much XUV flux as modern Earth, confirming that this planet is a good candidate for permanent atmospheric loss. We also find that an empirical XUV model for M dwarfs predicts 2-3 times more total XUV flux than a commonly used solar twin model and that the empirical model's distribution is 2-3 times narrower. Flares contribute about 20% of the cumulative XUV flux on planet b, which, while modest, ensures the planet lies firmly on the atmosphere-free side of the "cosmic shoreline."
format Preprint
id arxiv_https___arxiv_org_abs_2605_03939
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle The Range of Cumulative XUV Flux on GJ 1132 b
Barnes, Rory
Amaral, Laura N. R. do
Birky, Jessica
Davenport, James R. A.
Engle, Scott
Gialluca, Megan
Shkolnik, Evgenya L.
Earth and Planetary Astrophysics
Solar and Stellar Astrophysics
We investigate the plausible history of the XUV luminosity evolution of the planet-hosting M4 star GJ 1132 (~0.2 solar masses) to infer the cumulative incident XUV flux intercepted by the short-period (~1.6 d) Earth-sized transiting planet GJ 1132 b. We include the dominant observational uncertainties, compare two quiescent XUV luminosity evolution models, and simulate the XUV luminosity evolution from flares based on TESS data and a re-analysis of Kepler stars. We find only 4 flares in GJ 1132's TESS 123 day lightcurve, which is relatively few for M dwarfs and, in conjunction with the ~125 day period, suggests that this star is many Gyr old. We find that all model permutations predict that the planet has at least a 95% chance of receiving more than 50 times as much XUV flux as modern Earth, confirming that this planet is a good candidate for permanent atmospheric loss. We also find that an empirical XUV model for M dwarfs predicts 2-3 times more total XUV flux than a commonly used solar twin model and that the empirical model's distribution is 2-3 times narrower. Flares contribute about 20% of the cumulative XUV flux on planet b, which, while modest, ensures the planet lies firmly on the atmosphere-free side of the "cosmic shoreline."
title The Range of Cumulative XUV Flux on GJ 1132 b
topic Earth and Planetary Astrophysics
Solar and Stellar Astrophysics
url https://arxiv.org/abs/2605.03939