Re: Rho Cas Activity
Posted: Sun Oct 31, 2021 5:44 pm
Hello all,
Here is my contribution to this very interesting monitoring of the Rho Cas activity.
I obtained previously a high resolution spectrum around the Halpha line of Rho Cas on July 8 at 1 h 20 TU (resolution of 17942, JJ = 2459403.5552, 6 x 600s) and recently two new spectra on October 19 at 20 h 19 TU (resolution of 19325, JJ = 2459507.3467, 7 x 600s), and on October 27 at 18 h 35 TU (resolution of 18778, JJ = 2459515.435, 6 x 600s) with my LHIRES III (grating of 2400 lines / mm).
Here is the comparison between these three spectra (the positions of the telluric lines are indicated using the PlotSpectra software) : As reported by Ernst Pollmann in the previous post, the profile of Rho Cas Halpha line has clearly evolved in recent months. This evolution is well visible between my spectra of July 8 and October 19 but I don't notice any significant change between those of October 19 and 27.
Here is a more detailed view around the Halpha line of Rho Cas : Please note that the spectra are not corrected for heliocentric radial velocity (according to the ISIS software, the values are as follows : 17.880 km/s on July 8 ; 1.408 km/s on October 19 (the movement of the Earth brings us closer to Rho Cas for these 2 dates) and -1.192 km/s on October 27 (the movement of the Earth takes us away from Rho Cas for this last date).
Zero velocity is on Halpha 6562.801 A at rest, and, according to Klochkova et al. (2014), https://arxiv.org/pdf/1312.6922v1.pdf, the systemic velocity is −47 km/s (which means here that Rho Cas and the Sun are moving towards each other) and due to low amplitude pulsations of the atmospheric layers near the photosphere, the radial velocity varies with an amplitude of about 7 km/s around this value.
Clear skies to all !!
Christophe BOUSSIN
Here is my contribution to this very interesting monitoring of the Rho Cas activity.
I obtained previously a high resolution spectrum around the Halpha line of Rho Cas on July 8 at 1 h 20 TU (resolution of 17942, JJ = 2459403.5552, 6 x 600s) and recently two new spectra on October 19 at 20 h 19 TU (resolution of 19325, JJ = 2459507.3467, 7 x 600s), and on October 27 at 18 h 35 TU (resolution of 18778, JJ = 2459515.435, 6 x 600s) with my LHIRES III (grating of 2400 lines / mm).
Here is the comparison between these three spectra (the positions of the telluric lines are indicated using the PlotSpectra software) : As reported by Ernst Pollmann in the previous post, the profile of Rho Cas Halpha line has clearly evolved in recent months. This evolution is well visible between my spectra of July 8 and October 19 but I don't notice any significant change between those of October 19 and 27.
Here is a more detailed view around the Halpha line of Rho Cas : Please note that the spectra are not corrected for heliocentric radial velocity (according to the ISIS software, the values are as follows : 17.880 km/s on July 8 ; 1.408 km/s on October 19 (the movement of the Earth brings us closer to Rho Cas for these 2 dates) and -1.192 km/s on October 27 (the movement of the Earth takes us away from Rho Cas for this last date).
Zero velocity is on Halpha 6562.801 A at rest, and, according to Klochkova et al. (2014), https://arxiv.org/pdf/1312.6922v1.pdf, the systemic velocity is −47 km/s (which means here that Rho Cas and the Sun are moving towards each other) and due to low amplitude pulsations of the atmospheric layers near the photosphere, the radial velocity varies with an amplitude of about 7 km/s around this value.
Clear skies to all !!
Christophe BOUSSIN