Alternate Names

V821 Ara

Type

Stellar mass

Location

In the constellation Ara, the altar

Distance

27,000 light-years

Mass

5.8 to 10 times the mass of the Sun

Size

Diameter 20-35 miles (31-60 km), equal to the size of a large city

Discovery Methods

• Detection of an accretion disk
• Measuring the motions of a companion star

GX 339-4

This artist's concept is looking face-on at the accretion disk that surrounds the black hole in GX 339-4. A streamer of gas from the companion star feeds the accretion disk, while jets of charged particles shoot into space from the poles of the black hole.

An illustration shows hot gas from a low-mass companion star (right) flowing into an accretion disk around the black hole.

This animation shows the link between the optical and X-ray light from GX 339-4. The inset shows optical images of the system, while the tracing shows changes in its infrared energy. They show that the visible light dims shortly before the X-ray energy spikes. The entire sequence covers less than 10 seconds.

This document was last modified: September 21, 2011.