Detection of an Atmospheric Outflow from the Young Hot Saturn TOI-1268b

Fuente: arXiv
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Hauptverfasser: González, Jorge Pérez, Greklek-McKeon, Michael, Vissapragada, Shreyas, Saidel, Morgan, Knutson, Heather A., Linssen, Dion, Oklopčić, Antonija
Format: Preprint
Veröffentlicht: 2023
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author González, Jorge Pérez
Greklek-McKeon, Michael
Vissapragada, Shreyas
Saidel, Morgan
Knutson, Heather A.
Linssen, Dion
Oklopčić, Antonija
author_facet González, Jorge Pérez
Greklek-McKeon, Michael
Vissapragada, Shreyas
Saidel, Morgan
Knutson, Heather A.
Linssen, Dion
Oklopčić, Antonija
contents Photoevaporative mass-loss rates are expected to be highest when planets are young and the host star is more active, but to date there have been relatively few measurements of mass-loss rates for young gas giant exoplanets. In this study we measure the present-day atmospheric mass-loss rate of TOI-1268b, a young (110 - 380 Myr) and low density (0.71$^{+0.17}_{-0.13}$~g~cm$^{-3}$) hot Saturn located near the upper edge of the Neptune desert. We use Palomar/WIRC to search for excess absorption in the 1083~nm helium triplet during two transits of TOI-1268b. We find that it has a larger transit depth ($0.285_{-0.050}^{+0.048}\%$ excess) in the helium bandpass than in the TESS observations, and convert this excess absorption into a mass-loss rate by modeling the outflow as a Parker wind. Our results indicate that this planet is losing mass at a rate of $\log \dot{M} = 10.2 \pm 0.3$~g~s$^{-1}$ and has a thermosphere temperature of 6900$^{+1800}_{-1200}$~K. This corresponds to a predicted atmospheric lifetime much larger than 10 Gyr. Our result suggests that photoevaporation is weak in gas giant exoplanets even at early ages.
format Preprint
id arxiv_https___arxiv_org_abs_2307_09515
institution arXiv
publishDate 2023
record_format arxiv
spellingShingle Detection of an Atmospheric Outflow from the Young Hot Saturn TOI-1268b
González, Jorge Pérez
Greklek-McKeon, Michael
Vissapragada, Shreyas
Saidel, Morgan
Knutson, Heather A.
Linssen, Dion
Oklopčić, Antonija
Earth and Planetary Astrophysics
Photoevaporative mass-loss rates are expected to be highest when planets are young and the host star is more active, but to date there have been relatively few measurements of mass-loss rates for young gas giant exoplanets. In this study we measure the present-day atmospheric mass-loss rate of TOI-1268b, a young (110 - 380 Myr) and low density (0.71$^{+0.17}_{-0.13}$~g~cm$^{-3}$) hot Saturn located near the upper edge of the Neptune desert. We use Palomar/WIRC to search for excess absorption in the 1083~nm helium triplet during two transits of TOI-1268b. We find that it has a larger transit depth ($0.285_{-0.050}^{+0.048}\%$ excess) in the helium bandpass than in the TESS observations, and convert this excess absorption into a mass-loss rate by modeling the outflow as a Parker wind. Our results indicate that this planet is losing mass at a rate of $\log \dot{M} = 10.2 \pm 0.3$~g~s$^{-1}$ and has a thermosphere temperature of 6900$^{+1800}_{-1200}$~K. This corresponds to a predicted atmospheric lifetime much larger than 10 Gyr. Our result suggests that photoevaporation is weak in gas giant exoplanets even at early ages.
title Detection of an Atmospheric Outflow from the Young Hot Saturn TOI-1268b
topic Earth and Planetary Astrophysics
url https://arxiv.org/abs/2307.09515