According to the standard theory of star formation, stars are formed in cloudy nebulas and shortly after their birth they consume most of the gas that is present at their birthplace. The surrounding dust and gas can now be used to form planets.
This gas and dust then collapses and forms a rotating “Circumstellar disk”, which then draws the planet towards the star. Till now scientists were not aware of the reason behind this inward spiral motion of the planets towards their parent stars.
Scientists have now developed a new model that suggests that this disk hosts some magnetic instability that is the reason behind this inward spiral motion. This motion drags these newly formed planets into their final orbits.
Gas left over from the planet and the star formation process falls back on the surface of the star since they star emits ultraviolet radiation which attracts these particles of dust and gas. However, the main reason that could explain this transit of the gas from the disk to the stars was not available.
Now a new model has been developed by some researchers that can explain why some stars love to orbit quite close to their parent stars. They state that the gas in this disk orbits at different speeds depending on its distance from the star. This changes the magnetic field of the disk somewhat like a stretched rubber band which binds the inner and the outer rings together. The inner ring rotates faster than the outer one, so the magnetic field “rubber band” stretches in the direction of the rotation.
This phenomenon pulls back the inner rings and speeds the outer one. This slows the inner ring causing it to lose momentum and spiral inward to crash onto the star.
This inflow of gas drags objects such as planets closer to the star. The same process also explains as to why some gas giant planets orbit much closer to their star and as a result have a much higher surface temperature.
Via: usatoday
