NM Tech Exoplanet Search: Is Earth Alone?


SOCORRO, NM (KRQE) – Are the planets that are circling other stars in the Milky Way hospitable enough to support life? It’s one of the most compelling questions in science with many large research institutions across the globe seeking the answer.

Now researchers and students at New Mexico Tech are playing a major role in the quest to reveal what’s in the air on these extra solar worlds called Exoplanets, outside our solar system.

Collaborating with NASA, a New Mexico Tech team recently completed building an instrument called NESSI, that was attached to Tech’s existing 2.4 meter telescope to probe alien worlds in a new way, to reveal the actual chemical composition of their atmospheres.

Analysis of Exoplanet atmospheres may not just reveal whether life can be supported, but also someday, whether life may already exist on some of these worlds. Scientists say if potentially organic compounds like methane are discovered, they may indicate a biological process underway.

New Mexico Tech physics professor, Dr. Michelle Creech-Eakman, is co-investigator for NESSI, the New Mexico Exoplanet Spectroscopic Survey Instrument. She says the $3.5 million instrument is the first purpose-built device for the analysis of exoplanet atmospheres.

Creech-Eakman and her team are looking for exoplanet atmospheres that contain carbon dioxide, or oxygen or methane or water. The kinds of things that we see in our own solar system in the planets.

Almost 3,000 confirmed or suspected exoplanets have been discovered in the Milky Way. However, only a tiny handful have actually been captured in an image through a telescope. The vast majority of exoplanets are invisible to the best telescopes and are only found indirectly.

Discovery of unseen exoplanets is often done either by noting a fade in the light of a star as a planet transits in front of it, or by measuring the ‘wobble’ of the star as unseen planets tug on it during their orbits.

While many telescopes on earth and in space can discover the basic existence of an exoplanet, none were built specifically to reveal the composition of its atmosphere.

That’s where NESSI has a niche. NESSI is a highly advanced near-infrared spectrographic camera system that is specifically designed to capture the chemical fingerprint of an alien atmosphere as the planet transits the face of its sun. NESSI was recently attached to the New Mexico Tech high-power 2.4 meter telescope. The telescope, at Magdalena Ridge Observatory (MRO), can be used by NESSI on a regular basis.

“That combination of a stable, dedicated telescope and the ability to do repeat observations basically at will, allows us perhaps to do some really exciting science,” said Creech-Eakman.

NESSI co-investigator Mark Swain, a NASA/JPL astronomer, sees NESSI as a trailblazing instrument.

“It’s very exciting to have an instrument that was designed from day one to do this job,” he said.

NESSI will capture the spectra of both the star and the planet during the transit and then allow scientists to extract the composition of the planet’s atmosphere. The first targets for NESSI will be the easier to detect, so-called “hot Jupiters”, very large planets that are very close to their stars.

“Sure these planets are really hot and they’re really bright, but they are sitting right next to an even brighter and hotter star,” says New Mexico Tech graduate student Heather Bloemhard.

“So the difference that we’re trying to detect is roughly one percent,” she says. “One percent of the light we see is from the exoplanet and we need to find that one percent of that light, and it’s not easy.”

NESSI uses a complex collection of of lenses and mirrors, to focus the view captured by its host telescope on an ultra-sensitive sensor array. Liquid nitrogen super-cools the instrument package to maximize sensitivity.

“We should be ready to expect the unexpected,” said says Mark Swain. “We should expect that NESSI will discover something we can’t even imagine.”

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