Astronomers lead searches for answers to questions of cosmic origins
May 30, 2008
Astronomers Dr. J.D. Smith, left, and Dr. Tom Megeath, shown here in front of UT's Ritter Observatory telescope, will use the infrared space-based telescope Herschel to investigate the origins of stars and galaxies.
University of Toledo researchers Tom Megeath and J.D. Smith have scheduled their time travel for early 2009. The two astronomy professors are key members of two teams using Herschel, the far-infrared space-based telescope, to look back through time to investigate the births of individual stars and the life cycles of galaxies.
This revolutionary observatory will be able to examine the cold universe, objects that don't emit enough visible light to be seen by the human eye and must be studied in infrared light.
Dr. Megeath, assistant professor of astronomy, will be leading a team investigating a vast patch of the constellation Orion, which contains huge, cold clouds of gas that are in fact nurseries of newborn stars. The colorful Orion Nebula is just one small, visible piece of this much larger cloud that Herschel’s infrared detectors will be able to probe. Megeath and his team already discovered 300 protostars — stars still in the process of forming — in the Orion cloud with the Spitzer space telescope, named after Toledo native astrophysicist Lyman Spitzer. It is these protostars that form the basis of the Herschel program.
“Herschel should give us fascinating insights into the origin of our own sun and help answer the question ‘Why did our solar system form the way it did,’” Megeath said. “Is that formation process that created our solar system normal or is the creation of solar systems and planets — particularly planets with life — rare, arbitrary and random?”
Megeath added that the research should help answer stellar “nature vs. nurture” questions.
“There isn’t consensus in the field on what role the environment in which a star is created plays in determining a star’s future. A star’s life cycle is based on its mass, and we’re hoping to learn more about what determines how massive a star will be. Mass determines how bright, how hot and how long a star will exist, as well as the nature of the star’s death,” Megeath said.
Meanwhile, Dr. Smith, assistant professor of astronomy, is pulling back a few 100 million light years to look not at stars, but at several dozen galaxies in the cosmic neighborhood.
“If Tom is looking at the individual houses, the team I’m leading is looking at the cities,” Smith said, explaining that his research is focused on how galaxies relate to each other, why some galaxies “live hard and die young as compared to others that use their fuel at a much slower rate.”
Using the infrared sensors on Herschel, Smith and his team hope to find ways to determine whether galaxies are generating new stars according to the wavelengths of light they emit.
The Herschel telescope will be positioned at a unique and relatively stationary point in space beyond the moon’s orbit. It also has a relatively short planned lifespan, as a limited supply of liquid helium is available to keep the telescope cold, even the icy vacuum of space would make Herschel warmer than the -269 degrees Fahrenheit it needs to operate properly.
As “key projects” for Herschel, both Megeath’s and Smith’s work will help form a foundation of knowledge that will impact astronomy for years to come.
Megeath will lead the Herschel Orion Protostar Survey, which has been allotted 200 hours and includes members from Germany, France, Spain and Canada, as well as the Smithsonian Astrophysical Observatory, the California Institute of Technology, Johns Hopkins University, and the universities of Arizona, Michigan and Rochester.
Smith will lead one of three sub-teams of the 537-hour study KINGFISH, a survey of nearby galaxies that includes members from the United Kingdom, Germany, France, the Netherlands, Canada and Italy, as well as the Space Telescope Science Institute in Baltimore, the California Institute of Technology, Princeton University, and the universities of Arizona, Maryland, Wyoming and Massachusetts.
Herschel will be launched by the European Space Agency from French Guiana on an Ariane-5 rocket in January.