The U.S. National Aeronautics and Space Administration's (NASA) Spitzer Space Telescope unraveled the infrared mystery of baby stars that has bemused astronomers.
In the 1980s, a space-based observatory Infrared Astronomical Satellite (IRAS) mission was launched to survey baby star systems and measure the infrared light they emitted from the protoplanetary disk of gas and dust. After analysis of the measurements, they found that the baby star systems were emitting too much infrared radiation.
Further infrared observations and analyses and refined models have suggested that the simple "flat" formation of protoplanetary disks may need to be revisited. After numerous revisions of the theoretical models, which included a modification of the classic protoplanetary disk and addition of a halo dusty material enclosing the hot baby star, they found that more dust is heated compared to the disk scenario. This could explain the excess infrared radiation emitted by the baby stars.
However, by using NASA's Spitzer and new 3-D models, researchers were able to come up with a better explanation on the cause of this excessive radiation. They found that as the star-forming cloud collapses, a new star does not only retain the angular momentum of the spinning cloud, it also collapses any magnetic fields in it. The magnetic fields will then pass through the protoplanetary disk, which in turn creates huge loops, traps gas, dust and plasma, and enhances the disk's atmosphere.
The huge loops, which rise beyond the sun's photosphere, block the starlight, which in turn, heats the loop and allow it to generate more infrared radiation. That explains the excess the baby star systems are getting.
"If you could somehow stand on one of these planet-forming disks and look at the star in the center through the disk atmosphere, you would see what looks like a sunset," said Neal Turner of NASA's Jet Propulsion Laboratory, Pasadena, Calif. in a news release.
"The starlight-intercepting material lies not in a halo, and not in a traditional disk either, but in a disk atmosphere supported by magnetic fields. Such magnetized atmospheres were predicted to form as the disk drives gas inward to crash onto the growing star," Turner added.
