Journal Article

PUBDB-2024-00175

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png The energetic particle environment of a GJ 436 b-like planet

Rodgers-Lee, D. (Corresponding author)Extern* ; Rimmer, P. B. ; Vidotto, A. A. ; Louca, A. J. ; Taylor, A. M.DESY* ; Mesquita, A. L. ; Miguel, Y. ; Venot, O. ; Helling, C. ; Barth, P. ; Lacy, E.

2023
Oxford Univ. Press Oxford

This record in other databases:      

Please use a persistent id in citations: doi:10.1093/mnras/stad900

Report No.: arXiv:2303.07058

Abstract: A key first step to constrain the impact of energetic particles in exoplanet atmospheres is to detect the chemical signature of ionization due to stellar energetic particles and Galactic cosmic rays. We focus on GJ 436, a well-studied M dwarf with a warm Neptune-like exoplanet. We demonstrate how the maximum stellar energetic particle momentum can be estimated from the stellar X-ray luminosity. We model energetic particle transport through the atmosphere of a hypothetical exoplanet at orbital distances between a = 0.01 and 0.2 au from GJ 436, including GJ 436 b’s orbital distance (0.028 au). For these distances, we find that, at the top of atmosphere, stellar energetic particles ionize molecular hydrogen at a rate of ζStEP,H2 ∼ 4 × 10−10 to 2 × 10−13 s−1. In comparison, Galactic cosmic rays alone lead to ζGCR,H2 ∼ 2 × 10−20–10−18 s−1. At 10 au, we find that ionization due to Galactic cosmic rays equals that of stellar energetic particles: ζGCR,H2 = ζStEP,H2 ∼ 7 × 10−18 s−1 for the top-of-atmosphere ionization rate. At GJ 436 b’s orbital distance, the maximum ion-pair production rate due to stellar energetic particles occurs at pressure P ∼ 10−3 bar, while Galactic cosmic rays dominate for P > 102 bar. These high pressures are similar to what is expected for a post-impact early Earth atmosphere. The results presented here will be used to quantify the chemical signatures of energetic particles in warm Neptune-like atmospheres.

Note: 14 pages, 9 figures, accepted for publication in MNRAS Waiting for fulltext

---

Contributing Institute(s):

1. Theoretische Astroteilchenphysik (Z_THAT)

Research Program(s):

1. 613 - Matter and Radiation from the Universe (POF4-613) (POF4-613)

Experiment(s):

1. No specific instrument

Appears in the scientific report 2023

---

Database coverage:
; Clarivate Analytics Master Journal List ; Current Contents - Physical, Chemical and Earth Sciences ; Ebsco Academic Search ; Essential Science Indicators ; IF < 5 ; JCR ; Nationallizenz ; SCOPUS ; Science Citation Index Expanded ; Web of Science Core Collection

---

---

Linked articles:

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Preprint Rodgers-Lee, D. (Corresponding author) ; Rimmer, P. B. ; Vidotto, A. A. ; Louca, A. J. ; Taylor, A.DESY* ; Mesquita, A. L. ; Miguel, Y. ; Venot, O. ; Helling, C. ; Barth, P. ; Lacy, E.
The energetic particle environment of a GJ 436 b-like planet
[10.3204/PUBDB-2024-00490]     Files  Fulltext by arXiv.org BibTeX | EndNote: XML, Text | RIS

---