Habitable Zones & Global Climate

Ultraviolet Photometry and Habitable Zones of Over 2700 Planet-Hosting Stars

By Keith Cowing

Status Report

astro-ph.SR

November 1, 2024

Filed under astro-ph.SR, astronomy, biosignature, Circumstellar Habitable Zone, GALEX, habitability, Habitable Zone, imaging, photometry, Swift, UV habitable zone, UV photometry

Ultraviolet Photometry and Habitable Zones of Over 2700 Planet-Hosting Stars — Left panel: The relation between the effective temperatures of the host stars and the effective fluxes incident on their planets. The blue, green, orange, and red dots represent gas giants, Neptunian-like planets, super-Earths, and terrestrial planets, respectively. The gray shaded area is the CHZ for each star, and the black, red, and purple lines represent the inner and outer boundaries of the CHZ for Earth mass, 5 Earth masses, and 0.1 Earth masses, respectively. Note that the three outer boundary lines overlap. The black dots represent the planets in our Solar System. Right panel: the relation between the NUV luminosities of the host stars and the distances between the stars and their planets. The pink, green, and blue shaded areas represent the UHZ for different NUV transmission rates of planetary atmospheres. The blue, green, orange, and red asterisks represent gas giants, Neptunian-like planets, super-Earths, and terrestrial planets that are located within both the CHZ and UHZ. — astro-ph.SR

The ongoing discovery of exoplanets has sparked significant interest in finding suitable worlds that could potentially support life. Stellar ultraviolet (UV; 100-3000 Å) radiation may play a crucial role in determining the habitability of their planets.

In this paper, we conducted a detailed analysis of the UV photometry of over 2700 host stars with confirmed planets, using observational data from the GALEX and Swift UVOT missions. We performed aperture photometry on single-exposure images, and provided photometric catalogs that can be used to explore a wide range of scientific questions, such as stellar UV activity and planet habitability.

By calculating the circumstellar habitable zone (CHZ) and UV habitable zone (UHZ), we found that fewer than 100 exoplanets fall within both of these zones, with the majority being gas giants. We also examined stellar activity based on their far-UV (FUV) and near-UV (NUV) emissions.

We found the FUV−NUV color more effectively represents stellar activity compared to the R′FUV and R′NUV indices. The Sun’s low FUV emission and moderate NUV emission highlight its uniqueness among (solar-like) stars.

Xue Li, Song Wang, Henggeng Han, Jifeng Liu

Comments: 22 pages, 14 figures, 6 tables. Accepted by APJS. Comments welcome!
Subjects: Solar and Stellar Astrophysics (astro-ph.SR); Earth and Planetary Astrophysics (astro-ph.EP)
Cite as: arXiv:2410.23665 [astro-ph.SR] (or arXiv:2410.23665v1 [astro-ph.SR] for this version)
https://doi.org/10.48550/arXiv.2410.23665
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Submission history
From: Xue Li [
[v1] Thu, 31 Oct 2024 06:27:52 UTC (1,319 KB)
https://arxiv.org/abs/2410.23665
Astrobiology,

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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