SUMMARY OF PROPOSAL 42012
DR. JEFFREY L. LINSKY
UNIVERSITY OF COLORADO
CO USA 80309-0440
BOULDER
CAMPUS BOX 440

  E-mail: JLINSKY@JILA.COLORADO.EDU	Tel: (303) 492-7838	Fax: (303) 492-5235
  Medium: 5GB8MM

Subject: STARS                                                       
  Title: CORONAL TEMPERATURE AND CONVECTION-ZONE DEPTH: ASCA OBSERVATIONS OF CHI 1 ORI   


Abstract:
 We propose to obtain ASCA spectra of the active solar-type dwarf Chi Ori to probe
 the mechanisms which give rise to hot and cool plasma in late-type main-sequence
 coronae. These observations are part of a program to study the dependence of coronal
 temperature on convection-zone depth. Despite Einstein, ROSAT, and EUVE observations
 of Chi Ori, its true emission measure distribution, particularly above 10 MK, is
 still poorly known. SIS and GIS spectra will constrain the temperature of the very
 hottest coronal plasma. When combined with EUVE spectra, the ASCA spectra will
 further constrain the emission-measure distributions. The dependence of the
 emission-measures on convection-zone depth will allow us to test the hypothesis that increased dynamo action leads to higher coronal temperatures.

 Co-Is:
   1  MARC GAGNE          	JILA                          USA       
      MARC@CHARON.COLORADO.EDU	(303) 492-0389
   2  ALEXANDER BROWN     	CASA                          USA       


Target Name           PRI RA        Dec        Time TC  Off GIS SIS_Cts  Obs
-------------------   --- --------  --------   ---- --  --- --- -------  ---
HD 39857               0   88.5954   20.2761    30   N   Y   P  0.50000   1