LJMU telescope played major role in Gaia 'eye of Galaxy'
The Liverpool Telescope, run by LJMU’s Astrophysics Research Institute, has closed a chapter on one of its most important missions – supporting the European Space Agency’s GAIA spacecraft.
Earlier this month, ESA switched off Gaia, ending a 12-year mission that revolutionised our understanding of the Milky Way galaxy we live in.
Launched in 2013, Gaia was put into a "halo orbit" 1.5 million km from Earth, where it mapped the positions, distances, velocities, and properties of nearly two billion stars and other celestial objects in our galaxy. It has provided us with the largest, most precise multi-dimensional map of our galaxy ever created, revealing the Milky Way's structure and evolution in unprecedented detail.
Gaia uncovered evidence of past galactic mergers, identified new star clusters, contributed to the discovery of exoplanets and black holes, mapped millions of quasars and galaxies, and tracked hundreds of thousands of asteroids and comets.
These amazing discoveries came in part due to Gaia's incredible accuracy. It could measure stellar positions to the nearest five-hundred-millionth of a degree - like using a telescope in London to measure the width of a human hair in Rome.
This level of precision depended in part on accurate tracking of Gaia itself, which is where the Liverpool Telescope and the SARI scientists came in.
ARI became involved in the Gaia Ground-Based Optical Tracking (GBOT) campaign in 2009, four years before Gaia’s launch and mainly used the VLT Survey Telescope at Paranal in Chile, and the Liverpool Telescope (LT) at La Palma in the Canary Islands.
Dr Jon Marchant, ARI liaison with GBOT, designed the program the telescope followed: “The Liverpool Telescope took about 20 exposures of Gaia every night with its main camera. The raw images were processed the next morning in Liverpool, and then sent to other GBOT astronomers at the Observatoire de Paris in France.
“Astronomers there used an idea of ours to automatically detect Gaia in the images and help streamline the Gaia position-making pipeline. Gaia's position was routinely measured to the nearest 150 metres - like measuring to the nearest millimetre from 10 kilometres away.
This data, plus that provided by the VST allowed ESA's European Space Operations Centre in Germany to calculate Gaia’s exact path, which ultimately helped to refine the Gaia catalogue’s amazing precision.
Gaia itself is now drifting slowly and silently away from Earth space. Before being switched off last week, it was boosted out of halo orbit and is now moving around the Sun in an orbit a little larger and slower than the Earth's. It will swing by the vicinity of Earth every 14 years or so, though by design no closer than 10 million kilometres so that it doesn't interfere with future space missions.
“Gaia and tracking Gaia was an amazing feat of science and engineering, which has given us so much more understanding of our galaxy,” added Jon.
For more on this story, see an article written by Dr Marchant in The Conversation.
* The Conversation article = https://theconversation.com/how-were-helping-the-gaia-mission-map-a-billion-stars-to-unparalleled-precision-65602
About the Liverpool Telescope:
The Liverpool Telescope came online in 2004, and though based in the Canary Islands, it's run by LJMU’s Astrophysics Research Institute in Liverpool. The LT is fully robotic - with no human intervention it decides for itself what to observe, drawing from a database of submitted requests from astronomers around the world. These requests can be dropped into the database at any time, so astronomers can spread out their allocated time throughout the semester any way they like. This unique flexibility for a professional telescope of this size made it perfect for tracking Gaia.
