SUMMARY OF PROPOSAL 62023

DR. THEODORE SIMON
SIMON@HUBBLE.IFA.HAWAII.EDU

UNIVERSITY OF HAWAII
2680 WOODLAWN DRIVE
HONOLULU
HI USA 96822
Tel: 808-956-6317 Fax: 808-988-2790
Medium: CD ROM
Subject: STARS

DK UMA, A STAR ON THE ASCENT


ABSTRACT

The G4 III-IV yellow giant star, 24 DK UMa, is a rare example of a post-Hertzsprung Gap star, which is now poised to start its first ascent of the red giant branch. It occupies a strategic location in the H-R diagram, at the end point of a rapid spindown and decline in dynamo activity, and just prior to the onset of deep convective mixing. We propose to obtain a 40 ks ASCA spectrum, which we will analyze jointly with our existing near UV and EUV spectra to infer the distribution of chromospheric and coronal material as a function of altitude and temperature. A comparison will be made with stars of the same mass but at different phases of post main sequence evolution in order to study changes in dynamo activity.

CO-INVESTIGATORS
CO-I NAME INSTITUTE COUNTRY
STEPHEN DRAKENASA/GSFCUSA
THOMAS R. AYRESUNIV. OF COLORADOUSA

TARGETS

TARGET NAMEPRIRADECTIMETCOFFGISSIS CNTOBS
1)HD 82210
2
143.6200 69.8303 40 ksN
Y
P
0.80000
1