by Malin Moll
Line identification and bisector analysis
The first year of our project is over and a total of 70 spectra have been used for temperature and RV measurements. In order to get a better overview of the processes in the star, we now try to identify all well defined lines in our spectral range (6330-6600A) using synthetic spectra.
We also want to study the winds in the atmospheric layers. For this purpose we are currently testing the bisector analysis at FeI 6412 as follows:
The areas 20%-30% (bottom) and 60%-70% (top) are selected. 100% means 1- (the flux value at the line minimum).
The bisector velocity span results from (top)-(bottom).
We also measure the width at 20%, 50% and 70% with the script. The idea behind it is that we can see the evolution of the winds through the layers.
The blue areas show the BVS and the red areas the measuring range for the width.
We chose the FeI 6412 line because it was also chosen by the professionals as the RV line, because unlike most other lines it is not disturbed by blends or emissions.
Results of the measurements will follow.
There is also a new paper on the eruption of rho Cas in 2013: https://arxiv.org/abs/1812.03065