Volatile composition of the HD 169142 disk and its embedded planet

Fuente: arXiv
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Auteurs principaux: Keyte, Luke, Kama, Mihkel, Booth, Alice S., Law, Charles J., Leemker, Margot
Format: Preprint
Publié: 2024
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author Keyte, Luke
Kama, Mihkel
Booth, Alice S.
Law, Charles J.
Leemker, Margot
author_facet Keyte, Luke
Kama, Mihkel
Booth, Alice S.
Law, Charles J.
Leemker, Margot
contents The composition of a planet's atmosphere is intricately linked to the chemical makeup of the protoplanetary disk in which it formed. Determining the elemental abundances from key volatiles within disks is therefore essential for establishing connections between the composition of disks and planets. The disk around the Herbig Ae star HD 169142 is a compelling target for such a study due to its molecule-rich nature and the presence of a newly-forming planet between two prominent dust rings. In this work, we probe the chemistry of the HD 169142 disk at small spatial scales, drawing links between the composition of the disk and the planet-accreted gas. Using thermochemical models and archival data, we constrain the elemental abundances of volatile carbon, oxygen, and sulfur. Carbon and oxygen are only moderately depleted from the gas phase relative to their interstellar abundances, with the inner 60 au appearing enriched in volatile oxygen. The C/O ratio is approximately solar within the inner disk and rises above this in the outer disk, as expected across the H2O snowline. The gas-phase sulfur abundance is depleted by a factor of 1000, consistent with a number of other protoplanetary disks. Interestingly, the observed SiS emission near the HD 169142 b protoplanet vastly exceeds chemical model predictions, supporting previous hypotheses suggesting its origin in shocked gas or a localised outflow. We contextualise our findings in terms of the potential atmospheric composition of the embedded planet, and highlight the utility of sulfur-bearing molecules as probes of protoplanetary disk chemistry.
format Preprint
id arxiv_https___arxiv_org_abs_2410_01418
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Volatile composition of the HD 169142 disk and its embedded planet
Keyte, Luke
Kama, Mihkel
Booth, Alice S.
Law, Charles J.
Leemker, Margot
Earth and Planetary Astrophysics
Solar and Stellar Astrophysics
The composition of a planet's atmosphere is intricately linked to the chemical makeup of the protoplanetary disk in which it formed. Determining the elemental abundances from key volatiles within disks is therefore essential for establishing connections between the composition of disks and planets. The disk around the Herbig Ae star HD 169142 is a compelling target for such a study due to its molecule-rich nature and the presence of a newly-forming planet between two prominent dust rings. In this work, we probe the chemistry of the HD 169142 disk at small spatial scales, drawing links between the composition of the disk and the planet-accreted gas. Using thermochemical models and archival data, we constrain the elemental abundances of volatile carbon, oxygen, and sulfur. Carbon and oxygen are only moderately depleted from the gas phase relative to their interstellar abundances, with the inner 60 au appearing enriched in volatile oxygen. The C/O ratio is approximately solar within the inner disk and rises above this in the outer disk, as expected across the H2O snowline. The gas-phase sulfur abundance is depleted by a factor of 1000, consistent with a number of other protoplanetary disks. Interestingly, the observed SiS emission near the HD 169142 b protoplanet vastly exceeds chemical model predictions, supporting previous hypotheses suggesting its origin in shocked gas or a localised outflow. We contextualise our findings in terms of the potential atmospheric composition of the embedded planet, and highlight the utility of sulfur-bearing molecules as probes of protoplanetary disk chemistry.
title Volatile composition of the HD 169142 disk and its embedded planet
topic Earth and Planetary Astrophysics
Solar and Stellar Astrophysics
url https://arxiv.org/abs/2410.01418