The University of Michigan Department of Astronomy is part of an international consortium of institutions that will take part in the design and construction of ANDES, a powerful instrument set to be used on the largest visible-infrared telescope in the world.

The instrument will reveal the nature of atmospheres of planets around nearby stars, rare elements forged in the interiors of stars, the formation of galaxies and even the evolution of the universe itself, according to University of Michigan astronomer Michael Meyer.

The instrument, the ArmazoNes high Dispersion Echelle Spectrograph, a very high resolution spectrograph, is being built for the European Southern Observatory’s (ESO) Extremely Large Telescope (ELT). Its commissioning will begin in 2028. Today, ESO has signed an agreement with the international consortium for ANDES’ design and construction.

“Under the right conditions, it will complete observations more than 1,000 times faster than that of our current flagship facility, the Magellan telescopes, and provide clarity in image resolution more than 15 times that of the Hubble Space Telescope at wavelengths redder than the reddest things the human eye can see,” said Meyer, U-M professor of astronomy.

Formerly known as HIRES, ANDES is an instrument that splits light into its component wavelengths so astronomers can determine important properties about astronomical objects, such as their chemical compositions. The instrument will have an extreme wavelength precision in the visible and near-infrared regions of light and, when working in combination with the powerful mirror system of the ELT, will pave the way for research spanning multiple areas of astronomy.

Additionally, the instrument will be used to search for signs of life in planets around stars other than our sun, to look for the very first stars in the universe, as well as to test variations of the fundamental constants of physics and to measure the acceleration of the universe’s expansion.

“We are currently working on developing advanced techniques to measure things such as wind speeds around a planet and chemical changes from one location to another,” said theoretical astrophysicist Emily Rauscher, U-M associate professor of astronomy. “With the instruments and telescopes that we have right now, we are just scratching the surface of getting at these details.

“With the ANDES instrument, a single observation on one night will give us such a wealth of detailed information about each planet that we’re not even really sure how to interpret those data yet. It’s very exciting that we anticipate such high data quality that we need to do simulations and tests in advance so we are prepared to interpret the measurements once they come.”

ANDES will conduct detailed surveys of the atmospheres of Earth-like exoplanets, allowing astronomers to search extensively for signs of life. It will also be able to analyze chemical elements in rare objects, making it likely to be the first instrument capable of detecting signatures of Population III stars, the earliest stars born in the universe.

“ANDES can also begin the search for potential signatures of life in planets orbiting other stars using telescopes on the ground,” said Ted Bergin, U-M astronomer and chair of the U-M Department of Astronomy. “This will start, in earnest, humanity’s search for whether we are alone in the universe.”

Bergin is a member of the ANDES executive board and science team, U-M astronomer Elena Gallo is a member of the steering committee and science team, and Rauscher is a member of the science team.

“ANDES is an instrument with an enormous potential for groundbreaking scientific discoveries, which can deeply affect our perception of the universe far beyond the small community of scientists,” said Alessandro Marconi of the National Institute for Astrophysics and principal investigator of ANDES.

The European Southern Observatory’s Extremely Large Telescope is currently under construction in the Atacama Desert of Northern Chile.