SUMMARY OF PROPOSAL 72042

DR ROBIN H.D. CORBET
CORBET@LHEAMAIL.GSFC.NASA.GOV

NASA GODDARD SPACE FLIGHT CENTER/USRA
GREENBELT ROAD
GREENBELT
MD USA 20771
Tel: 301 286 2851 Fax: 301 286 1684
Medium: CD ROM
Subject: X-RAY BINARIES

THE SPECTRUM AND POSITION OF THE NEW PULSAR XTE J1855-026


ABSTRACT

XTE J1855-026 was discovered during RXTE PCA slews of the Galactic plane. Followup PCA observations showed pulsations at a 362 second period and enabled a moderately accurate position to be determined. With this position, it was then possible to obtain an ASM light curve which showed a, presumably orbital, modulation at a period of 6.1 days. The source had first been suspected to be a Be star system. However, this combination of pulse and orbital periods is more typical of a supergiant wind accretion driven system. We propose here to study the spectrum, in particular the iron line, and refine the position of the source. The iron line properties will help determine whether this is a supergiant or Be type system. The improved position will aid in searches for the optical counterpart.

CO-INVESTIGATORS
CO-I NAME INSTITUTE COUNTRY
FRANK MARSHALLGSFCUSA
ANDREW PEELEGSFC/NRCUSA
TOSHIAKI TAKESHIMAGSFC/USRAUSA

TARGETS

TARGET NAMEPRIRADECTIMETCOFFGISSIS CNTOBS
1)XTE J1855-026 (MAX)
B
283.9250 -2.6167
20 ks
Y
N
P
0.40000
1
2)XTE J1855-026 (MIN)
B
283.9250 -2.6167
20 ks
Y
N
P
0.10000
1

TARGET 1

OBSERVATIONS TO BE OBTAINED AT PREDICTED MAXIMUM OF ORBITAL LIGHT CURVE FROM RXTE ASM.
Epoch: 50289.1190 Period: 6.07400000 Min: 0.8600Max: 0.9400

TARGET 2

OBSERVATIONS TO BE OBTAINED AT PREDICTED MINIMUM OF ORBITAL LIGHT CURVE FROM RXTE ASM. ORBITAL EPEHMERIS IS FROM A SINE WAVE FIT TO LIGHT CURVE.
Epoch: 50289.1190 Period: 6.07400000 Min: 0.6200Max: 0.6900