WROSAT was a German Aerospace Center-led satellite X-ray telescope, with instruments built by West Germany, the United Kingdom and the United States. It was launched on 1 June 1990, on a Delta II rocket from Cape Canaveral, on what was initially designed as an 18-month mission, with provision for up to five years of operation. ROSAT actually operated for over eight years, finally shutting down on 12 February 1999.
WRX J0806.3+1527 or HM Cancri (sometimes shortened to HM Cnc or J0806 after establishing identity) is an X-ray binary star system about 1,600 light-years (490 pc; 1.5×1016 km) away. It comprises two dense white dwarfs orbiting each other once every 321.5 seconds (in this system the "year" duration is of only 5.4 minutes), at an estimated distance of only 80,000 kilometres (50,000 mi) apart (about 1/5 the distance between the Earth and the Moon). The two stars orbit each other at speeds in excess of 400 kilometres per second (890,000 mph). The stars are estimated to be about half as massive as the Sun. Like typical white dwarfs, they are extremely dense, being composed of degenerate matter, and so have radii on the order of the Earth's radius. Astronomers believe that the two stars will eventually merge, based on data from many X-ray satellites, such as Chandra X-Ray Observatory, XMM-Newton and the Swift Gamma-Ray Burst Mission. These data show that the orbital period of the two stars is steadily decreasing at a rate of 1.2 milliseconds per year as they thus are getting closer by approximately 60 centimetres (2.0 ft) per day. At this rate, they can be expected to merge in approximately 340,000 years. With a revolution period of 5.4 minutes, RX J0806.3+1527 is the shortest orbital period binary system currently known.
WRX J0822−4300, often referred to as a "Cosmic Cannonball", is a radio-quiet neutron star currently moving away from the center of the Puppis A supernova remnant at over 3 million miles per hour, making it one of the fastest moving stars ever found. Astronomers used NASA's Chandra X-ray Observatory to observe the star over a period of five years to determine its speed. At this velocity the star will be ejected from the galaxy millions of years from now.
WRX J0852.0−4622 is a supernova remnant. The remnant is located in the southern sky in the constellation Vela ("sail"), and sits inside the much larger and older Vela Supernova Remnant. For this reason, RX J0852.0−4622 is often referred to as Vela Junior.
WRX J1242.6−1119A is an elliptical galaxy located approximately 200 megaparsecs from Earth. According to current interpretations of X-ray observations made by the Chandra X-ray Observatory and XMM-Newton, the centre of this galaxy is a 100 million solar mass supermassive black hole which was observed to have tidally disrupted a star. The discovery is widely considered to be the first strong evidence of a supermassive black hole ripping apart a star and consuming a portion of it.
WRX J1347.5–1145 is one of the most massive galaxy clusters known discovered in X-rays with ROSAT. As a result, it is also one of the most X-ray-luminous because of its hot gas content. The object resides roughly 5 billion light-years away from the Solar System in the constellation of Virgo. Redshift was noted as z=0.451 with an X-ray luminosity of 1045 ergs s−1 in a paper from 2002. In 2013, one study found eight cases of the same object resulting from the intense gravitational bending of light, which makes it possible to identify a series of remote galaxies located inside the galaxy cluster with calculations from the photometric method between 5.5 and 7.5. That study made use of data from Cluster Lensing and Supernova survey with Hubble (CLASH) as well as other sources. The colors in the galaxy cluster are known to correspond with the level of brightness, or the number of electrons trapped in the examined wavelength range of the cluster, with the colors Red, Orange, and yellow as light, Blue-Green, Green-Medium-Light, Blue, and Violet dark, and is considered one of the brightest objects that is known by X-ray.
WRX J1856.5−3754 is a nearby neutron star in the constellation Corona Australis. It is the closest neutron star to Earth yet discovered.