In 2016, a group of scientists from New Jersey Institute of Technology discovered a strange signal coming from the Sun. Now, seven years later, they published in Nature Astronomy study in which they finally explain the origin of said signal: dawn.
From this point of view, this is surprising, since auroras are phenomena that occur both on Earth and on other planets of the solar system and are caused precisely by the Sun. Therefore, we can say that the aurora was caused by the royal star. to himself.
But in reality it is something more complex. We usually associate auroras with the lights that we see in the sky of our planetespecially at the north and south poles, where northern and southern lights, respectively. But the radiation emitted by these phenomena is not only in the visible light spectrum. There is also a high radio wave component. And that’s exactly what these scientists discovered on the Sun.
What auroras do we know?
Auroras are formed due to release of charged particlesemanating from storms and winds originating in the sunspots of our star. This means that the higher the solar activity, the more auroras there are.
In the case of Earth, these particles first encounter a magnetic field that prevents them from reaching the atmosphere. pushing them to extremes. These extremes are observed above the poles, where the magnetic field is much weaker. At this point, the particles accelerate, increasing the energy, which subsequently excites the atoms present in the atmosphere. It is this excitation that causes radiation, usually in the form visible lightthe shades of which depend on the composition of the atmosphere.
But there are also radio programs. They are not visible, but they are measured and characterized primarily by the fact that they are long-lasting bursts that remain active for a long time.
It should be noted that visible auroras are also found on other planets of the solar system. They were even found in Galilean moons of Jupiter. However, until now they have never been measured on the Sun itself.
Mysterious gusts of wind over the Sun
In 2016, the authors of a new study used Karl Jansky Very Large Array (VLA) to measure solar activity at much higher resolution than ever before.
This made it possible to discover something that had not been found before. A radio source in the solar atmosphere above a group of sunspots, transmitting signals at frequencies up to 1.7 GHz during 4.5 hours your complete observation.
Typically, bursts of this type, localized at this frequency, were very short, lasting a few minutes or, at most, an hour. This was something different.
So scientists set to work searching for a possible origin. And to find it, they just had to compare the bursts with the radio patterns coming from northern and southern lights.
It is no coincidence that it was found directly above the sunspots, or in other words, above the cooler areas of the Sun’s surface and with a much more intense magnetic field than the rest of the star. This was announced by the main author of the study, Shijo Yu.
“The cooler, more intensely magnetic regions of sunspots provide a favorable environment for the occurrence of ECM emission, drawing parallels with the magnetic polar caps of planets and other stars and potentially providing a local solar analog for studying these phenomena.”
Xiji Yu, astronomer and lead author of the study.
In the case of ECM this applies to electromagnetic radiation are generated by plasma electrons due to their rotation around magnetic field lines. In short, the Sun’s own magnetic field can also trap particles that cause auroras on other planets. In this case, it doesn’t give us a typical light show, but it does give us a picture of radio bursts that has never been measured before. Every day we see more and more clearly how little we know about our star.
Source: Hiper Textual
