b Aur - Introduction

Spectrum of b Aur
The two components of b Aur have the same spectral class and almost the same luminosity (Dm=0,13 mag).
For this reason the lines belonging to both components can be easily observed.
The lines appear periodically doubled because of the Doppler effect. The maximum separation corresponds to a relative speed of the two components of 107.5+111.5 Km/sec that gives 3,27 ┼ for Mg II 4481 ┼ line. The spectrum in the picture 1 shows the situation almost at the maximum of separation of the lines.
With a program that can do peak fitting it is possible to find the line separation with a precision that can be better than 1/5 th of pixel, thus 0,15 ┼ that at this working wavelenght correspond to 9 Km/sec. Working in the red can improve the results of a factor 2.

Picture 1: A small part of the spectrum of b Aur centered on the Hg line, recorded with 0,7 ┼ resolution and 5 minutes exposure. The black stripe shows the original image on the CCD.

Go to:


[ Osservatorio Astronomico | Home page Cittadella di Scienze della Natura ]

Dal Visitatori

1996-2002© Società Astronomica G.V.Schiaparelli - l'uso di testi, immagini e dati numerici è consentito solo per consultazione e scopo personale. Per ogni altro utilizzo richiedere autorizzazione a:

SocietÓ Astronomica G.V.Schiaparelli

Ultimo aggiornamento / /2002