Astronomers spot for the first time a coronal mass ejection from another star

On the sun, flares such as this one are often followed by an eruption of plasma and charged particles. Astronomers have now seen the first such coronal mass ejection from another star. SDO / GSFC / NASA

This is the first time that astronomers have seen a solar eruption in another star other than the sun, this coronal mass ejection was as massive as scientists expected, but less energetic. These events, are outbursts of plasma and charged particles projecting from the star, a well-known and recorded solar phenomenon, called CME. In the past astronomers detected flares on other stars, but never corresponding coronal mass ejection, this discovery has implications regarding the prospects for life in other worlds. 

The ejection is related to a flare detected 10 years ago from a giant star called HR 9024 about 450 light-years from Earth, which is about three times as massive as the sun and 10 times as wide. 

Coronal Mass Ejection. Arcs rise above an active region on the surface of the Sun in this image taken by the STEREO on February 15 of 2010. NASA Earth Observatory.

This was revealed on August 2 at the Cool Stars 20 meeting by astronomer Costanza Argiroffi of the University of Palermo in Italy, she and her colleagues discovered this using a new method for analyzing data which was taken by the Chandra X-ray Observatory. 

The team detected material moving up and down a loop of plasma extending from the star’s surface during the flare by measuring certain X-rays’ Doppler shift — the change in the wavelengths of the X-rays as material moved toward or away from the Earth. The researchers saw more material moving away from the star after the flare had stopped, and interpreted the observation as a coronal mass ejection. 

“People have looked for this for a long time, and this is the first time this has been seen,” says astrophysicist Julián Alvarado-Gómez of the Harvard-Smithsonian Center for Astrophysics in Cambridge, Massachusetts, who was not involved in the work. 

The ejection contained about 1 billion trillion grams of material, which is about what scientists expected based on estimates that extrapolated from the sun’s CMEs to bigger stars. But the outburst’s kinetic energy, measured by the escaping material’s speed, was much lower than expected. 

Alvarado-Gómez suggested that the star’s strong magnetic field may have held the eruption back. In computer simulations run by his group it showed that a strong magnetic field can sometimes act as a cage that keeps a CME tethered to the star, or slows the progress of ejections that make it out. 

That could help explain why scientists haven’t detected a CME from another star before. Strong stellar magnetic fields are associated with more flares, which should cause more ejections, so scientists have wondered at not being able to spot one. 

Fulguración solar. Wikipedia.

There is bad and good news from all this, for such a magnetic impediment could help life for orbiting exoplanets, if HR 9024 has any. In our solar system, the energy and matter released in both flares and CMEs can be devastating for other planets if not protected by a magnetic field, such is the case with Mars which has suffer the bombardments from our Sun since it hasn´t got a magnetic field. 

But not all is good, while star with strong magnetic fields helps planets to be safe from CMEs, this can be counterproductive, in the words of Alvarado-Gómez “The bad news is this energy has to go somewhere, and maybe it goes into powering more flares,” which aren’t weakened by the field, and since there are many potentially habitable worlds orbiting very close to particularly flare-prone stars, perhaps is not such good news after all. 

“If those flares are accompanied by these particle emissions at the same rate that they are in the sun,” says astronomer Cynthia Froning of the University of Texas at Austin, “it’s going to be very detrimental to the formation of life and the maintenance of those planets’ atmospheres.” 

A Solar Storm on August 1, 2010. Author: STEREO

Sources: Sciencenews, Wikipedia,