Stellar Parameters and Spectroscopic Properties of TESS Objects Observed in the LAMOST Low- and Medium-resolution Spectral Survey
Stellar parameters and magnetic activity are important for the understanding of stellar physics and dynamo theory. We have used LAMOST spectroscopic surveys to study stellar parameters and magnetic activity properties of TESS objects. There are 46,684 spectra of 31,385 TESS objects in the LAMOST low...
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IOP Publishing
2022-01-01
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| Series: | The Astrophysical Journal Supplement Series |
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| Online Access: | https://doi.org/10.3847/1538-4365/ac9b28 |
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| author | Li-yun Zhang Tianhao Su Prabhakar Misra Xianming L. Han Gang Meng Qingfeng Pi Jiawei Yang |
| author_facet | Li-yun Zhang Tianhao Su Prabhakar Misra Xianming L. Han Gang Meng Qingfeng Pi Jiawei Yang |
| author_sort | Li-yun Zhang |
| collection | DOAJ |
| description | Stellar parameters and magnetic activity are important for the understanding of stellar physics and dynamo theory. We have used LAMOST spectroscopic surveys to study stellar parameters and magnetic activity properties of TESS objects. There are 46,684 spectra of 31,385 TESS objects in the LAMOST low-resolution spectral survey. We have calculated equivalent widths of Ca ii H and K, and H α lines, and discussed the relationship of chromospheric activity with stellar temperature. There are 25,710 spectra of 10,404 stars with repeated low-resolution observations. We found that there are 694 objects with variations of the H α line and 1406 objects with varying radial velocities. Moreover, there are 14,099 spectra of 5834 TESS objects in the LAMOST medium-resolution survey, of which there are 2666 objects with H α variations and 1480 objects with variation in radial velocities. By using the light curves of the TESS objects in the LAMOST field, we detected 4269 flare events and determined their flare parameters. We have confirmed that the fraction of the flare stars increases as stellar temperature decreases. There is also an observed relationship between the flare energy and chromospheric activity. We have calculated the power-law index between the flare energy and decay time using TESS data to be 0.27(0.01), which can be explained by the magnetic reconnection theory. We confirmed that ${R}_{{\rm{H}}\alpha }^{{\prime} }$ is stable for Rossby number R < 0.1 and decreases with the increase of Rossby number R > 0.1. There is a positive correlation between the brightness variation amplitude due to star spots from TESS and the H α intensity from LAMOST. |
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| language | English |
| last_indexed | 2024-03-12T03:17:21Z |
| publishDate | 2022-01-01 |
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| series | The Astrophysical Journal Supplement Series |
| spelling | doaj.art-bdda280ddd164aaea765d3a33c99cebd2023-09-03T14:08:28ZengIOP PublishingThe Astrophysical Journal Supplement Series0067-00492022-01-0126411710.3847/1538-4365/ac9b28Stellar Parameters and Spectroscopic Properties of TESS Objects Observed in the LAMOST Low- and Medium-resolution Spectral SurveyLi-yun Zhang0https://orcid.org/0000-0002-2394-9521Tianhao Su1Prabhakar Misra2https://orcid.org/0000-0001-6843-7135Xianming L. Han3https://orcid.org/0000-0001-7638-0351Gang Meng4Qingfeng Pi5Jiawei Yang6College of Physics, Guizhou University , Guiyang 550025, People's Republic of China ; liy_zhang@hotmail.com; Key Laboratory for the Structure and Evolution of Celestial Objects, Chinese Academy of Sciences , Kunming 650011, People's Republic of ChinaCollege of Physics, Guizhou University , Guiyang 550025, People's Republic of China ; liy_zhang@hotmail.comDepartment of Physics & Astronomy, Howard University , Washington, DC 20059, USACollege of Physics, Guizhou University , Guiyang 550025, People's Republic of China ; liy_zhang@hotmail.com; Department of Physics and Astronomy and SARA, Butler University , Indianapolis, IN 46208, USACollege of Physics, Guizhou University , Guiyang 550025, People's Republic of China ; liy_zhang@hotmail.comSchool of Pharmacy, Guizhou University of Traditional Chinese Medicine , Guiyang 550025, People's Republic of ChinaKechuang Industrial Development Company Limited and Gui’an Supercomputing Center , Gui’an New Area. Guiyang, People's Republic of ChinaStellar parameters and magnetic activity are important for the understanding of stellar physics and dynamo theory. We have used LAMOST spectroscopic surveys to study stellar parameters and magnetic activity properties of TESS objects. There are 46,684 spectra of 31,385 TESS objects in the LAMOST low-resolution spectral survey. We have calculated equivalent widths of Ca ii H and K, and H α lines, and discussed the relationship of chromospheric activity with stellar temperature. There are 25,710 spectra of 10,404 stars with repeated low-resolution observations. We found that there are 694 objects with variations of the H α line and 1406 objects with varying radial velocities. Moreover, there are 14,099 spectra of 5834 TESS objects in the LAMOST medium-resolution survey, of which there are 2666 objects with H α variations and 1480 objects with variation in radial velocities. By using the light curves of the TESS objects in the LAMOST field, we detected 4269 flare events and determined their flare parameters. We have confirmed that the fraction of the flare stars increases as stellar temperature decreases. There is also an observed relationship between the flare energy and chromospheric activity. We have calculated the power-law index between the flare energy and decay time using TESS data to be 0.27(0.01), which can be explained by the magnetic reconnection theory. We confirmed that ${R}_{{\rm{H}}\alpha }^{{\prime} }$ is stable for Rossby number R < 0.1 and decreases with the increase of Rossby number R > 0.1. There is a positive correlation between the brightness variation amplitude due to star spots from TESS and the H α intensity from LAMOST.https://doi.org/10.3847/1538-4365/ac9b28Stellar activityStellar chromospheresStellar flares |
| spellingShingle | Li-yun Zhang Tianhao Su Prabhakar Misra Xianming L. Han Gang Meng Qingfeng Pi Jiawei Yang Stellar Parameters and Spectroscopic Properties of TESS Objects Observed in the LAMOST Low- and Medium-resolution Spectral Survey The Astrophysical Journal Supplement Series Stellar activity Stellar chromospheres Stellar flares |
| title | Stellar Parameters and Spectroscopic Properties of TESS Objects Observed in the LAMOST Low- and Medium-resolution Spectral Survey |
| title_full | Stellar Parameters and Spectroscopic Properties of TESS Objects Observed in the LAMOST Low- and Medium-resolution Spectral Survey |
| title_fullStr | Stellar Parameters and Spectroscopic Properties of TESS Objects Observed in the LAMOST Low- and Medium-resolution Spectral Survey |
| title_full_unstemmed | Stellar Parameters and Spectroscopic Properties of TESS Objects Observed in the LAMOST Low- and Medium-resolution Spectral Survey |
| title_short | Stellar Parameters and Spectroscopic Properties of TESS Objects Observed in the LAMOST Low- and Medium-resolution Spectral Survey |
| title_sort | stellar parameters and spectroscopic properties of tess objects observed in the lamost low and medium resolution spectral survey |
| topic | Stellar activity Stellar chromospheres Stellar flares |
| url | https://doi.org/10.3847/1538-4365/ac9b28 |
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