Alternate Names

Nova Ophiuchi 1977, V2107 Ophiuchi, XN Oph77

Type

Stellar mass

Location

In the constellation Ophiuchus

Distance

27,000 light-years

Mass

5 to 7 times the mass of the Sun

Size

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

Discovery Methods

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

Artist's concept of an X-ray binary system like H1705-25. The companion star, at left, is so close that it dumps gas toward the black hole, forming a hot accretion disk. The disk is color coded to show temperature, with orange the coolest and blue and white the hottest. [NASA/CXC/M.Weiss]

This document was last modified: January 13, 2011.