The Chinese Academy of Sciences (CAS) on Thursday released a batch of scientific discoveries made by the country's Einstein Probe (EP) astronomical satellite, which has been officially renamed the Tianguan Satellite after the Tianguan binary star in commemoration of ancient Chinese astronomical achievements.
The Tianguan Satellite was successfully launched in January 2024 from the Xichang Satellite Launch Center in southwest China's Sichuan Province, with the goal of discovering and studying transient celestial objects. These transient celestial objects are intense explosive phenomena in the universe, akin to fleeting cosmic "fireworks." These spectacular and wondrous "fireworks" carry crucial information about the formation and evolution of celestial objects, and are significant for studying extreme phenomena in the universe and exploring its mysteries.
Yuan Weimin, principal investigator of the Tianguan Satellite mission and a researcher at the National Astronomical Observatories of the Chinese Academy of Sciences (CAS), said that the satellite was renamed to embody the enduring spirit of exploration that the Chinese have had for the vast universe throughout history.
He noted that China is one of the earliest countries in the world to conduct observations of transient celestial objects. There have been records of transient objects such as novae and supernovae since as early as the Han Dynasty (202 BC - 220 AD). In 1054 AD, China documented a supernova explosion event located near Tianguan in the zodiac constellation of Taurus.
"In ancient times, astronomical phenomena like supernovae and novae were referred to as 'guest stars,' so the supernova 1054 is also known as the 'Guest Star of Tian Guan.' The 'Guest Star of Tian Guan' is a very famous supernova discovered by ancient Chinese scientists, and its records are very detailed, making significant contributions to both Chinese and world astronomy," said Yuan.
During its on-orbit operations, the Tianguan Satellite conducted continuous dynamic space surveys and successfully captured the images of a diverse range of transient celestial objects, including stars, white dwarfs, neutron stars, black holes, gamma-ray bursts, and supernovae. Their durations of activity ranged from several seconds to several months.
"We have discovered around 60 very strong transient celestial objects, close to a thousand other (potential) transient objects, and nearly 500 stellar flares," said Yuan.
The satellite, with its expansive and deep field of view, has successfully detected transient celestial objects beyond the Milky Way, including signals from an astonishing 25.6 billion light-years away. This discovery marks the most distant object captured by the satellite to date, showcasing its capabilities in exploring the far reaches of the universe.
"This celestial objects originates from a gamma-ray burst event in the early universe. The Tianguan Satellite observed a radiation burst that lasted nearly 1,000 seconds, while other international gamma-ray burst satellites detected only a 50-second burst. Therefore, this satellite can provide observational data that previous satellites could not capture, revealing more previously unknown physical processes and giving us the opportunity to study astronomical events from even more distant regions of the universe," said Yuan.
The Tianguan Satellite has also discovered a potential new type of transient celestial object, which emitted faint radiation concentrated in the X-ray spectrum for approximately 10 days, challenging detection by other telescopes. Experts highlight that this finding significantly enriches human being's understanding of the universe.
Furthermore, leveraging its expansive observational capabilities, the satellite has produced China's first all-sky X-ray map, marking a remarkable advancement in the country's exploration of the dynamic universe.
China renames astronomical satellite, releases its scientific discoveries
