Determination Size/Physical Properties of Active Regions inRS CVn Sys Rotational Modulation/Doppler Imaging
Abstract
The primary objective of this proposal is to determine the geometric size and physical properties of active regions in two properly chosen bright RS CVn systems.. Previous observing campaigns by this group, and especially our observations of II Peg in October 1981, have indicated that RS CVn systems with simple, nearly sinusoidal photometric waves of large amplitude have one dominant active region and large amplitude variations in the transition region and chromospheric ultraviolet emission lines as the active region rotates on to and off of the visible hemisphere. We propose to determine the size of this active region by rotational modulation of the line fluxes obtained at least 12 times over a period. We will confirm the existence of this active region by observing the Doppler shift of the emission lines when the active region -is near both limbs, a technique called Doppler imaging. Once the size, latitude, and longitude of the active region are determined, we can determine the emission line surface fluxes for the active region alone from the line flux enhancements. We can then compute models of the active region and quiet components separately using emission measure techniques or by matching computed and observed surface fluxes in lines of Mg II, Si II-IV, C II-IV, and N V and by comparison with density-sensitive line ratios. As before, we will set up a major coordinated observing campaign to obtain radio observations (VLA), optical photometry, and optical spectroscopy.
- Publication:
-
IUE Proposal
- Pub Date:
- July 1984
- Bibcode:
- 1984iue..prop.1848L