Artist's impression of a protoplanetary disk around a luminous young star. Dust particles in the disk that orbit around the star may eventually coalesce to form new planets. Research by the RPI team will provide new insight into the chemical evolution of the disks. Image credit: European Southern Observatory

The New York Center for Astrobiology will widen the scope of its search for the building blocks of life beyond Earth with the help of a new NASA grant. Based at Rensselaer Polytechnic Institute, the center is devoted to investigating the origins of life on Earth and the conditions that lead to formation of habitable planets in our own and other solar systems.

“We are looking for the conditions of life, rather than life itself,” said Douglas Whittet, director of the New York Center for Astrobiology and a Rensselaer professor of physics, applied physics, and astronomy. The center opened in 2008 with support from NASA.

One interesting finding from its research thus far is that stars aid in the process of forming the more complex matter found on planets and in life.

“You need energy to drive the chemistry. A star itself can cook simple molecules into something more interesting,” Whittet said.

The new four-year $630,000 grant will allow the center to expand operations.

“It will allow us to support some more collaborations, which in turn lets us acquire and analyze more data,” Whittet said.

Researchers at the center study the chemical, physical, and geological conditions on Earth that gave birth to life. That information, in turn, is used to search for similar conditions elsewhere – on Mars and other bodies in our solar system, and on planets orbiting other stars.

“A lot of organic molecules present on Earth may have been delivered shortly after it was formed. The evidence for this comes from meteorites, which contain amino acids,” Whittet said. “We aim to find out what was happening in the solar system 4.5 billion years ago when it was formed. When and how was this matter synthesized, and how common is it?”

The researchers look for clues within young solar systems, where stars are surrounded by molecular clouds or pre-planetary disks that have not yet coalesced into planets.

The key to their research is spectroscopy — or light signature — of the clouds and disks. The early universe was composed of hydrogen and helium, from which other elements were formed, and later combined into molecules in interstellar clouds. By examining the light signature of the material, researchers can determine which chemicals are present in a particular cloud or pre-planetary disk.

 “You use the star as a source of radiation. The material between you and the star is absorbing some of it. We look at the absence of light caused by the material,” Whittet said.

Whittet said researchers are currently analyzing data gathered from the Spitzer Space Telescope — an infrared telescope orbiting the sun that gathered data from 2003 to 2009.

“There’s a huge archive of data that’s being analyzed, and the grant will afford us access to more of that material,” Whittet said.

Already that material has yielded the insight that stars play a role in the creation of more complex matter. Whittet explained that molecular clouds around stars mature into pre-planetary disks and then planets. Complex matter is found in increasing abundance as the stages progress.

“Organic molecules such as hydrocarbons and alcohols are more common in pre-planetary disks compared with molecular clouds,” Whittet said. “These molecules form with the help of energy from the star.”

A less promising finding — at least from the standpoint of finding life elsewhere in the universe — is the relative scarcity of complex hydrocarbons.

“The most common material we’ve found is carbon dioxide, which is not very useful in making life,” Whittet said. “It would be a lot more interesting if the carbon were going into hydrocarbons, which are a stepping point to much more complicated molecules.”

Contact: Mary L. Martialay
Phone: (518) 276-2146
E-mail: martim12@rpi.edu