Our star is capable of producing flares strong enough to cause havoc on Earth. Strong solar activity affects electricity systems, telecommunications, and even life itself. However, the superflares that other stars release pale in comparison to the Sun’s erratic outbursts. What causes flare-ups? And what’s happening at far-off stars to increase the intensity of their flares?
The explanation seems straightforward: physics. or, more precisely, physics of stars and solar systems. A flare is essentially a star’s active area releasing magnetic energy. Such activity is observed on the Sun in relation to sunspot groups, which have strong magnetic field lines. As the lines “snap,” the magnetic energy that has been stored eventually releases. In the solar plasma, it accelerates charged particles and releases a burst of electromagnetic radiation into space.
Explaining Supeflares at Other Stars
On other stars, the same series of events takes place. There are spots on other stars, but the ones that are visible to us from Earth are typically far bigger than those on the Sun. A star’s “surface” may occasionally be covered up to one-third by starspots, which have magnetic fields associated to them. Therefore, it should come as no surprise that such stars will likewise produce flares.
Those explosions are typically referred to by scientists as stellar flares. “Super flares,” which are typically 100–10,000 times brighter than flares from the Sun, can be produced by stars that are active enough. Superflaring stars are more active because their magnetic fields are stronger than the Sun’s. It’s interesting to note that some of those flares are accompanied by an unexpected brilliant flare that lasts longer and is less strong.
Researchers were curious as to why superflares exhibit this intriguing “hiccup” in their flares. In order to develop a meaningful model of the event, a team led by associate professor Xudong Sun and postdoctoral researcher Kai Yang of the University of Hawaii Institute for Astronomy turned to the Sun. Then, using data from the Kepler and TESS telescopes, they examined star light curves to search for an odd “peak-bump” in light output.
“Even though we were never able to see these flares directly, we were able to identify the physics driving them by applying what we’ve learned about the Sun to other, cooler stars,” Yang stated. “These flares, which are far too small to be directly observed, were actually made easier to “see” by the way these stars changed in brightness over time.”
Modeling the Outbursts
The phenomena responsible for the “peak-bump” hiccups at other stars are invisible. Yang and colleagues then examined coronal loops, which are a regular formation on the Sun. When flares occurred on other stars (including the Sun), astronomers initially thought that the visible light originated from the lower layers of the stellar atmosphere. Superheated particles that are released from the corona and become electrified by magnetic outbursts, sometimes known as “reconnection,” heat them.
Large loops of magnetized plasma that extend from the solar surface into the corona are involved in the reconnection process. They split up, then get back together. That releases a great deal of energy in a brief period of time. The flare action is energized by the process of superheating the plasma. The Hawai’i team inquired as to whether the peak-bump glitch they observed at other stars may be produced by the same process. Yang modified a fluid simulation used to make solar loop models using solar data and observations from TESS and Kepler. Upon scaling it up, he discovered that a flare’s high energy injects a significant amount of mass into the loops. This produces a peak-bump-like concentrated emission of visible light at the onset of the flare.
Yang and colleagues’ model reproduces the Sun’s events and could very well account for the flares observed at other stars, especially in the TESS data. The timing and location of these flares should be the subject of additional research and observations. The group notes that additional studies in the extreme ultraviolet could advance our knowledge of the fundamental physics of superflares.
Superflares and Life
To put it mildly, life on planets around stars with superflares would be intriguing. M-, K-, and G-type dwarfs have the most active superflare stars. The strongest superflares would most likely cause some serious extinction events or eradicate all life on neighboring planets. Nonetheless, “not-so-powerful” flares from stars may be the source of the organic molecules required for life. Perhaps that is a part of the Earth’s history of life.
To put it mildly, life on planets around stars with superflares would be intriguing. M-, K-, and G-type dwarfs have the most active superflare stars. The strongest superflares would most likely cause some serious extinction events or eradicate all life on neighboring planets. Nonetheless, “not-so-powerful” flares from stars may be the source of the organic molecules required for life. Perhaps that is a part of the Earth’s history of life.
Thus, although we are not “blessed” with a star that constantly produces superflares, we are nevertheless in danger due to the Sun’s considerably smaller activity. By examining its eruptions along with those of other stars, scientists can have a better understanding of what to anticipate and perhaps even learn how to forecast these types of events more precisely in the future.
