Group on Active Stars & Systems

Catania Astrophysical Observatory
Dipartimento di Fisica e Astronomia dell'Universitŗ di Catania
Ricordo di Marcello RodonÚ

 La figura di Marcello RodonÚ nella ricerca Astrofisica


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Overview

Our research is focused on the physical properties of photospheres, chromospheres, transition regions (TR) and coronae of late-type stars and active binary systems. The main topics of this research are:

o1) Solar-Stellar Connection
ŁIn active binary systems (e.g. RS CVn's) and in dwarf late-type stars (e.g. dMe's) magnetic activity is of paramount interest because it shows extreme characteristics:
  • active regions covering more than half of the photospheres
  • TR and coronal emission lines close to the saturation regime
  • X-ray emission as high as some hundrenths of the stellar bolometric luminosity
Models of solar magnetic active phenomena can be validated when are able to reproduce also what is observed on magnetically active stars. On the other hand from a better knowledge of stellar activity we can improve our undestanding of the Sun behaviour.
o

2) How magnetic activity affects stellar evolution

We aim to thoroughly understand the role of magnetic activity in stellar evolution. For example, magnetic activity is responsible of stellar spin down because of magnetic braking. We use stellar magnetic active signatures to infer stellar rotation rate for slowly rotating stars.
 
o3) How magnetic activity affects detection of extrasolar planets
To detect extrasolar planets indirect methods have been developed: i)spectroscopy to detect small stellar radial velocity variations due to the stellar-planet mutual orbits and ii)photometry  to detect planet transits. Stellar magnetic activity is a huge source of noise for both the methods. Our effort is to characterize this source of noise providing tools to better detect extrasolar planets around magnetic active stars. 

The GASS logo uses as background a  sky chart centered on RS CVn (K2 IV+F5 V), the prototype of the RS CVn-type variable stars, discovered by Marcello Rodonò at the beginning of his career (Rodonò, Tesi di Laurea, 1964 - Catalano & Rodonò, 1967, Mem SAIt 38, 395).

DSS2 image from the POSSII  survey, F color


     

 


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To contact GASS: mrgrp@oact.inaf.it.
Last update: 12-10-07.