December 3, 2007 Infrared imaging technology on NASA's Spitzer Space Telescope has been used to locate some of the youngest solar systems yet detected. Astronomers at the University of Michigan made the discovery when using the telescope to more closely observe gaps in protoplanetary disks of gas and dust surrounding the young stars UX Tau A and LkCa 15 in the Taurus star formation region.
Gaps in the protoplanetary disks were previously attributed to photoevaporation – the heating and subsequent evaporation of material. However, information gathered by the Spitzer Space Telescope has led researchers to believe these particular gaps are instead caused by infant planets sweeping areas clear of debris.
The infrared orbiting telescope observes energy at wavelengths invisible to optical telescopes, and allowed astronomers to study "pre-main sequence stars" in a deeper way. A main sequence star is an average adult star, like the sun, which burns by converting hydrogen into helium. Pre-main sequence stars like UX Tau A and LkCa 15 haven't yet established this conversion process. They derive energy from gravitational contraction. UX Tau A and LkCa 15 are both about one million years old. Our sun, for comparison, is a middle-aged star at 4.5 billion years old.
A paper on the findings by astronomy doctoral student Catherine Espaillat, professor Nuria Calvet, and their colleagues is published in the Dec. 1 issue of Astrophysical Journal Letters.
Professor Nuria Calvet at the University of Michigan said this research adds new insights to the study of solar systems. “We are looking for our history," Calvet said. "We are looking for the history of solar systems, trying to understand how they form." The paper which contains this research is called "On the Diversity of the Taurus Transitional Disks: UX Tau A & LkCa 15."
The US$800 million Spitzer Space Telescope was launched in 2003, and is the first observatory to capture light from extrasolar planets. It uses an Infrared Array Camera, an Infrared Spectrograph and a Multiband Imaging Photometer to gather data. NASA's Jet Propulsion Laboratory, Pasadena, California, manages the Spitzer Space Telescope mission for NASA's Science Mission Directorate. Science operations are conducted at the Spitzer Science Center at the California Institute of Technology, also in Pasadena.
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