Astrochemistry

Observations Of PAHs In The Atmospheres Of Discs And Exoplanets

By Keith Cowing

astro-ph.EP

February 16, 2022

Filed under astrochemistry

Observations Of PAHs In The Atmospheres Of Discs And Exoplanets — Employed PAH cross-sections for neutral PAHs (blue solid line) and positively charged PAHs (orange solid line). The dashed black line shows the total cross-section assuming a charge fraction of 1%. The annotated (light) gray bars show the wavelength coverage of the Twinkle, Ariel, JWST/NIRSpec and JWST/MIRI spectrographs. The dotted vertical line marks the 3.3 µm PAH feature.

Polycyclic aromatic hydrocarbons (PAHs) play a key role in the chemical and hydrodynamical evolution of the atmospheres of exoplanets and planet-forming discs.

If they can survive the planet formation process, PAHs are likely to be involved in pre-biotic chemical reactions eventually leading to more complex molecules such as amino acids and nucleotides, which form the basis for life as we know it.

However, the abundance and specific role of PAHs in these environments is largely unknown due to limitations in sensitivity and range of wavelength of current and previous space-borne facilities. Upcoming infrared space spectroscopy missions, such as Twinkle and Ariel, present a unique opportunity to detect PAHs in the atmospheres of exoplanets and planet-forming discs. In this work we present synthetic observations based on conservative numerical modeling of typical planet-forming discs and a transiting hot Saturnian planet around solar type star.

Our models show that Twinkle and Ariel might both be able to detect the 3.3 micron PAH feature within reasonable observing time in discs and transiting planets, assuming that PAHs are present with an abundance of at least one tenth of the interstellar medium value.

Barbara Ercolano (USM, LMU), Christian Rab (USM, LMU, MPE), Karan Molaverdikhani (USM, LMU), Billy Edwards (Blue Skies SPace, UCL)Thomas Preibisch (USM, LMU), Leonardo Testi (ESO), Inga Kamp (Kapteyn), Wing-Fai Thi (MPE)

Comments: 11 pages, 9 figures, accepted for publication in MNRAS
Subjects: Earth and Planetary Astrophysics (astro-ph.EP)
Cite as: arXiv:2202.08252 [astro-ph.EP] (or arXiv:2202.08252v1 [astro-ph.EP] for this version)
Submission history
From: Barbara Ercolano Prof
[v1] Wed, 16 Feb 2022 18:54:50 UTC (2,726 KB)
https://arxiv.org/abs/2202.08252
Astrobiology, Astrochemistry

Keith Cowing

Explorers Club Fellow, ex-NASA Space Station Payload manager/space biologist, Away Teams, Journalist, Lapsed climber, Synaesthete, Na’Vi-Jedi-Freman-Buddhist-mix, ASL, Devon Island and Everest Base Camp veteran, (he/him) 🖖🏻

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