An artist's concept of a rocky, Earth-size exoplanet in the habitable zone of its host star. (Image: NASA Ames/SETI Institute/JPL-Caltech)
An artist's concept of a rocky, Earth-size exoplanet in the habitable zone of its host star. (Image: NASA Ames/SETI Institute/JPL-Caltech)

UA to Join 'A-Team' in Search for Earthlike Planets

A new NASA initiative is embracing a team approach to the quest for life on planets around other stars.
April 20, 2015
The Large Binocular Telescope Interferometer (green structure in center of frame) between the two 8.4m mirrors of the LBT.  (Credit: LBTO - Enrico Sacchetti)
The Large Binocular Telescope Interferometer (green structure in center of frame) between the two 8.4m mirrors of the LBT. (Credit: LBTO - Enrico Sacchetti)
The Earths in Other Solar Systems research group pursues several angles of research to study which planets could harbor life and why. (Image: Daniel Apai)
The Earths in Other Solar Systems research group pursues several angles of research to study which planets could harbor life and why. (Image: Daniel Apai)

Are we alone?

To get answers to one of humanity's oldest questions, NASA has selected an interdisciplinary research team led by the University of Arizona for a major grant in a new program focusing on the search for clues to life on faraway worlds. As part of this virtual institute — called Nexus for Exoplanet System Science, or NExSS — UA researchers will help understand how Earthlike planets form and which nearby stars are most likely to host Earth's twins.

In bringing together the best and brightest, the NExSS team hopes to better understand the various components of exoplanets — planets around other stars — as well as how the parent stars and neighbor planets interact to support life.

"Participation in the new NExSS program allows us to endeavor on an ambitious program to understand how Earthlike planets form and acquire their water, carbon, and nitrogen budget — in other words, how to equip a planet with the ingredients and processes necessary to sustain life as we know it," said Daniel Apai, who leads the Earths in Other Solar Systems, or EOS, team at the UA.

NASA sees the search for extraterrestrial life as one its most exciting challenges. Since the launch of NASA’s Kepler space telescope six years ago, more than 1,800 exoplanets are known, with thousands of additional candidates waiting to be confirmed. Some of these worlds are potentially habitable, and their presence tells scientists that similar planets also should be common in the solar neighborhood, where astronomers have a chance to search them for signs of life, or biosignatures.

Key to this effort is understanding how biology interacts with the atmosphere, geology, oceans and the interior of a planet, and how these interactions are affected by the host star. NExSS will address this challenge by coordinating research in astronomy, planetary sciences, biology, atmospheric sciences and earth sciences. NExSS will include team members from 10 universities, three NASA centers and two research institutes.

"With our current technologies, we have primarily measured the physical and astronomical properties of exoplanets — such as their masses or sizes, and their orbital properties," said Natalie Batalha, NASA's Kepler mission scientist and co-director of NExSS at NASA. "But the integration described above will be required for a new era of measurements of the chemical properties of these worlds that will determine what they are made of, and detect specific chemicals in their atmospheres."

Building on its decades-long tradition of excellence in astronomy, planetary sciences and space mission development, the UA’s Steward Observatory and Lunar and Planetary Laboratory coordinated an international team to successfully propose complex, five-year interdisciplinary research in NASA’s new Nexus for Exoplanet System Studies program.

The EOS team, which includes 25 investigators, will carry out 14 closely coordinated research projects and combine its results into a comprehensive computer model of planetary system formation, capable of predicting connections between the properties of planetary systems (such as presence of other planets) and the likelihood that they host Earthlike planets. The team will make use of the UA's radio telescopes, the Large Binocular Telescope (the world’s largest optical telescope, located on Mount Graham in southeastern Arizona) and several other cutting-edge telescopes, as well as the UA’s state-of-the-art microscopic facilities. Over the next five years, 13 graduate students and postdoctoral researchers will be able to join the study.

Other institutional partners in the EOS project include the University of Chicago and the Tucson-based National Optical Astronomical Observatory. The NOAO-based team will focus its attention on disks around nearby young stars in its search for answers to some basic questions about planet formation. 

"Using infrared and millimeter wavelength observations, we will look for chemical evidence of planet formation in action and try to better understand the timing of planet formation, when it begins and how long it takes," said Joan Najita, astronomer and NOAO lead. 

In recent years, the UA has established itself as a leader and a key NASA partner in the search for extraterrestrial life. It hosted last year’s largest conference on the search for extraterrestrial life, has multiple world-class teams carrying out research on exoplanets and astrobiology, and also provides training for undergraduate and graduate students in its astrobiology minor programs.

Thomas Zega, EOS deputy principal investigator and assistant professor in the UA's Lunar and Planetary Laboratory, said, "Meteorites are physical relics from the time the solar system formed, and by studying the organics that they contain with high spatial resolution microscopy techniques, we can get insight into pre-biotic chemistry."

Among NASA’s ambitious plans are next-generation major space telescopes developed specifically to survey the atmospheres of extrasolar Earths for gases characteristic to life, and the UA’s exoplanet hunter teams and UA students are now set to be part of the adventure.