SUMMARY OF PROPOSAL 72021

DR. KOJI MUKAI
MUKAI@LHEAVX.GSFC.NASA.GOV

NASA/GSFC AND USRA

GREENBELT
MD USA 20771
Tel: 301-286-9447 Fax: 301-286-1684
Medium: CD ROM
Subject: CATACLYSMIC VARIABLES

ASCA OBSERVATIONS OF HYDROGEN DEFICIENT CATACLYSMIC VARIABLES


ABSTRACT

A small number of cataclysmic variables show no observable traces of hydrogen. A likely model involves a white dwarf accreting from a Roche-lobe filling, less massive, He white dwarf secondary. The peculiar evolutionary history implied by such a configuration may result in other abundance anomalies, besides the lack of hydrogen. I have analyzed the archival ASCA AO-2 data on one such system, GP Com; I have been able to derive, solely from the X-ray spectrum, overabundances of N and Ne and underabundance of Fe, as previously suggested from optical and UV spectroscopy. I propose to observe the next 3 X-ray brightest hydrogen deficient cataclysmic variables.

CO-INVESTIGATORS
CO-I NAME INSTITUTE COUNTRY

TARGETS

TARGET NAMEPRIRADECTIMETCOFFGISSIS CNTOBS
1)CR BOO
A
207.2308 7.9585
40 ks
N
Y
P
0.15000
1
3)V803 CEN
X
200.9354-41.7422
1 ks
N
Y
P
0.10000
1