Feature of the Month Archive

Professor James Kaler Awarded 2008 AAS Education Prize

Professor Emeritus of Astronomy James B. Kaler

James B. Kaler, Professor Emeritus of Astronomy at the University of Illinois at Urbana-Champaign, has been award the 2008 Education Prize by the American Astronomical Society (AAS). The AAS is a national association of about 6500 professional astronomers, including many around North America and overseas.

As stated by the official citation, Prof. Kaler was awarded the Prize "for significant contributions to many aspects of astronomy education throughout his entire career; for his inspired teaching and mentorship of graduate and undergraduate students, many of whom have gone on to noteworthy careers in the field; for his wider contributions to introductory astronomy education through his textbooks and many engaging astronomy books; for maintaining a popular website with a wealth of useful material regularly consulted by astronomy teachers and students; and for his contributions to the public understanding of astronomy through his prodigious number of public lectures, his work with planetarium, television, and radio programs, and for his numerous books and articles for amateur astronomers as well as the general public."

The AAS established its annual Education Prize in 2001 in order to "recognize outstanding contributions to the education of the public, students and/or the next generation of professional astronomers."

Credits: photo by Bill Wiegand

Embryonic Star Captured With Jets Flaring

A rare, infrared view of a developing star and its flaring jets taken by NASA's Spitzer Space Telescope. In visible light, this star and its surrounding regions are completely hidden in darkness.

Multimedia Features:  • Visible and infrared view  • See video

Astronomers at the University of Illinois have found a developing star wrapped in a black cocoon of dust and sprouting giant jets of gas in a new image from NASA's Spitzer Space Telescope. The stellar portrait, captured in infrared light, offers the first glimpse at a very early stage in the life of an embryonic sun-like star -- a time when the star's natal envelope is beginning to flatten and collapse, and streams of gas are escaping.

"We are seeing this object in the early stages of stellar birth," said Professor Leslie Looney, the lead author of a paper accepted for publication in Astrophysical Journal Letters. "Eventually, the protostar will form into a star much like our sun, and the disk will form into planets and moons."

Located about 800 light-years away, the object is obscured by dust and therefore invisible to the eye. However, the Spitzer Space Telescope's sensitive infrared camera can penetrate the dust, and reveal the structures within. The brightest structure consists of an enormous, almost linear flow of shocked molecular hydrogen gas erupting from the protostar's two magnetic poles. These bipolar jets are so long, light would take about 1 1/2 years to travel from one end to the other.

In star-formation theory, a cloud of gas and dust collapses to form a star and its planets. As the cloud collapses, it begins to rotate faster and faster, like a pirouetting ice skater pulling in her arms. The force of the growing magnetic field ejects some of the gas and dust along the magnetic axis, forming the bipolar jets seen in the photograph.

"If material was not shed in this fashion, the protostar's spin would speed up so fast it would break apart," Looney said.

The flattened envelope around the fledgling star is perpendicular to, and roughly centered on the polar jets. There, seen in silhouette against a bright background of galactic infrared emission, is the flattened disk of a circumstellar envelope.

"Some theories had predicted that envelopes flatten as they collapse onto their stars and surrounding planet-forming disks," Looney said, "but we hadn't seen any strong evidence of this until now."

With Looney, co-authors of the paper are Illinois alumnus John Tobin (now at the University of Michigan) and graduate student Woojin Kwon.

The Spitzer Space Telescope is operated by the Jet Propulsion Laboratory at the California Institute of Technology. Funding was provided by NASA.

Credits: NASA/James E. Kloeppel (Illinois News Bureau), Image/multimedia credit: NASA/JPL-Caltech/UIUC

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