Evolution of Stellar Activity and Habitable zone: I. Ultraviolet Emission of Dwarfs in Open Clusters and Field Stars

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Main Authors: Li, Xue, Wang, Song, Ma, Jun, Han, Henggeng, Huang, Yang, Liu, Jifeng
Format: Preprint
Published: 2025
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author Li, Xue
Wang, Song
Ma, Jun
Han, Henggeng
Huang, Yang
Liu, Jifeng
author_facet Li, Xue
Wang, Song
Ma, Jun
Han, Henggeng
Huang, Yang
Liu, Jifeng
contents Near-ultraviolet (NUV) radiation from dwarf stars plays a critical role in shaping the habitability of planetary systems, yet its long-term evolution across different spectral types remains poorly investigated. Based on GALEX NUV observations, we study the evolution of stellar NUV emission for a sample of 386,500 A- to M-type dwarfs spanning ages from 3 Myr to 10 Gyr, drawn from both open clusters and the field. The normalized NUV emission ($f_{\rm NUV}/f_{\rm J}$) is used to trace the evolutionary trends. Our results reveal distinct evolutionary pathways after considering the distance completeness: A and early-F dwarfs show a weak decline in NUV emission during the main-sequence phase; late-F to G dwarfs exhibit a clear decrease, consistent with continuous spin-down driven by magnetic braking; late-K and M-dwarfs undergo a rapid decline in NUV emission when they evolve from young stellar objects to main-sequence stars. Furthermore, we construct the evolutionary tracks of stellar ultraviolet habitable zone (UHZ). By comparing stellar circumstellar habitable zone (CHZ) and UHZ, we find that G- and K-type stars offer the most stable overlap between thermal and UV habitability over long-term evolution.
format Preprint
id arxiv_https___arxiv_org_abs_2509_18559
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Evolution of Stellar Activity and Habitable zone: I. Ultraviolet Emission of Dwarfs in Open Clusters and Field Stars
Li, Xue
Wang, Song
Ma, Jun
Han, Henggeng
Huang, Yang
Liu, Jifeng
Solar and Stellar Astrophysics
Astrophysics of Galaxies
Near-ultraviolet (NUV) radiation from dwarf stars plays a critical role in shaping the habitability of planetary systems, yet its long-term evolution across different spectral types remains poorly investigated. Based on GALEX NUV observations, we study the evolution of stellar NUV emission for a sample of 386,500 A- to M-type dwarfs spanning ages from 3 Myr to 10 Gyr, drawn from both open clusters and the field. The normalized NUV emission ($f_{\rm NUV}/f_{\rm J}$) is used to trace the evolutionary trends. Our results reveal distinct evolutionary pathways after considering the distance completeness: A and early-F dwarfs show a weak decline in NUV emission during the main-sequence phase; late-F to G dwarfs exhibit a clear decrease, consistent with continuous spin-down driven by magnetic braking; late-K and M-dwarfs undergo a rapid decline in NUV emission when they evolve from young stellar objects to main-sequence stars. Furthermore, we construct the evolutionary tracks of stellar ultraviolet habitable zone (UHZ). By comparing stellar circumstellar habitable zone (CHZ) and UHZ, we find that G- and K-type stars offer the most stable overlap between thermal and UV habitability over long-term evolution.
title Evolution of Stellar Activity and Habitable zone: I. Ultraviolet Emission of Dwarfs in Open Clusters and Field Stars
topic Solar and Stellar Astrophysics
Astrophysics of Galaxies
url https://arxiv.org/abs/2509.18559