According to a new study, the ripening time of stars might be significantly shorter than previously thought. Observations by Chinese researchers suggest that a gas cloud develops into a star embryo ten times faster than previously thought.
With the help of the Five-hundred-meter Aperture Spherical radio Telescope (FAST), the largest radio telescope in the world, the scientists examined Lynds gas cloud with its star embryo in 1544. They zoomed in on the pre-stellar core in the Taurus Molecular Cloud, a huge hotbed for stars, only 450 light-years away. In doing so, they discovered that the tiny embryo on which they were focusing forms ten times faster than assumed thanks to weak magnetic fields.
Magnetic forces hold matter in place, slowing down the compression process, which, thanks to gravity, leads to a pre-stellar core that is dense enough to collapse and spark nuclear fusion. Before FAST went into operation last April, researchers examined Lynds 1544 with the weaker Arecibo radio telescope in Puerto Rico. They measured the magnetic fields in the thin gas layers far outside and also the stronger fields inside the core. Magnetic force dominates in the outer layer and gravity in the core because the core is 10,000 times denser than the outer layer. What was missing were measurements in the intermediate area.
Struggle between gravity and magnetic field
This has now been achieved with the FAST, a huge bowl in a natural basin in southwest China. It was found that the magnetic field strength in the intermediate area is not stronger than in the outer layer. “If standard theory worked, the magnetic field would have to be much stronger to withstand a 100-fold increase in cloud density. That’s not the case,” says Di Li, FAST senior scientist and lead researcher.
The battle between gravity and magnetic field is therefore not “won” by gravity in the core, but already in the cloud. “There (in the cloud) the stars form, not in the dense core,” explains Paola Caselli from the Max Planck Institute for Extraterrestrial Physics, which was not involved in the research. “If this is the case in other gas clouds, it will be revolutionary for the star formation community.” (apa)
