Washington: NASA in its latest study led by an Indian astronomer has claimed to have identified what makes the solar corona, the outermost peripheral part of the Sun’s atmosphere, extremely hot.
Any variations in the solar corona can affect the space weather and subsequently, the activities on Earth. Hence solar physicists have been engaged in deciphering the composition and behaviours of corona for many decades now. Among the commonest features displayed by the solar corona are loops, streams, plumes and ejections.
Similar to the green and mushy algal moss seen growing on a wet rock structure near water bodies, the Sun, too, has similar moss-like patchy structures made of plasma in the solar atmosphere. Under strong magnetic conditions, this moss grows and blossoms around the centre of a sunspot group. The moss-like structure is mainly due to chromospheric jets or ‘spicules’ interspersed with extreme ultraviolet emission elements.
The moss region is connected to the Sun’s lower atmosphere and the temperatures here can go as high as 5.5 lakh degrees Celsius, which is over 100 times hotter than the immediate layer below. This long-standing mystery of over 25 years has been partly addressed in the latest NASA study.
NASA scientists used solar observations obtained from two of its missions — the High-Resolution Coronal Imager (Hi-C) sounding rocket and Interface Region Imaging Spectrograph (IRIS) to decode the superheating mechanism.
