GQ Lupi b is the largest exoplanet, with a radius 3.5 times Jupiter's. UY Scuti is the largest star, 1,700 times larger than the sun
Quasars are extremely luminous objects found in galaxy centers. They can outshine all stars in their host galaxies. Quasars are among the most distant and luminous known objects
Ton 618 contains possibly largest black hole at 66 billion solar masses. APM 08279+5255 has largest black hole estimated at 10-23 billion solar masses. Several galaxies and star clusters believed to be around black holes. Sagittarius A* is located in center of Milky Way
Black hole is a region where gravity prevents matter and light escape. Event horizon marks boundary where nothing can escape. Black holes emit Hawking radiation with temperature proportional to mass
Stars form from collapsing molecular clouds containing up to 6 million solar masses. Protostars settle into equilibrium as main-sequence stars over millions of years. Brown dwarfs form when protostars under 0.08 M☉ fail to fuse hydrogen
Pulsars are highly magnetized rotating neutron stars emitting electromagnetic radiation. They have regular pulses ranging from milliseconds to seconds. Pulsars emit radiation only when pointing toward Earth