Vol 16, No 10

Chromospheric activity on the late-type star V1355 Ori using Lijiang 1.8-m and 2.4-m telescopes

Qing-Feng Pi, Li-Yun Zhang, Liang Chang, Xian-Ming Han, Hong-Peng Lu, Xi-Liang Zhang, Dai-Mei Wang


Abstract We obtained new high-resolution spectra using the Lijiang 1.8-m and 2.4-m telescopes to investigate the chromospheric activities of V1355 Ori as indicated in the behaviors of Ca II H&K, Hδ, Hγ, Hβ, Na I D 1 , D 2 , Hα and Ca II infrared triplet (IRT) lines. The observed spectra show obvious emissions above the continuum in Ca II H&K lines, absorptions in the Hδ, Hγ, Hβ and Na I D1, D2 lines, variable behavior (filled-in absorption, partial emission with a core absorption component or emission above the continuum) in the Hα line, and weak self-reversal emissions in the strong filled-in absorptions of the Ca II IRT lines. We used a spectral subtraction technique to analyze our data. The results show no excess emission in the Hδ and Hγ lines, very weak excess emissions in the Na I D1 , D2 lines, excess emission in the Hβ line, clear excess emission in the Hα line, and excess emissions in the Ca II IRT lines. The value of the ratio of EW 8542 /EW 8498 is in the range 0.9 to 1.7, which implies that chromospheric activity might have been caused by plage events. The value of the ratio E Hα /E Hβ is above 3, indicating that the Balmer lines would arise from prominence-like material. We also found time variations in light curves associated with equivalent widths of chromospheric activity lines in the Na I D1, D2, Ca II IRT and Hα lines in particular. These phenomena can be explained by plage events, which are consistent with the behavior of chromospheric activity indicators.


Keywords stars: chromosphere — stars: activity — stars: individual (V1355 Ori)

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