Dorn, Caroline; Heng, Kevin (2018). Secondary Atmospheres on HD 219134 b and c. Astrophysical journal, 853(1), p. 64. Institute of Physics Publishing IOP 10.3847/1538-4357/aa9c80
|
Text
Dorn_2018_ApJ_853_64.pdf - Published Version Available under License Publisher holds Copyright. Download (2MB) | Preview |
We analyze the interiors of HD~219134~b and c, which are among the coolest super Earths detected thus far. Without using spectroscopic measurements, we aim at constraining if the possible atmospheres are hydrogen-rich or hydrogen-poor. In a first step, we employ a full probabilistic Bayesian inference analysis in order to rigorously quantify the degeneracy of interior parameters given the data of mass, radius, refractory element abundances, semi-major axes, and stellar irradiation. We obtain constraints on structure and composition for core, mantle, ice layer, and atmosphere. In a second step, we aim to draw conclusions on the nature of possible atmospheres by considering atmospheric escape. Specifically, we compare the actual possible atmospheres to a threshold thickness above which a primordial (H2-dominated) atmosphere can be retained against evaporation over the planet's lifetime. The best constrained parameters are the individual layer thicknesses. The maximum radius fraction of possible atmospheres are 0.18 and 0.13 R (radius), for planets b and c, respectively. These values are significantly smaller than the threshold thicknesses of primordial atmospheres: 0.28 and 0.19 R, respectively. Thus, the possible atmospheres of planets b and c are unlikely to be H2-dominated. However, whether possible volatile layers are made of gas or liquid/solid water cannot be uniquely determined. Our main conclusions are: (1) the possible atmospheres for planets b and c are enriched and thus possibly secondary in nature, and (2) both planets may contain a gas layer, whereas the layer of HD 219134 b must be larger. HD 219134 c can be rocky.
Item Type: |
Journal Article (Original Article) |
|---|---|
Division/Institute: |
08 Faculty of Science > Physics Institute > Space Research and Planetary Sciences 08 Faculty of Science > Physics Institute 10 Strategic Research Centers > Center for Space and Habitability (CSH) 08 Faculty of Science > Physics Institute > NCCR PlanetS |
UniBE Contributor: |
Dorn, Caroline, Heng, Kevin |
Subjects: |
500 Science 500 Science > 520 Astronomy 500 Science > 530 Physics 600 Technology > 620 Engineering |
ISSN: |
0004-637X |
Publisher: |
Institute of Physics Publishing IOP |
Language: |
English |
Submitter: |
Janine Jungo |
Date Deposited: |
28 Mar 2018 10:54 |
Last Modified: |
05 Dec 2022 15:11 |
Publisher DOI: |
10.3847/1538-4357/aa9c80 |
BORIS DOI: |
10.7892/boris.112374 |
URI: |
https://boris.unibe.ch/id/eprint/112374 |
Actions (login required)
 |
Edit item |