First direct evidence of early flattening as planets form

William Atkins
Thursday, 13 December 2007 19:58

Science - Space

Illinois astronomers used the NASA Spitzer Space Telescope to show that early in the planet-forming phase a spinning cloud of gas and dust flattens as it begins to develop into a planet. This discovery will help astronomers learn more about how our own Sun looked when it was first born.                

U.S. astronomer Leslie Looney, of the Department of Astronomy at the University of Illinois at Urbana-Champaign, led a group of fellow researchers to this assertion. Their results (“A Flattened Protostellar Envelope in Absorption around L1157”) were published in the November 5, 2007 issue of Astrophysical Journal Letters.

Co-authors of the paper are former undergraduate student John J. Tobin (now at the University of Michigan) and graduate student Woojin Kwon.

According to the University of Illinois (UIUC) article “Astronomers find stellar cradle where planets form,” Looney’s team found the first definite evidence of a spinning and flattening cloud of gas and dust surrounding a young protostar. The reddish cloud will continue to flatten more as the planet-forming cloud takes on a more and more spherical shape. As this happens the cloud will spin (rotate) faster and faster.

As this rotation gathers speed, the magnetic field of the protostar becomes stronger and eventually begins to eject gas and dust along its magnetic axis. This action forms long jets. These two jets of whitish gas, consisting primarily of molecular hydrogen gas, emerge perpendicular but in opposite directions to the magnetic poles of the stellar-forming cloud.

The bi-polar jets are extremely long. In fact, the authors of the study indicate that if one traveled at the speed of light it would take about 1.5 years to traverse from one end to the other end. (The speed of light is approximately 186,000 miles per second, or 300,000 kilometers per second.)

The red areas of the cloud and the white areas of the jets are considered the hottest areas of the formation.

Theory had already predicted how planets form but direct evidence had never been found before.