The Gemini South, one of the world’s most powerful optical telescopes, has received a major boost to its star-gazing capabilities with the installation of a new high-resolution spectrograph named GHOST (Gemini High-resolution Optical SpecTrograph).
Based in Chile, the scientific instrument is set to widen our understanding of the Universe’s earliest star formations, chemical fingerprints of distant planetary systems as well as the formation and evolution of galaxies.
The cutting-edge technology has been developed and managed by a multi-national team of experts from Australian Astronomical Optics-Macquarie based at Macquarie University, the Australian National University, the US National Science Foundation’s NOIRLab and the National Research Council of Canada.
The newly operational instrument has achieved ‘first light’, observing and capturing HD 222925 – a horizontal branch star about 1,470 light years away in the southern constellation Tucana.
Tony Farrell, Software Technical Lead from Australia Astronomical Optics-Macquarie says GHOST will expand the types of science the Gemini Telescope can accomplish.
“GHOST’s extremely high-resolution viewing capabilities will allow astronomers to get much more detail from their observations. The spectrograph’s ability to view HD 222925 is a prime example of this,” says Mr Farrell.
“The reason Gemini didn’t have this type of instrument before was due to a design feature of the telescope which causes the instruments to move and flex in ways that make instruments of this type impractical.”
The team has solved this long-standing problem by using an optical cable feed from the Gemini telescope to the large and very stable GHOST technology located in a room well underneath the telescope. Ultimately, this remoteness allows an instrument to be built which is both extremely physically and temperature stable
“The result is a spectrograph which is stable within fractions of micro-meters. At the telescope, there are two input probes on a robotic system, feeding the optical cable, which allows observations of two stars to take place at the same time, doubling the efficiency of the telescope compared to common solutions,” says Mr Farrell.
Australian Astronomical Optics-Macquarie leads the GHOST team, which includes the Australian National University (ANU) leading the instrument control system and data reduction software, the National Research Council of Canada (NRC) for the construction of the spectrograph, and the US National Science Foundation’s NOIRLab which manages the International Gemini Observatory.
“GHOST is primarily designed to help astronomers measure the abundance of a large number of elements in the spectra of stars, more efficiently than other large telescopes. By taking precise, high resolution spectra, it will also be able to measure the reflex motion of stars due to the effects of exoplanets,” Professor Michael Ireland from the ANU Research School of Astronomy and Astrophysics.
“The Big Bang only produced Hydrogen and Helium, with a tiny amount of other light elements. GHOST will measure the elements formed in the first supernovae in the Universe, by measuring the spectra of the oldest stars.”
“Early elements produced in supernovae and retained in the next generation of stars vary between different environments. GHOST can not only measure stars in our Galaxy, but also in small galaxies orbiting our own,” said Professor Ireland.