SUMMARY OF PROPOSAL 51021

DR. SHUNJI KITAMOTO
KITAMOTO@ESS.SCI.OSAKA-U.AC.JP

OSAKA UNIVERSITY, GRADUATE SCHOOL OF SCIENCE
OSAKA JAPAN 560
TOYONAKA
1-1, MACHIKANEYAMA
Tel: 06-850-5478 Fax: 06-850-5539
Medium: 2.5GB8MM
Subject: STARS

OBSERVATIONAL STUDY OF "COSMIC ABUNDANCE"


ABSTRACT

The metal abundance of stars and SNRs derived from ASCA observation is generally smaller than the so-called "cosmic abundance". We are trying to study this mysterious problem. On early type stars, a simple analysis of ASCA data, assuming a thin thermal plasma model, leads to a poor metal abundance. However, if resonance scattering makes the effective optical depth for the absorption sufficiently large, ASCA data are consistent with the "cosmic abundance". This assumption is based on the three O-stars data by ASCA, whose abundances derived by the simple analysis are surprisingly similar. This arguments on the resonance scattering should be confirmed by more samples of early type stars.

CO-INVESTIGATORS
CO-I NAME INSTITUTE COUNTRY
KEN'ICHI TORIIOSAKA UNIVERSITYJAPAN
SHOUKO TANAKAOSAKA UNIVERSITYJAPAN
KUMI YOSHITAOSAKA UNIVERSITYJAPAN

TARGETS

TARGET NAMEPRIRADECTIMETCOFFGISSIS CNTOBS
1)15 MON
2
100.2442 9.8957 40 ksN
Y
P
0.30000
1
2)9 SGR
2
270.9679-24.3607 40 ksN
Y
P
0.10000
1