Eleven years ago, a team of New Mexico Tech scientists began a research program to design an instrument that could detect the atmospheric makeup on planets 10 to 100 light-years out in space. The result was the New Mexico Exoplanet Spectroscopic Survey Instrument or NESSI for short. NESSI was initially designed to be used at the Magdalena Ridge Observatory, but once the researchers began using it in April 2014, the instrument didn't work as expected.
That has changed, and the Tech born instrument is now successfully collecting the data for which it was designed.
An article published last week by NASA’s Jet Propulsion Laboratory in Pasadena said that scientists at the Hale Telescope in California have been testing NESSI since it was installed there in 2018.
So far, the article states, NESSI “has checked out two ‘hot Jupiters,’ massive gas giants orbiting close to their stars and too scorching to sustain life. NESSI observed these planets crossing their host stars, proving the instrument would be able to help confirm possible worlds previously observed by other telescopes. Now it is ready for more detailed studies of distant cousins of our solar system. And while the instrument is designed to look at planets much more massive than Earth, NESSI's methods could be used to search for Earth-size planets someday as well once future technologies become available.”
"NESSI is a powerful tool to help us meet the family," said Mark Swain, an astrophysicist and the JPL lead for NESSI. "Twenty-five years ago, to our best knowledge, we thought we were alone. Now we know that - at least in terms of planets - we're not, and that this family is extensive and very diverse."
NESSI began as a concept in 2008 when Swain visited Michelle Creech-Eakman's astrobiology class at New Mexico Tech. Over coffee, Swain told his colleague about exoplanet observations he had done with a ground-based telescope that didn't turn out well. Creech-Eakman realized a different instrument combined with the right telescope could accomplish Swain's goals. On a napkin, the two sketched an idea for what would become NESSI.
Another member of the initial research team was New Mexico Tech astrobiologist Penny Boston, who has been most recently leading a project looking into the possibility of finding microscopic life in lava tubes on Mars.
According to Boston, the whole idea for the project grew out of an astrobiology class taught by Boston, Creech-Eakman, and biology professor Tom Kieft.
JPL’s Swain happened to be involved in one of the classes, “and he was talking about the exoplanet stuff they were starting to do. Looking at planets orbiting other stars,” Boston said in a 2008 interview. "The talk got around to this cutting edge astronomy using ground-based telescopes as opposed to the Hubbell and Spitzer space telescopes."
The JPL article says, “NESSI views the galaxy in infrared light, which is invisible to the human eye. It stares at individual stars to observe the dimming of light as a planet passes in front of its host star - an event called a transit. From the transit, astronomers can learn how big the planet is relative to its host star. When the planet passes directly behind the star and re-emerges, it's called an eclipse. NESSI can look for signatures of molecules from the planet's atmosphere detectable in starlight before and after the eclipse.”
Inside NESSI, devices that focus infrared light spread it into a rainbow, or spectrum, filtering it for particular wavelengths that relate to the atmospheric chemistry of distant planets.
"We can pick out the parts of the spectrum where the molecules are because that's really what we're looking for in the infrared in these exoplanets - molecular signatures of things like carbon dioxide and water and methane to tell us that something is interesting going on in that particular planet," said Creech-Eakman, principal investigator for NESSI at New Mexico Tech.