Search for Hot Plasmas in the Outer Atmospheres of K Giants - Repeat of GTO1177 for HOPR#132 and 144
Abstract
We will measure the amount of plasma hotter than 10,000 K (or establish small upper limits) in the outer atmospheres of K giant stars thought to have little hot material. A second goal is to derive models of the hot plasma in the transition regions of early K giants with very low heating rates due to slow rotation and very weak magnetic field generation. We will measure emission lines of C III, Si III, C IV, Si IV, and N V in deep specta. Upper limits to the strength of these emission lines will place stringent constraints on possible nonradiative heating processes. Observations of weak intersystem lines will provide estimates of the electron density needed for atmospheric modeling. We will attempt to determine whether the hot plasma (and the required heating) are global or isolated to small regions on the star due to magnetic fields or stochastic heating processes. Echelle resolution Mg II and O I emission profiles will be used for stellar wind modeling. G140L exposures are returned to the proposal to detect weak high temperature lines. THIS IS AN AMMENDED VERSION OF GTO 1177 WHICH FAILED IN CYCLE 2.
- Publication:
-
HST Proposal
- Pub Date:
- January 1994
- Bibcode:
- 1994hst..prop.5647L