tokens: 8 . It can be seen from Fig. 8 that the age of red giants estimated by our model is usually younger than the age given by Pinsonneault et al. ( 2018 ). This is determined by the sample (Sanders Das 2018 ; Yu et al. 2018 ) we used to train the red giant age model. Pinsonneault et al. ( 2018 ) used the revised scaling relation when inferring stellar mass from seismic data, and they took the influence of the [ α /Fe] into account when estimating the age of red giants. Wu et al. ( 2018 ) also mentioned these two points when comparing the red giant ages of Sanders Das ( 2018 ). It should be mentioned that, in principle, using asteroseismology to estimate the age of red giants should be much more precise. In this work, we used the stellar age given by Sanders Das ( 2018 ) as a standard, established different stellar age models by using different stellar parameters, and compared the model results. By comparison, we infer which parameters are used to establish the stellar age model that is more accurate, that is, to filter out which stellar parameters are more relevant to the stellar age. Figure 8. The age of the red giant estimated using our model is compared with the age given by Pinsonneault et al. ( 2018 ). 4.2 EW of the magnetic activity lines and the age of red giants In Table 3 , by comparing the input parameter combinations ‘b’ and ‘j’, ‘d’ and ‘f’, ‘g’, ‘h’, ‘i’, we know that no matter adding all or part of the EW of the magnetic activity lines to the input parameters, the red giants age estimation cannot be improved. This suggest that in the red giants, the EW of the magnetic activity lines has no direct correlation with the age of the red giants. When studying the relationship between stellar chromospheric activity and age in the open clusters, Zhang et al. ( 2019 ) found that the chromospheric activity indices (log and log ) of low-mass stars with strong surface magnetic field are strongly correlated with the stellar age, while for those stars with relatively large mass and weak surface magnetic field, their stellar chromospheric activity indices are weakly correlated with the age. In other words, the relationships between stellar age and chromosphere activity indices are affected by the intensity of the stellar surface magnetic field. Red giants are formed when low- or intermediate-mass stars have finished burning the hydrogen in their cores. Stello et al. ( 2016 ) mentioned that in the red giants with asteroseismic signals, the outer layer dynamo has shut off at the end of core-hydrogen-burning, and most of these red giants have core-dynamo-generated fields. In Section 2 , by analysing the EW of the magnetic activity lines, we know that there is no strong magnetic activity in the chromosphere and photosphere of all red giants in this study sample. This is consistent with the conclusion of Stello et al. ( 2016 ). Moreover, the results of Chaplin et al. ( 2000 ) showed that the amplitude of the solar p mode decreases with the increase of
ner_tags: O O O O O O O O O O O O O O O O O O O O O O O O O O O B-Citation I-Citation I-Citation I-Citation I-Citation I-Citation O O O O O O B-Citation I-Citation I-Citation O B-Citation I-Citation I-Citation I-Citation O O O O O O O O O O B-Citation I-Citation I-Citation I-Citation I-Citation I-Citation O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B-Citation I-Citation I-Citation I-Citation I-Citation I-Citation O O O O O O O O O O O O B-Citation I-Citation I-Citation I-Citation I-Citation O O O O O O O O B-ObservationalTechniques O O O O O O O O O O O O O O O O O O O O O O B-Citation I-Citation I-Citation I-Citation I-Citation O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B-Citation I-Citation I-Citation I-Citation I-Citation I-Citation O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B-Citation I-Citation I-Citation I-Citation I-Citation I-Citation O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B-Citation I-Citation I-Citation I-Citation I-Citation I-Citation O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O O B-Citation I-Citation I-Citation I-Citation I-Citation I-Citation O O O O B-Citation I-Citation I-Citation I-Citation I-Citation I-Citation O O O O O O B-CelestialObject O O O O O O O