Importance of Small Telescopes in the Understanding of ActiveHot Stars Physics

Abstract

Active hot stars (Be stars) have been observed and studied for more thantwo decades. They exhibit hydrogen emission lines in the visibledomain and often some emission lines of singly ionized metals.These emissions originate in a circumstellar envelope produced bya strong radiative stellar wind. Since the discovery of the prototype star of this class (γ Cas) by Father A. Secchi in 1866, the basic physical properties of these objects are still poorly known. These stars are also very bright (most of them can be found in the Bright Star Catalogue) which make them good targetsfor small telescopes studies. In the following I will focus on some studies that can be done using a 40 cm telescope class. Then I willexplain how small telescopes can be combined in an interferometric network in order to reach one milliarcsecond (mas) angular resolutioneven if each telescope's aperture can be smaller thanten centimeters. With this technics it becomes possible to measurevery small and faint structures on the stellar surface of starsother than our sun.