Routing (electronic design automation)

X-ray binary

Galaxy

Stellar black hole

Star formation

Stellar mass

Astrophysics

Computer science

Intermediate-mass black hole

Computer network

Binary star

Binary black hole

Routing protocol

Physics

Stellar mass loss

Mathematics

Astronomy

Link-state routing protocol

Metallicity

Solar mass

Gravitational wave

Stellar evolution

Neutron star

Black hole (networking)

Astrometry

Binary number

Stars

Spin-flip

Arithmetic

Science

A heavy black hole in an x-ray binary If a black hole interacts with a binary companion star, the system emits x-rays and can form a radio jet. The masses of black holes in these x-ray binaries are all lower than those detected using gravitational waves, challenging models of black hole formation from massive stars. Miller-Jones et al. used radio astrometry to refine the distance to Cygnus X-1, a well-studied x-ray binary. They found a larger distance than previous estimates, raising the mass of the black hole in the system to 21 solar masses. The results challenge the wind mass loss rates implemented in stellar evolution models. Science , this issue p. 1046

Cygnus X-1 contains a 21–solar mass black hole—Implications for massive star winds