Stellar Characterization and a Chromospheric Activity Analysis of a K2 Sample of Planet-Hosting Stars
| Autor: | Loaiza-Tacuri, V., Cunha, Katia, Smith, Verne V., Quispe-Huaynasi, F., Costa-Almeida, Ellen, Ghezzi, Luan, Melendez, Jorge |
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| Rok vydání: | 2024 |
| Předmět: | |
| Druh dokumentu: | Working Paper |
| DOI: | 10.3847/1538-4357/ad4b15 |
| Popis: | Effective temperatures, surface gravities, and iron abundances were derived for 109 stars observed by the K2 mission using equivalent width measurements of Fe I and Fe II lines. Calculations were carried out in LTE using Kurucz model atmospheres. Stellar masses and radii were derived by combining the stellar parameters with Gaia DR3 parallaxes, V-magnitudes, and isochrones. The derived stellar and planetary radii have median internal precision of 1.8%, and 2.3%, respectively. The radius gap near $\rm R_{planet}\sim 1.9 R_\oplus$ was detected in this K2 sample. Chromospheric activity was measured from the Ca II H and K lines using the Values of $\log R^\prime_{\rm HK}$ were investigated as a function of stellar rotational period (P$_{rot}$) and we found that chromospheric activity decreases with increasing P$_{rot}$, although there is a large scatter in $\log R^\prime_{\rm HK}$ ($\sim$0.5) for a given P$_{rot}$. Activity levels in this sample reveal a paucity of F & G dwarfs with intermediate activity levels (Vaughan-Preston gap). The effect that stellar activity might have on the derivation of stellar parameters was investigated by including magnetically-sensitive Fe I lines in the analysis and we find no significant differences between parameters with and without magnetically-sensitive lines, although the more active stars ($\log R^\prime _{\rm HK}>-5.0$) exhibit a larger scatter in the differences in $T_{\rm eff}$ and [Fe/H]. Comment: 19 pages, 13 figures, 5 tables |
| Databáze: | arXiv |
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