Two-Ton Gemini Planet Imager Arrives at Notre Dame for Upgrades | News | Notre Dame News

Gemini Planet Imager Delivery (Photo by Matt Cashore/University of Notre Dame)

A key to potentially finding habitable planets lies in the Nieuwland Hall of Science at the University of Notre Dame, after a long journey.

Packed in six crates – one of which was only half an inch smaller than the width of a jumbo jet door – the Gemini Planet Imager (GPI) arrived in Notre Dame after a trip from its location several hours north of Santiago, Chile. It traveled through Atlanta, then Chicago, and finally Elkhart, Indiana, before being loaded onto a tractor-trailer bound for South Bend, Indiana.

It’s fair to say that Jeffrey Chilcoteassistant professor at Department of Physics and Astronomywho is leading an equipment revamp and upgrade project, was apprehensive about the instrument’s journey – but he was also excited to get started, as it’s been 14 years since GPI went into service and seven years since it has been installed.

“GPI was designed and built with a bunch of (educated) guesswork in mind,” he said. “Now we can reconfigure it and get absolutely cutting-edge science.”

Once Chilcote and its collaborators complete the upgrades – at which time the instrument will be known as GPI 2.0, in late 2023 or early 2024 – the instrument will be installed at Gemini North in Mauna Kea, Hawaii, l twin observatory of that of Chile.

The instrument was built by a consortium of U.S. and Canadian institutions with Chilcote and Quinn Konopacky, associate professor of physics at the University of California, San Diego, as well as astrophysicists from Stanford University, University Cornell and Herzberg Astronomy and Astrophysics in Victoria, British Columbia. , Canada. The GPI had been mounted on the Gemini South Observatory Telescope in Chile since 2013, where it assisted in the search for Jupiter-like planets until it was removed in August 2020. The instrument was due to arrive in South Bend in 2020, but the global coronavirus pandemic has delayed plans.

In 2017, Chilcote and others approached the wider astronomy community to ask what kinds of upgrades should be made. “We asked, ‘What do you need, at a minimum, to take your science to the next level, now that you’ve learned what directions might be worth pursuing?’ “, did he declare.

The first iteration of GPI allowed astronomers to observe large, hot planets through their infrared light, as well as faint discs of dust from comets and asteroid belts in distant solar systems. The upgrade will allow astronomers to see lower mass planets that orbit closer to their stars.

“We were limited to what are called ninth-magnitude stars, so with these enhancements we’re going to be looking at what are called 14th-magnitude stars, which are about 100 times dimmer,” Chilcote said. The brightest stars in the sky are considered first magnitude, while the darkest to the naked eye are sixth.

The logistics of removing the GPI from the Gemini in Chile were quite tricky, but by the time it arrived in Indiana, the day was expected to have near zero chance of precipitation. Although the telescope is open to the air when assembled, its parts cannot tolerate rain (or snow; originally GPI was due to arrive during the winter months).

Chilcote and others gutted parts of the Nieuwland machine shop, and they had to purchase a specific type of crane that fit into the ground floor rooms, but was still able to hold the two and a half ton instrument. On a beautiful sunny day in June, a team moved the boxes from the truck to Nieuwland. The smaller crates fit through the door, but the larger one was never expected to fit inside the crate. Chilcote and others opened the crate and, using heavy equipment, turned GPI on its side to get it through the door.

He found himself holding his breath. A lot. Fortunately, the transfer went well.

Researchers have discovered more than 5,000 extrasolar planets, Chilcote said, but most were detected using the transit method. With this method, scientists must detect slight variations in the brightness of a star, caused when a planet passes in front of it. Others were detected using the so-called “wobble” method, or radial velocity method, where scientists detect changes in the star’s spectrum using Doppler. But GPI finds planets by imaging them directly, based on the star’s glare. The GPI allows astronomers to measure a planet’s size, temperature, and even composition using spectroscopy.

By the time the GPI Exoplanet Survey team reached its 2019 goal of characterizing exoplanets, more than 500 nearby stars had been surveyed. The instrument discovered seven new debris disks as well as 51 Eridani b, a Jupiter-like planet in the constellation Eridanus that takes 32 Earth years to complete its star’s orbit. The instrument also discovered the brown dwarf/gas giant exoplanet HR 2562 B in 2016, currently known as the most massive exoplanet discovered.

The project is funded by the National Science Foundation Major Research Instrumentation Program and the Heising-Simons Foundation. In addition to Notre Dame, the University of California, San Diego, Herzberg Astronomy and Astrophysics, Cornell, the Gemini program, the Space Telescope Science Institute, and the University of California, Santa Cruz also contributed to the construction and research of the instrument. .

Contact: Jessica Sieff, 574-631-3933, [email protected]


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