EMBARGOED UNTIL: 1:00 p.m. (EST) November 9, 2000

PHOTO NO.: STScI-PRC00-35


THE MOTION OF RX J185635-3754 -- THE NEAREST NEUTRON STAR TO EARTH

This photograph is the sum of three Hubble Space Telescope images. 
North is down, east is to the right. The image, taken by the Wide
Field and Planetary Camera 2, is 8.8 seconds of arc across (west to 
east), and 6.6 seconds of arc top-to-bottom (south to north).  An arc 
second is a unit of angular measure.  There are 3,600 arc seconds 
in 1 degree and 360 degrees in a full circle.

All stars line up in this composite picture, except the neutron star, 
which moves across the image in a direction 10 degrees south of east. 
The three images of the neutron star are labeled by date. The proper 
motion is 1/3 of a second of arc per year. The small wobble caused 
by parallax (not visible in the image) has a size of 0.016 seconds 
of arc, giving a distance of 200 light-years.

Credit: NASA and F.M. Walter (State University of New York at Stony
Brook)