Relationship between Li abundance and chromospheric exercise indicator for energetic stars

In a research revealed in Astronomy & Astrophysics, Prof. Xing Lifeng from Yunnan Observatories of the Chinese Academy of Sciences and his collaborators discovered the chromospheric exercise index of a pattern energetic stars will increase with growing lithium abundance.

Chromospherically energetic (CA) stars are a category of energetic stars characterised by robust chromosphere, transition area and coronal exercise. Some of the objects are spectroscopically outstanding, exhibiting proof of very speedy rotation and that the Li I doublet at 670.8 nm. Whether a decent relation exists between the chromospheric exercise and the lithium abundance within the chromospheric energetic late-type stars continues to be an open query. This relation can function a foundation for the understanding of the connection amongst exercise, the sunshine parts content material and rotation of stars.

To examine the correlation between the lithium abundance and the chromospheric exercise for the chromospherically energetic late-type stars, the researchers chosen a pattern contains 14 energetic stars. These stars have been chosen from the cross-correlation of the ROSAT X-ray catalog and the Tycho catalog, and they’re robust X-ray sources which were recognized as late-type stars. Spectroscopic observations for these pattern stars have been carried out with the Coudé Echelle Spectrograph connected to the 1.8 m telescope on the Lijiang observatory of Yunnan Observatories.

Based on the high-resolution spectroscopic observations for the pattern energetic stars, the researchers calculated the lithium abundance (on a scale the place Log N(H) = 12.00) utilizing the comparability of the measured Li I λ 670.8 nm equal width with curve of development calculations in non-localthermodynamic-equilibrium circumstances. The outcomes confirmed that relationship between lithium abundance and the Ca II H & K emission index is that the exercise of pattern stars will increase with growing lithium abundance.

Moreover, the researchers discovered that the lithium abundance analogs progressively lower because the rotation intervals enhance (rotation turns into gradual) and the big values of the log R’HK associate with small values of Rossby numbers for the pattern of chromospherically energetic stars.

The study signifies that the lithium abundance of 14 chromospherically energetic stars’ analogs progressively will increase because the chromospheric exercise index will increase and/or the rotation intervals lower.