Poster Open Access

Helium observations of exoplanet atmospheres are connected to stellar coronal abundances

Poppenhaeger, Katja

Editor(s)
Wolk, Scott

Transit observations in the helium lines near 10830 Angstrom are a new successful tool to study exoplanetary atmospheres and their mass loss. Forming those lines requires ionization and recombination of helium in the exoplanetary atmosphere. This ionization is caused by stellar photons in the extreme UV (EUV); however, no currently active telescopes can observe this part of the stellar spectrum. The stellar spectrum close to the helium ionization threshold consists of individual emission lines, many of which are formed by iron at coronal temperatures. Coronal elemental abundances exhibit distinct patterns related to the first ionization potential (FIP) of those elements, with elements like iron being strongly depleted for high-activity low-mass stars. I show that stars with high versus low coronal iron abundances follow different scaling laws that tie together their X-ray emission and the EUV flux close to the helium ionization threshold. I also show that the currently observed large scatter in the relationship of EUV irradiation with exoplanetary helium transit depths can be reduced by taking coronal iron abundances into account, allowing us to target exoplanets with well-observable helium signatures with much higher confidence.

Files (613.0 kB)
Name Size
poppenhaeger_poster_landscape.pdf
md5:859c6ff8db4abbd03c5a7185fb8442ec 		247.4 kB Download
poppenhaeger_poster_landscape.png
md5:bc8616bc37fd2288adebc138c374cd36 		365.6 kB Download

  • Wood et al. (2018), The Astrophysical Journal, Volume 862, Issue 1, article id. 66, arXiv:1806.05111

  • Oklopcic and Hirata (2018), The Astrophysical Journal Letters, Volume 855, Issue 1, article id. L11, arXiv:1711.05269

  • Spake et al. (2018), Nature, Volume 557, Issue 7703, p.68-70, arXiv:1805.01298

91
112
views
downloads
All versions This version
Views 9191
Downloads 112112
Data volume 29.1 MB29.1 MB
Unique views 8585
Unique downloads 108108
More info on how stats are collected.
Indexed in
Publication date:
February 25, 2021
DOI:
10.5281/zenodo.4561985

Zenodo DOI Badge

DOI 

10.5281/zenodo.4561985

Markdown 

[![DOI](https://zenodo.org/badge/DOI/10.5281/zenodo.4561985.svg)](https://doi.org/10.5281/zenodo.4561985)

reStructedText 

.. image:: https://zenodo.org/badge/DOI/10.5281/zenodo.4561985.svg
   :target: https://doi.org/10.5281/zenodo.4561985

HTML 

<a href="https://doi.org/10.5281/zenodo.4561985"><img src="https://zenodo.org/badge/DOI/10.5281/zenodo.4561985.svg" alt="DOI"></a>

Image URL 

https://zenodo.org/badge/DOI/10.5281/zenodo.4561985.svg

Target URL 

https://doi.org/10.5281/zenodo.4561985

Keyword(s):
Cool Stars on the main sequence Exoplanet atmospheres Stellar coronae Stellar EUV emission
Meeting:
The 20.5th Cambridge Workshop on Cool Stars, Stellar Systems, and the Sun (CS20.5), virtually anywhere, March 2-4, 2021
Communities:
License (for files):
Creative Commons Attribution 4.0 International

Versions

Version 1 10.5281/zenodo.4561985 Feb 25, 2021
Cite all versions? You can cite all versions by using the DOI 10.5281/zenodo.4561984. This DOI represents all versions, and will always resolve to the latest one. Read more.

Share

Cite as

Export