This STAROS campaign concerns a beautiful double star, alpha Draconis.

It consists in gathering a maximum of high-resolution spectra of this double star over a period of 2 months in order to model the system with an accuracy equivalent to that of professionals if we are numerous enough to observe and frequently.

Thanks to the confrontation of the results, this observation constitutes a very good test of your quality of reduction of the spectra at high spectral resolution, in particular with regard to the spectral calibration.

The radial velocity curve thus constructed, by pooling our data, is also a very good visiting card towards the professional community for high precision radial velocity measurements for future pro-am collaborations. It is also an opportunity to exchange between us on the tricks to reach a maximum accuracy and the techniques of exploitation of the data.

Let's start to observe alpha Draconis together.

Alpha Draconis system

Credit NASA's Goddard Space Flight Center/Chris Smith (USRA) &

Spectroscopic double stars are systems whose duplicity is revealed by the observation of the periodic motion of spectral lines. This displacement of the lines is the result of the Doppler-Fizeau effect, indicating that the two stars approach or move away from us during their orbital motion around a common center of gravity. With our spectra we measure the radial velocity of the system.

Last spectrum by A. Blais