{"title":"Activity Cycles of Solar-Type Star HD 111395","authors":"E. S. Dmitrienko, I. S. Savanov","doi":"10.1007/s10511-025-09865-2","DOIUrl":null,"url":null,"abstract":"<p>In this study, we analyzed the behavior of the bright solar-type star HD 111395, with the aim of further comparing its photospheric, chromospheric, and coronal activity. HD 111395 is found to exhibit a higher level of activity than the Sun. The rotation periods P<sub>rot</sub> are in the range of 15.25 to 18.88 days, indicating a differential nature of surface rotation. Based on data from Sectors 23 and 49 of the TESS archive, estimates were made of the star’s spotting parameter and spot areas on its surface: 7,500 and 8,900 millionths of the solar hemisphere (MSH) for Sectors 23 and 49, respectively. These values exceed the solar mean values but are comparable to the maximum levels observed on the Sun. From Kamogata Wide-field Survey (KWS), activity cycle periods P<sub>cycl</sub> of 930 days (2.5 years), 1,830 days (5.0 years), and 3,800 days (10.4 years) were identified, while ASAS measurements yielded a period of 1,800 days (4.9 years). The obtained results are compared with activity cycles previously established based on chromospheric indicators and long-term variations in X-ray flux.</p>","PeriodicalId":479,"journal":{"name":"Astrophysics","volume":"68 2","pages":"153 - 159"},"PeriodicalIF":0.7000,"publicationDate":"2025-08-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"0","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Astrophysics","FirstCategoryId":"101","ListUrlMain":"https://link.springer.com/article/10.1007/s10511-025-09865-2","RegionNum":4,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q4","JCRName":"ASTRONOMY & ASTROPHYSICS","Score":null,"Total":0}
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Abstract
In this study, we analyzed the behavior of the bright solar-type star HD 111395, with the aim of further comparing its photospheric, chromospheric, and coronal activity. HD 111395 is found to exhibit a higher level of activity than the Sun. The rotation periods Prot are in the range of 15.25 to 18.88 days, indicating a differential nature of surface rotation. Based on data from Sectors 23 and 49 of the TESS archive, estimates were made of the star’s spotting parameter and spot areas on its surface: 7,500 and 8,900 millionths of the solar hemisphere (MSH) for Sectors 23 and 49, respectively. These values exceed the solar mean values but are comparable to the maximum levels observed on the Sun. From Kamogata Wide-field Survey (KWS), activity cycle periods Pcycl of 930 days (2.5 years), 1,830 days (5.0 years), and 3,800 days (10.4 years) were identified, while ASAS measurements yielded a period of 1,800 days (4.9 years). The obtained results are compared with activity cycles previously established based on chromospheric indicators and long-term variations in X-ray flux.
期刊介绍：
Astrophysics (Ap) is a peer-reviewed scientific journal which publishes research in theoretical and observational astrophysics. Founded by V.A.Ambartsumian in 1965 Astrophysics is one of the international astronomy journals. The journal covers space astrophysics, stellar and galactic evolution, solar physics, stellar and planetary atmospheres, interstellar matter. Additional subjects include chemical composition and internal structure of stars, quasars and pulsars, developments in modern cosmology and radiative transfer.
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