National Radio Astronomy Observatory | 2015 Dec 21
Using new images that show unprecedented detail, scientists have found that material rotating around a very young protostar probably has dragged in and twisted magnetic fields from the larger area surrounding the star. The discovery, made with the National Science Foundation's Karl G. Jansky Very Large Array (VLA) radio telescope, has important implications for how dusty disks -- the raw material for planet formation -- grow around young stars.
The scientists studied a young protostar about 750 light-years from Earth in the constellation Perseus. Their observations, made in 2013 and 2014, measured the alignment, or polarization, of radio waves emitted by material, mostly dust, falling into a burgeoning disk orbiting the young star. The polarization information revealed the configuration of magnetic fields in this region near the star.
"The alignment of magnetic fields in this region near young stars is very important to the development of the disks that orbit them. Depending on its alignment, the magnetic field can either hinder the growth of the disk or help funnel material onto the disk, allowing it to grow," said Leslie Looney, of the University of Illinois at Urbana-Champaign.
As material from the envelope of dust and gas surrounding the young star falls inward toward the rotating disk, it is likely to drag magnetic field lines with it. Because of this, the structure of the magnetic field near the star will become different from the field's structure farther away. ...
High Resolution 8 mm and 1 cm Polarization of IRAS 4A from
the VLA Nascent Disk and Multiplicity (VANDAM) Survey - Erin G. Cox et al
- Astrophysical Journal Letters 814(2):L28 (2015 Dec 01) DOI: 10.1088/2041-8205/814/2/L28
arXiv.org > astro-ph > arXiv:1511.00685 > 02 Nov 2015