The apple, that is Atacama large millimeter/submillimeter mesh The heartland of radio astronomy. With its help, we can examine a large number of planetary systems around distant stars that are in the process of formation, or what can be called newborns, and protoplanetary disks composed of dust and gas. At the dawn of ALMA’s work, one of the first objects examined was the dust disk of a star called HL Tauri, located 480 light-years away in the constellation Taurus. Specialists saw gaps indicating the formation of planets, but the process still has many question marks. According to our ideas, the dust particles in the disk gradually stick together and form increasingly larger clumps, eventually turning into familiar celestial bodies at home.
We can obtain information about dust particles and dust clumps by polarizing the light coming from them. Polarization is a property that tells us about the level of vibration of light waves, and this is related to the shape of the particles, so measuring polarization tells us about dust particles. In the case of HL Tauri and surrounding areas New tests have been performedAnd polarization measurements are ten times greater than before. Thanks to this, the dust disk surrounding the star is also very detailed They can create an image Professionals, a record not only for this system.
The resolution of the new images is 5 astronomical units – this corresponds to the distance between the Sun and Jupiter – thanks to which many previously unseen details were revealed. For example, it turns out that the polarization of the dust disk half is stronger, and this is most likely a result of the fact that the distribution or shape of the dust particles in the disk is not the same everywhere.
Polarization makes successfully detected dust visible, shown in yellow in the illustration.
Source: NSF/AUI/NRAO/B. Saxton/Stevens et al
The grain can be spherical, flat like a pancake, or elongated like a grain of rice. These different shapes are responsible for allowing the vibration levels of light waves coming from them and propagating between them to pass through. Based on the measurements just made, the shape of the dust particles in the system is elongated, reminiscent of grains of rice, but even for their size, they calculated the limits within which they can move.
The polarization of the dust rings visible in the disk shows a more homogeneous image, indicating that the light coming from here may be scattered light. The polarization of the gaps between the rings is stronger than that of the rings, even though there is less matter in the gaps. Based on this, researchers believe that the molecules in the vacuoles line up in roughly the same direction, but the reason for this is unknown. All that is known is that the particles probably did not settle along the system’s magnetic lines of force, but rather relied on aerodynamic properties determined by their orbit around the young star, just as, for example, tree branches stretch to one side depending on the direction of the wind.
The researchers stressed the importance of extracting such detailed information from high-resolution ALMA measurements.
