One of the main things scientists look at is stellar activity. Red dwarf stars are prone to flare-ups because of their variable nature and being considered stable over time. If a star has multiple planets, the tendency to periodically flare could render them completely uninhabitable.
Our own stars may not be as stable as was thought. An international team of astronomer witnessed a massive mass ejection from EK Draconis, a G 1.5V yellow dwarf, which was located over 100 light-years away. These observations suggest that these ejections can get worse, which could be a dire warning for life here on Earth.
The study was led by Dr. Kosuke Namekata, a researcher at Kyoto University, the National Astronomical Observatory of Japan, and the National Solar Observatory. He was joined by researchers from multiple universities and the Nishi-Harima Astronomical Observatory.
Flares could be a threat to life on red dwarf planets. The credit is NASA/ESA/D. Player.
A solar storm is a stellar phenomenon known as a corona mass ejection. These ejections occur with our Sun frequently, and often accompany a stellar flare. Clouds of hot charged particles are sent into space. If a CME hits Earth, it could cause a lot of damage because Earth is protected from charged particles.
Satellites would be disabled, and Earth-based infrastructure like electrical grids would be knocked out, if astronauts were exposed to lethal radiation levels. The most well-known example of a powerful geomagnetic storm was the Carrington event in 1859. The events that have occurred in Earth's history are usually several thousand years apart.
The research team observed evidence that superflares may become worse for Sun-like stars over time. Yuta Notsu explained in a recent press release that she is a co-author.
There can be a serious impact on Earth and human society from coronal mass ejections. This kind of mass ejection could happen on our sun. This observation may help us understand how similar events have affected Earth and Mars over billions of years.
An artist's impression of a red dwarf star. Credit: NASA, the European Space Agency, and G. bacon.
The research was conducted by many of the researchers who collaborated with Yuta Notsu. Young Sun-like stars experience frequent superflares that are hundreds of times more powerful than solar flares. Superflares, which appear to happen once every thousand years, are known to occur on the Sun. The question was raised if a superflare could also lead to a massive mass ejection.
Astronomers have speculated about a possible relationship between these two phenomena, but no evidence has been found. Namekata, Notsu, and their colleagues decided to study EK Draconis, which is similar to our Sun in terms of size and mass, but is young compared to our Sun, which is 4.5 billion years old.
For the sake of their observations, Namekata, Notsu, and their colleagues used NASA's Transiting Exoplanet Survey Satellite (TESS) and Kyoto University's SEIMEI Telescope. On April 5th, 2020, the team observed EK Draconis erupt into a superflare, followed 30 minutes later by a massive ejection of super-hot plasma. Said Notsu.
This kind of mass ejection could happen on our Sun. This observation may help us understand how similar events have affected Earth and Mars over billions of years. It is what our Sun looked like 4.5 billion years ago.
The visualization depicts what a mass ejection might look like. The credit is NASA/Steele Hill.
Thefilament eruption phase is the first step in the ejection's life and the team was only able to observe it. The cloud was ten times larger than the most powerful CME ever recorded from a Sun-like star and had a top speed of over one million km. The event could show how dangerous space weather can be.
If an eruption from our Sun were to occur, it would have the potential to strip Earth of its atmosphere and make our planet sterile. Their findings show that the Sun could be capable of violent extremes, but they also show that superflares and super CMEs are rare for stars as old as the Sun. When our Solar System was still forming, Notsu explained, super CMEs may have been more common.
The evolution of planets like Earth and Mars could have been influenced by super-cGMPs, which could have played a role in how one gave rise to life while the other did not. He said that the atmosphere of Mars is very thin. We think that Mars had a thicker atmosphere in the past. Coronal mass ejections can help us understand what happened to the planet over billions of years.
If and when future generations begin to live on Mars, this knowledge could be useful. The planet will be warmer, wetter, and more liveable if the atmosphere is protected from solar activity.
Further reading: Nature.
