GHOST, a new generation spectrograph that will expand our understanding of stars

GHOST, a new generation spectrograph that will expand our understanding of stars

The Gemini South telescope, operated by NOIRLab, has a high-resolution spectrograph GHOST. It has recently observed its first star, bright and chemically complex, and will be available for scientific research since 2023.

Recently, the Gemini South telescope at the International Gemini Observatory in Chile, operated by NOIRLab, was upgraded by a new generation high-resolution spectrographer.

A few days ago, GHOST reached its first goal: HD 222925, an unusually bright and chemically complex star located more than 1,400 light years away in the direction of the constellation Tucan. This star is an excellent example of the type of object to be studied by GHOST. Jennifer Lotz, director of Gemini, said, "After the new generation of GHOST will become an important component for astronomers."

Gemini South and his new spectrograph

Half of the Gemini International Observatory

Spectrographs are perhaps one of the most important scientific tools in all astronomy. Unlike high-resolution cameras that capture the details of distant stars and galaxies, spectrographs accurately analyse the spectrum of light emitted by these objects, so they can reveal detailed information about chemical composition, motion and rotation.

GHOST, created by an international consortium, is the most sensitive high-resolution spectrograph in the entire optical range of wave lengths among all spectrographs currently operating on telescopes comparable to Gemini South.

  • It has 10 times more spectrographic resolution than GMOS, another large optical spectrograph called Gemini. It will provide follow-up observation of key objects of many ongoing and future research. Among the tools to be used by GHOST data is the Legacy Survey of Space and Time Observatory of Rubin, SkyMapper and GAIA. It is publicly available: any researcher will be able to make proposals for its use for his research. It will be supplemented by a NOIRLab data reduction line for astronomers using it.

Australia ' s astronomical optical company is responsible for the instrument management system and data reduction software.

An excellent example of the type of objects that GHOST can study is HD 222925, which is its first target. In the next image, we see two spectrum GHOST measuring the light of stars between 350 nm and 1015 nm. A more blue light with a wave of 380 nm is ultraviolet and invisible to our eyes. A more red light about 750 nm is infrared, also invisible to our eyes. The dark lines of rainbows are similar to the fingerprints of gas in the star, including hydrogen, calcium, iron and gold.

GHOST will be available from 2023

The design and construction of GHOST began in 2010. It took a good ten years of operation. The tool was installed at Gemini South in early 2022. Now the instrument team has tested GHOST in practice to make sure that its systems work as planned. Once the launch process is completed, GHOST will join other optical and infrared instruments of Gemini South and will be available to the astronomical community. This is expected to happen in the first half of 2023.

Steve Margheim, a GHOST researcher at NOIRLab NSF, speaks of the first star observed by GHOST: ".